[Show abstract][Hide abstract] ABSTRACT: Leptin is a multifunctional hormone produced by the ob gene and is secreted by adipocytes that regulate food intake and energy metabolism. Numerous studies demonstrated that leptin is a novel neuroprotective effector, however, the mechanisms are largely unknown. Herein, we demonstrate the protective activities of leptin after ischemic stroke and provide the first evidence for the involvement of the connexin 43 (Cx43) in leptin-mediated neuroprotection. We found that leptin treatment reduces the infarct volume, improves animal behavioral parameters, and inhibits the elevation of Cx43 expression in vivo. In vitro, leptin reverses ischemia-induced SY5Y and U87 cells Cx43 elevation, secreted glutamate levels in medium and SY5Y cell death, these roles could be abolished by leptin receptor blocker. Additionally, leptin administration upregulated the extracellular signal-regulated kinase1/2 (ERK1/2) phosphorylation. Moreover, ERK1/2 inhibitors pretreatment reversed the effects of leptin on Cx43 expression, glutamate levels and cell apoptosis. In conclusion, the present study demonstrated that leptin can reduce the Cx43 expression and cell death both in vivo and in vitro via ERK1/2 signaling pathway. This result provides a novel regulatory signaling pathway of the neuroprotective effects of leptin and may contribute to ischemic brain injury prevention and therapy.
Full-text · Article · May 2014 · Cellular and Molecular Neurobiology
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the expression and clinical significance of leptin in lung cancer.
126 patients with lung cancer ranged from 30 to 83years of age were studied. Serum leptin levels were determined by ELISA. The mRNA and protein levels of leptin in normal and lung cancer tissues were measured by RT-PCR and immunohistochemistry. The relationships between leptin levels and clinicopathological factors were evaluated by Wilcoxon rank sum or Kruskal-Wallis H test.
Serum leptin levels in lung cancer patients were significantly higher compared to controls and leptin expression in lung cancer tissue was markedly increased than normal lung tissue (both P<0.050).
Determination of leptin levels might provide useful predictive information for lung cancer.
No preview · Article · Dec 2013 · Clinical biochemistry
[Show abstract][Hide abstract] ABSTRACT: Previous studies have demonstrated that both curcumin and leptin are protective factors against acute injuries. Here, we investigated whether leptin and its signaling pathway mediate the protective effects of curcumin.
A solid dispersion of curcumin-polyvinylpyrrolidone K30 was prepared and administered intraperitoneally. In vivo intestinal ischemia/reperfusion (I/R) injury in mice determined the effects of curcumin administration on inflammation, oxygen radical production, and leptin expression. In vitro studies using the venous epithelial cell line ECV-304 examined hypoxia/reoxygenation-induced leptin expression and release after curcumin administration. Furthermore, the effects on the leptin-regulated ERK1/2 and p38 MAPK signaling pathways were also explored.
Intestinal I/R induced marked bowel injuries. Curcumin treatment significantly improved animal survival and reduced the pathologic injuries in the intestines. Furthermore, the elevated intestinal water content and levels of malondialdehyde, interleukin 1β (IL-1β) and IL-6 were significantly decreased, but levels of superoxide dismutase increased. Interestingly, we found that the decreased leptin and its receptor Ob-Rb were restored by curcumin administration. In addition, in vitro studies showed that curcumin increased leptin expression and release after hypoxia/reoxygenation-induced cell injuries. Moreover, curcumin treatment restored decreased ERK1/2 phosphorylation (p-ERK1/2) and inhibited overactive p38 (p-p38) after injuries, and the effect was reversed by a leptin-specific antibody or Ob-R blocker.
These data suggest that leptin and Ob-Rb-dependent ERK and p38 MAPK signaling pathways may be involved in curcumin protection against intestinal I/R injury, and leptin may be a potential target of curcumin in intestinal I/R injury and other related acute diseases.
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of intensive rosuvastatin therapy on adhesion molecules in patients with peripheral atherosclerosis and explore the possible upstream mechanism.
