Publications (13)19.26 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: Voltage-gated potassium channels (KV) regulate pain transmission by controlling neuronal excitability. Changes in KV expression patterns may thus contribute toward hyperalgesia following nerve injury. The aim of this study was to characterize KV current density in dorsal root ganglion (DRG) neurons following chronic constriction injury (CCI) of the right sciatic nerve, a robust model of post-traumatic neuropathic pain. The study examined changes in small-diameter potassium ion currents (<30 µm) in neurons in the L4-L6 DRG following CCI by whole-cell patch-clamping and the association with post-CCI mechanical and thermal nociceptive thresholds. Compared with the control group, 7 days after CCI, the mechanical force and temperature required to elicit ipsilateral foot withdrawal decreased significantly, indicating tactile allodynia and thermal hyperalgesia. Post-CCI neurons had a significantly lower rheobase current and depolarized resting membrane potential than controls, suggesting KV current downregulation. Some ipsilateral DRG neurons also had spontaneous action potentials and repetitive firing. There was a 55% reduction in the total KV current density caused by a 55% decrease in the sustained delayed rectifier potassium ion current (IK) density and a 17% decrease in the transient A-type potassium ion current (IA) density. These results indicated that changes in DRG neuron IK and IA current density and concomitant afferent hyperexcitability may contribute toward neuropathic pain following injury. The rat CCI model may prove valuable for examining pathogenic mechanisms and potential therapies, such as KV channel modulators.
- [Show abstract] [Hide abstract] ABSTRACT: Although fulminant hepatitis represents a ubiquitous human health problem, there is a lack of effective