Twenty asymptomatic patients with peripheral atherosclerosis were enrolled and given 5-20 mg/day rosuvastatin for 3 months. Before and after the treatment, the lipid profile and plasma vascular cell adhesion molecule-1 (VCAM-1) levels were examined. The expression of intercellular adhesion molecule-1 (ICAM-1) in the mononuclear cells was measured using flow cytometry, and the mRNA and protein expressions of peroxisome proliferator-activated receptor γ (PPARγ) were detected using RT-PCR and Western blotting, respectively.
Compared with the baseline levels, ICAM-1 expression decreased and PPARγ protein expression increased in the lymphocyts. Rosuvastatin therapy did not produce obvious effects on plasma VCAM-1 level or ICAM-1 expression in the monocyts in these patients.
Rosuvastatin produces anti-inflammatory effects by decreasing the expression of ICAM-1 in mononuclear cells, and its upstream mechanism may involve the PPARγ pathway.
No preview · Article · Nov 2012 · Nan fang yi ke da xue xue bao = Journal of Southern Medical University
[Show abstract][Hide abstract] ABSTRACT: To explore the effect of leptin on expression of Cx43 after rat cerebral ischemia/ reperfusion injury and its related mechanism.
Forty-five male kunming mice were randomly divided into 3 groups: sham group, model group and leptin group. Mouse models of transient focal cerebral ischemia were established by occlusion of the right middle cerebral artery for 2 h followed by 24 h reperfusion in model and leptin group. Mice of leptin group were intraperitoneally injected with 1 mg/kg leptin at 0 minute after ischemia. The infarct volume and neurological deficit scores following leptin treatment were determined using TTC staining and the Longa's score, respectively, to evaluate the protective effect of leptin against ischemic cerebral injury. The histopathological changes in the brain were observed with HE staining. The astrocytes of SD rat cerebral cotex were cultured primaryly and purified, and then divided them into four groups: control, model, leptin 100 microg/L, and leptin 500 microg/L. The cerebral astrocytes with hypoxia/reoxygenation injury were induced. The cellular viability of injury was detected by MTT assay. The effect of leptin on Cx43 expression was detected by Western blot in brain tissues and astrocytes.
Compared with the model group, the neurological deficits and cerebral infarct volume of leptin group were reduced (P< 0.05), the histopathological injury in the brain tissues was alleviated and the expression of Cx43 was decreased markedly (P < 0.01). The survival rate of astrocytes was increased significantly in leptin 500 microg/L group (P < 0.01), whereas the Cx43 expression of astrocytes decreased (P < 0.01). But the difference of leptin 100 mcirog/L was not significant (P > 0.05).
Leptin can ameliorate cerebral pathological changes in the event of IR injury by suppressing the expression of Cx43 both in vivo and vitro experiments.
No preview · Article · May 2012 · Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition
[Show abstract][Hide abstract] ABSTRACT: Recent research has indicates that leptin plays a protective role in traumatic brain injury. We studied the protective effect of leptin on cerebral ischemia/reperfusion injury by using mice transient focal cerebral ischemia/reperfusion injury model.
The distribution of 125I-leptin in the mouse brain was assessed by radioimmunoassay method. Mouse models of transient focal cerebral ischemia were established by occlusion of the right middle cerebral artery for two hours followed by 24 hours reperfusion. The neurologic deficits and infarct volume were determined using the Longa's score and 2,3,5-triphenyltetrazolium chloride staining, respectively. Regional cerebral blood flow was monitored by a laser-Doppler blood flowmeter. The levels of malondialdehyde, nitric oxide, nitric oxide synthase, and superoxide dismutase were detected according to respective assay kit. The histologic changes and neuronal apoptosis were observed with hematoxylin and eosin and transferase-mediated dUTP-biotin nick end labeling staining, respectively. The expression of B-cell lymphoma/leukemia-2 (Bcl-2) and cysteineasparateprotease-3 (caspase-3) were investigated by Western blot and real-time polymerase chain reaction assay.
Leptin decreased infarct volume and neurologic defects and improved regional cerebral blood flow and microvascular branch blood flow after injury. The malondialdehyde and nitric oxide levels were reduced, and superoxide dismutase level was increased after leptin treatment, which also minimized histologic changes and neuronal apoptosis, led to the upregulation of Bcl-2 and downregulation of caspase-3 expression after injury.
Peripherally administered leptin crossed the blood-brain barrier and was distributed into multiple regions of the brain; in the brain, leptin directly alleviated the injury-evoked damages by reducing oxidative stress and neuronal apoptosis.
[Show abstract][Hide abstract] ABSTRACT: Ischemic stroke is a medical emergency triggered by a rapid reduction in blood supply to localized portions of the brain, usually because of thrombosis or embolism, which leads to neuronal dysfunction and death in the affected brain areas. Leptin is generally considered to be a strong and quick stress mediator after injuries. However, whether and how peripherally administered leptin performs neuroprotective potency in cerebral stroke has not been fully investigated. It has been reported that CGRP(8-37), an antagonist of the CGRP receptor, could reverse the protective effect of leptin on rats with CIP (caerulein-induced pancreatitis). However, the question remains: are leptin and CGRP associated in cerebral ischemia/reperfusion injury? The present study attempted to evaluate the relationship between CGRP expression and leptin neuroprotective effects (1mg/kg in 200 μL normal saline, i.p.) on focal cerebral ischemia/reperfusion injury in mice and the protective effect of leptin (500 μg/L) on neurons during hypoxia/reoxygenation injury. Peripheral administration of leptin alleviated injury-evoked brain damage by promoting CGRP expression, improving regional cerebral blood flow, and reducing local infarct volume and neurological deficits. Furthermore, leptin also promoted bcl-2 expression and suppressed caspase-3 in vivo and vitro after injury. Administration of CGRP(8-37) (4 × 10(-8)mol/L) partly abolished the beneficial effects of leptin, and restored the normal expression levels of bcl-2 and caspase-3 in neurons, which indicated that leptin-induced protection of neurons was correlated with release of CGRP. These results indicate that the neuroprotective effect of leptin against cerebral ischemia/reperfusion injury may be strongly relevant to the increase of CGRP expression.
No preview · Article · Sep 2011 · European journal of pharmacology
[Show abstract][Hide abstract] ABSTRACT: Recently, research has indicated that leptin plays a protective role in traumatic brain and liver injury. We studied the protective effect of leptin on intestinal I/R injury and examined its mechanism by using mice intestinal I/R model and murine peritoneal macrophage hypoxia/reoxygenation (H/R) injury model.
Leptin was intraperitoneally administrated at 45 minutes after ischemia, then reperfusion for two hours. Cells were treated with different concentrations of leptin at three hours after hypoxia, then reoxygenation for six hours. Mice intestines were harvested for histopathologic properties. The malondialdehyde, nitric oxide (NO), interleukin-6, and total antioxidative capacity were detected according to respective assay kit. Phosphorylated extracellular regulated kinase1/2 (p-ERK1/2) and phosphorylated cytosolic phospholipase A(2) (p-cPLA2) were determined by Western blot assay.
Here, we show that leptin reduced intestinal histologic alterations, malondialdehyde and interleukin-6 levels but increased the endogenous leptin expression and NO production in the intestines. Leptin also increased the NO and total antioxidative capacity levels in cells. We further demonstrated that leptin markedly activated ERK1/2 in the intestines and activated ERK1/2 and cPLA2 in the cells. Moreover, the protective effect of leptin against intestinal I/R injury and elevated NO production was attenuated by blocking the ERK1/2 pathway.
These data demonstrate that leptin ameliorated intestinal I/R and peritoneal macrophage H/R injury by enhancing ERK1/2 phosphorylation and promoting the NO production signaling pathway.
[Show abstract][Hide abstract] ABSTRACT: To study the effect of Leptin on neuron apoptosis in mice with cerebral ischemia injury and its mechanism.
Seventy-five mice were randomly divided into three groups. Focal cerebral ischemia/reperfusion injury model in mice was reproduced by middle cerebral artery occlusion for 2 hours followed by reperfusion. In Leptin intervention group mice were given Leptin 1 μg/g during cerebral ischemia by intraperitoneal injection. Mice in the model group were given equal amount of phosphate buffer saline. After reperfusion for 24 hours, the neuron apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. The mRNA and protein expression of apoptosis relative gene caspase-3 and bcl-2 were determined by reverse transcription-polymerase chain reaction (RT-PCR) and immuno histochemistry.
Most of neuron necrosis was observed in cerebral ischemia center in model group. Compared with sham-operation group, neuron apoptosis rate, mRNA and protein expression of caspase-3 and bcl-2 in model group increased significantly [apoptosis rate: (68.65 ± 0.79)% vs. (4.40 ± 0.00)%, caspase-3 mRNA: 2.563 ± 0.250 vs. 0.153 ± 0.020, bcl-2 mRNA: 0.337 ± 0.100 vs. 0.125 ± 0.030, caspase-3 protein (absorbance value, A value): 0.57 ± 0.05 vs. 0.37 ± 0.03, bcl-2 protein (A value): 0.51 ± 0.04 vs. 0.35 ± 0.01, all P<0.01]. The apoptosis rate of penumbra neurons was reduced in Leptin intervention group significantly compared with model group [(42.30 ± 8.45)% vs. (68.65 ± 0.79)%, P<0.01]. Compared with model group, the mRNA and protein expression of caspase-3 in Leptin intervention group were reduced significantly [caspase-3 mRNA: 2.267 ± 0.040 vs. 2.563 ± 0.250, caspase-3 protein (A value): 0.45 ± 0.04 vs. 0.57 ± 0.05, P>0.05 and P<0.01], and the mRNA and protein expression of bcl-2 in Leptin intervention group upregulated significantly [bcl-2 mRNA: 0.662 ± 0.040 vs. 0.337 ± 0.100, bcl-2 protein (A value): 0.76 ± 0.09 vs. 0.51 ± 0.04, both P<0.01].
Leptin could reduce apoptosis of neurons through down-regulation of the expression of caspase-3 and up-regulation of the expression of bcl-2. The results suggest that Leptin plays a neuroprotective role in cerebral ischemia injury.
No preview · Article · Jun 2011 · Zhongguo wei zhong bing ji jiu yi xue = Chinese critical care medicine = Zhongguo weizhongbing jijiuyixue
[Show abstract][Hide abstract] ABSTRACT: To observe the effects of Xuebijing Injection in patients with severe pneumonia, and to explore the mechanism.
Eighty cases of severe pneumonia are randomly assigned to the Xuebijing treatment (forty cases) and the control group (forty cases), with the same routine therapy provided in both groups. Clinical effective rates, inflammatory factors and organ function were observed in both groups.
The effective rate was higher in Xuebijing group than that of the control group (80.0% vs. 67.5%, P < 0.05). As compared with the control group, the LDH, alpha1-AG, alpha1-AT levels and the peak body temperature decreased markedly with the Xuebijing treatment going, and the secretion of TNF-alpha, IL-6, IL-8 was suppressed in Xuebijing group; but no significant difference was found in leptin level.
Xuebijing Injection may show a protective effect in patients with severe pneumonia. The mechanism is possibly with the decreased secretion of TNF-alpha, IL-6, and IL-8.
No preview · Article · Mar 2011 · Journal of Traditional Chinese Medicine
[Show abstract][Hide abstract] ABSTRACT: To determine Leptin levels in supernatant fluid of culture of human umbilical vein endothelial cells (ECV-304) after being challenged by lipopolysaccharide (LPS) and calcium ion vector A23187, and to explore the possible relation between Leptin release and cytosolic phospholipase A(2) (cPLA(2)) activity in an inflammatory cell model.
ECV-304 cells were cultured in vitro. Experiment 1: the cells were divided into seven groups: blank control group, LPS 5, 10, 20 μg/ml stimulation groups, A23187 0.1, 1.0, 10.0 μmol/L stimulation groups. The supernatants were collected at 6, 12 and 24 hours.Experiment 2: according to the results of experiment 1, the cells were divided into eight groups: blank control group, LPS 20 μg/ml stimulation group, the inhibitor of cPLA2 AACOCF3 0.1, 1.0, 10.0 μmol/L plus LPS stimulation groups, the inhibitor of mitogen-activated protein/extracellular signal-regulated protein kinase kinase 1/2 (MEK1/2) U0126 0.1, 1.0, 5.0 μmol/L plus LPS stimulation groups, with AACOCF3 or U0126 added 1 hour before the addition of LPS, and the supernatants were collected 24 hours after the addition of LPS. Leptin level was determined by radioimmunoassay.
Experiment 1: with increase in LPS concentration and prolongation of time, Leptin release was decreased gradually. After 24 hours of interaction the concentration of Leptin (ng/ml) in LPS 20 μg/ml group was decreased significantly compared with the blank control group (0.540±0.109 vs. 0.823±0.048,P<0.05). However, A23187 had no significant effect on Leptin release. Experiment 2: LPS rendered cells to release less Leptin (ng/ml: 0.558±0.069 vs. 0.825±0.067,P<0.05); by adding AACOCF3 or U0126 in different concentration before adding LPS rendered the cells to release more Leptin (ng/ml), and it showed concentration-dependent (the AACOCF3 0.1, 1.0, 10.0 μmol/L groups were 0.673±0.135, 0.723±0.055, 0.797±0.062, respectively; the U0126 0.1, 1.0, 5.0 μmol/L groups were 0.698±0.112, 0.862±0.184, 0.935±0.145, respectively). The release of Leptin in AACOCF3 1.0 μmol/L, 10.0 μmol/L and U0126 1.0 μmol/L, 5.0 μmol/L groups was significantly higher than LPS 20 μg/ml stimulation group (all P<0.05).
There is a possible relation between Leptin release and cPLA 2 activity in inflammatory cells induced by LPS.
No preview · Article · Feb 2011 · Zhongguo wei zhong bing ji jiu yi xue = Chinese critical care medicine = Zhongguo weizhongbing jijiuyixue
[Show abstract][Hide abstract] ABSTRACT: To explore the effect of rat myocardial ischemia/reperfusion (I/R) injury on serum Leptin, endothelin (ET), C-reactive protein (CRP) and myocardial Leptin expression, and discuss the role of Leptin in myocardial I/R injury.
Fifty Sprague-Dawley (SD) rats were randomly divided into sham-operation, ischemia and I/R 1, 2, 3 hours groups, with 10 rats in each group. Anterior descending artery of the left coronary artery was ligated for 45 minutes and released for 1, 2 and 3 hours to establish myocardial I/R model, and the said artery of the rats in sham-operation group was not ligated. Blood from left femoral artery was collected at different time points, and serum Leptin, ET and CRP contents were detected. Myocardial tissue was harvested, and stained with hematoxylin-eosin (HE) and immunohistochemistry for its observation of the myocardial pathological changes and Leptin protein expression.
Serum Leptin content (μg/L) of ischemia group was significantly lower than that of sham-operation group (4.69±1.67 vs. 6.48±2.02, P<0.05); as the reperfusion time was prolonged, serum Leptin level increased gradually, and the level of I/R 3-hour group recovered to that before injury [(6.59±2.58) μg/L]. ET content (ng/L) of ischemia group was significantly higher than that of sham-operation group (110.58±37.86 vs. 80.74±34.43, P<0.05), the levels of ET in I/R 1, 2 and 3 hours groups were significantly lower than those of ischemia group (35.87±13.56, 31.98±10.88, 34.56±14.37 vs. 110.58±37.86, all P<0.05). CRP content (mg/L) of ischemia group was significantly higher than that of sham-operation group (13.12±4.82 vs. 3.24±1.72, P<0.01); as the reperfusion time was prolonged, serum CRP level increased gradually, and the levels of I/R 1, 2 and 3 hours groups were significantly higher than those of ischemia group (18.37±6.48, 24.30±9.51, 27.08±8.32 vs. 13.12±4.82, all P<0.05). Pathological examination showed that there was necrosis of ischemic myocardial cells in ischemia group, with mild congestion and edema in interstitial spaces. After I/R injury, the myocardial cells showed coagulative necrosis, and there was severe congestion of myocardial interstitial. Immunohistochemistry results showed that there was a tendency of decrease in Leptin protein expression in the early phase but increase in the late phase after the injury.
Leptin content in the serum and myocardial tissue decreases significantly in the early phase after myocardial I/R but increases gradually in the rehabilitative phase, suggesting that Leptin maybe a stress protective factor against I/R-induced myocardial injury. There is a possible association between Leptin and the early increase followed by a delayed decrease of ET as well as the increase of CRP.
No preview · Article · Nov 2010 · Zhongguo wei zhong bing ji jiu yi xue = Chinese critical care medicine = Zhongguo weizhongbing jijiuyixue
[Show abstract][Hide abstract] ABSTRACT: To evaluate the role of leptin in the internal disorders during hepatic ischemia/reperfusion injury.
A rat model of 70% hepatic ischemia/reperfusion injury was established, with groups of sham-operation (Sham), 60 min ischemia/60 min reperfusion (I60'R60'), I60'R150', I60'R240' and I60'R360'. Serum leptin was detected by a self-produced radioimmunoassay; serum glucose, total anti-oxidation capacity, myeloperoxidase, alanine transaminase and diamine oxidase were determined by relevant kits, while histological alterations and protein levels of leptin in the lung, liver and duodenum were examined by hematoxylin-eosin staining and immunohistochemistry. Spearman's rank correlation between leptin and other variables or grading of tissue impairment were analyzed simultaneously.
Serum leptin in I60'R360' was significantly higher than in Sham and I60'R240' groups (both P < 0.05), serum glucose in I60'R360' was higher than in Sham and I60'R150' (both P < 0.05), and serum total anti-oxidation capacity in I60'R240' and I60'R360' were higher than in Sham (both P < 0.05) and I60'R150'groups (both P < 0.01). Serum myeloperoxidase in groups of I60'R240' and I60'R360' were lower than in I60'R150'group (both P < 0.05), serum alanine transaminase in the four reperfusion groups were higher than in the Sham group (all P < 0.05), while serum DAO in I60'R360' was lower than in I60'R60' (P < 0.05). Histological impairment in the lung, liver and duodenum at the early phase of this injury was more serious, but the impairment at the later phase was lessened gradually. Protein levels of leptin in the lung in the four reperfusion groups were significantly lower than in the Sham group (all P < 0.01), decreasing in the order of I60'R150', I60'R60', I60'R360' and I60'R240'; the levels in the liver in I60'R60' and I60'R240' were higher than in the Sham group (both P < 0.01), while the levels in I60'R240' and I60'R360' were lower than in I60'R60' (both P < 0.01); the levels in duodenum in I60'R240' and I60'R360' were higher than in Sham, I60'R60' and I60'R150' (all P < 0.01), while the level in I60'R150' was lower than in I60'R60' (P < 0.05). There was a significantly positive correlation between serum leptin and alanine transaminase (ρ = 0.344, P = 0.021), a significantly negative correlation between the protein level of leptin in the lung and its damage scores (ρ = -0.313, P = 0.036), and a significantly positive correlation between the protein level of leptin in the liver and its damage scores (ρ = 0.297, P = 0.047).
Endogenous leptin fluctuates in hepatic ischemia/reperfusion injury, exerts a potency to rehabilitate the internal disorders and represents a potential target for supportive therapy.
Preview · Article · Nov 2010 · World Journal of Gastroenterology
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of leptin on apoptosis of rat cerebral astrocytes with ischemia/ hypoxia injury and its mechanism.
The cerebral astrocytes with ischemic/hypoxia injury were induced in neonatal SD rats. The cellular viability of injury of astrocytes was detected by MTT assay. The apoptosis of astrocyte were detected with Annexin V-FITC kit. The effect of leptin on the expression of apoptosis factor bcl-2, bax, caspase-3 was detected by RT-PCR and Western blot.
Compared with the ischemia group, the cellular viability of leptin intervention group increased significantly (P < 0.01), while the astrocytes apoptosis of leptin intervention group decreased significantly (P < 0.01). The mRNA and protein expression level of antiapoptosis factor bcl-2 in leptin intervention group was much higher than that of ischemia group (P < 0.01), whereas the mRNA and protein expression of bax and caspase-3 was much lower than that of ischemia group (P < 0.01).
Leptin could significantly decrease the apoptosis of astrocytes with ischemia/hypoxia injury, and it i relevant to the increase of bcl-2 expression and the decrease of bax caspase-3 expression level.
No preview · Article · May 2010 · Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE; To study the changes of leptin after hepatic ischemia/reperfusion (H-I/R) and its effects on H-I/R-induced hepatic injury.
A 70% H-I/R model of rats was established. The rats were divided into groups with different reperfusion times and sham-operation group. Radioimmunoassay was applied to measure protein levels of leptin in serum and adipose tissues of the rats. Enzyme-colorimetry was used to detect serum alanine transaminase. Hematoxylin-eosin staining and immunohistochemistry were applied to investigate pathological variations and protein expressions of leptin in livers, respectively. RT-PCR was used to detect leptin mRNA expressions in adipose tissues and livers.
Compared with the sham-operation group, serum leptin increased significantly in the 60 min ischemia/360 min reperfusion (I60' R360') group; protein level of leptin in adipose tissues increased significantly in the I60'R60' group; serum alanine transaminase increased significantly in all of the four reperfusion groups; protein expressions of leptin in livers increased significantly in the I60'R60' and 160'R240' groups; leptin mRNA expression in adipose tissues decreased significantly in the I60'R150' group; leptin mRNA expression in livers increased significantly in the 160'R60' group; leptin mRNA expressions in livers decreased significantly in the I60'R150', I60'R240' and I60'R360' groups. Pathological investigation showed that hepatic impairments at the early phase of H-I/R were more serious. The impairments at the later phase lessened gradually.
The change of leptin expressions after H-I/R may be a protective factor to withstand H-I/ R-induced hepatic injury.
No preview · Article · Nov 2009 · Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition
[Show abstract][Hide abstract] ABSTRACT: Heart-type fatty acid-binding protein (H-FABP) is widely distributed and has been used to diagnose certain diseases. However, its alteration during infection-evoked organ dysfunction, and the potential association between leptin and it in injury or infection has not been investigated. In the current study, serum H-FABP, leptin, C-reactive protein and interleukin-1beta in the patients with pulmonary infection-induced multiple organ dysfunction were detected. Moreover, a mouse model of sepsis was established, and serum alanine transaminase, uric acid, tissue H-FABP, myeloperoxidase, superoxide dismutase activity and histological alterations in lung and intestine were investigated. Serum H-FABP and leptin increased simultaneously and significantly in the patients, and leptin alleviated pulmonary and intestinal injuries by restraining tissue H-FABP secretions in the mouse model of sepsis. Other investigated variables showed different but independent alterations. In conclusion, H-FABP represents a useful diagnostic marker for organ dysfunction, and its association with leptin will be a novel target for emergency aid.
No preview · Article · Sep 2009 · European journal of pharmacology
[Show abstract][Hide abstract] ABSTRACT: To explore the effect of ethyl pyruvate (EP) and alkaline phosphatase (ALP) on injuries of sepsis and the mechanism involved.
A murine sepsis model of cecal ligation and puncture was reproduced, and 90 male Kunming mice were divided randomly into sham-operation, model and EP-intervention groups. 75 mg/kg EP was intraperitoneally injected in EP groups 1 hour after establishment of model, and the mice in model group were given a same volume of Ringer's solution. The eyeballs were removed in the latter two groups, and mice were sacrificed at 15 minutes and 1, 3 and 6 hours in subgroups of 10 mice each. ALP, uric acid (UA) and ratio of lactic acid and pyruvic acid were determined in serum and homogenized lung tissue by autonomous biochemical analyzer, and pathological changes in intestine were observed by hematoxylin-eosin (HE) staining.
Compared with sham-operation group, serum ALP in model groups and EP groups decreased significantly (P<0.05 or P<0.01), and ALP level of EP group was significantly lower than model group at 6 hours after injury (P<0.05). Compared with sham-operation group, serum UA in model group increased significantly at 1 hour, and reached the highest level at 3 hours (both P<0.05) but decreased significantly later. UA in EP group was significantly lower than that in model group at 1 hour and 3 hours (both P<0.05). Lactic acid/pyruvic acid ratio in lung homogenate of EP group was significantly lower than that of the model group at all the time points (all P<0.05). Intestinal structural damages were distinctly improved in EP group compared with model group at 3 hours and 6 hours (both P<0.05 ).
EP promotes the utilization of serum ALP, decreases serum UA, ameliorates acidosis and intestinal damages, thus exerting a protective effect on sepsis-induced organ injuries.
No preview · Article · Aug 2009 · Zhongguo wei zhong bing ji jiu yi xue = Chinese critical care medicine = Zhongguo weizhongbing jijiuyixue
[Show abstract][Hide abstract] ABSTRACT: To investigate the protective effect of leptin against cerebral ischemia/reperfusion injury in mice.
Mouse models of transient focal cerebral ischemia were established by occlusion of the right middle cerebral artery for 2 h followed by 24 h reperfusion. The infarct volume and neurological deficit scores following leptin treatment were determined using TTC staining and the Longa's score, respectively, to evaluate the protective effect of leptin against ischemic cerebral injury. The levels of lactate dehydrogenase (LDH), malondialdehyde (MDA) and nitric oxide (NO) in the brain tissue were measured by colorimetry. The histopathological changes in the brain were observed with HE staining, and the expression of glial fibrillary acidicprotein (GFAP) was detected by immunohistochemistry.
Leptin treatment markedly reduced cerebral infarct volume and neurological deficits induced by transient ischemia. The LDH, MDA and NO levels in the brain tissues were significantly decreased after leptin treatment, which also alleviated the histopathological injury, maintained the normal morphology of the astrocytes and increased the expression of GFAP.
Leptin produces obvious protective effect against cerebral ischemia/reperfusion injury by inhibiting lipid peroxidation, stabilizing the internal environment and adjusting the activity of the astrocytes.
No preview · Article · May 2009 · Nan fang yi ke da xue xue bao = Journal of Southern Medical University
[Show abstract][Hide abstract] ABSTRACT: To explore the effect of rat myocardial ischemia/reperfusion injury on leptin levels in serum and myocardium, and discuss the role of leptin in myocardial ischemia/reperfusion injury.
A myocardial ischemia/reperfusion injury model of rats was established, serum lactate dehydrogenase (LDH) and leptin levels were detected, and histopathological changes and leptin expressions in myocardium were investigated by hematoxylin-eosin staining and immunohistochemistry, respectively.
Serum LDH of ischemia and reperfusion groups increased significantly (P < 0.05), suggesting the model was successfully established and a certain degree of local myocardial injury was induced. Serum leptin of ischemia group (6.34 +/- 2.49) ng/ml was significantly lower than control group (7.50 +/- 2.93 ng/ml, P <0.05). Leptin levels recovered gradually after reperfusion, reached (8.32 +/- 1.74)ng/ml at 2 h after reperfusion, which recovered to the level before injury (8.38 +/- 2.56) ng/ml, and showed a trend to increase as reperfusion time was elongated. Immunohistochemistry results showed that as compared with sham-operation group, myocardial leptin protein expressions of the other four groups were all significantly lower (P < 0.01), and decreased in order by 45 min ischemia/1 h reperfusion, 45 min ischemia/3 h reperfusion, 45 min ischemia and 45 min ischemia/2 h reperfusion.
Leptin level in the blood decreases significantly at the early 45 min after myocardial ischemia/reperfusion injury, and its expression in myocardium also decreases significantly. There may be a certain relationship between the pathological injury of myocardium and the changes of leptin.
No preview · Article · May 2009 · Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology
[Show abstract][Hide abstract] ABSTRACT: To explore the distribution of leptin expression and the effect of sepsis on leptin protein and mRNA levels.
Vital organ samples including hypothalamus, lung, liver, spleen, stomach, duodenum, kidney, epididymal fat pad and testis of normal rats were collected. The mRNA expressions of leptin in those samples were determined by RT-PCR. The sepsis rat model induce by cecal ligation and perforation (CLP) was established, setting groups of sham-operation, CLP model, CLP + intralipid injection, CLP + estradiol injection and CLP + insulin injection, as the latter three groups were set to intervene energy metabolism and neuroendocrine function. Radioimmunoassay was applied to measure serum leptin concentrations in each group at 12 h after injury, while RT-PCR was also used to detect Leptin mRNA expressions in hypothalamus, fat and lung after injury.
Leptin mRNA expressions were confirmed in all the above nine vital organs, with the highest in kidney but the lowest in testis. The serum leptin level showed no significant difference between sham operation group and other four groups. Compared with sham operation group, the Leptin mRNA level in CLP group decreased significantly in hypothalamus, fat and lung, while that in the other three groups showed different changes. The effect of intralipid on Leptin mRNA expression was found to be a dual-direction pattern, with central stimulation but peripheral inhibition.
Leptin is widely expressed in multiple vital organs, and it may be a protective factor to promote recovery of sepsis-induced internal disorders.
No preview · Article · Jun 2008 · Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition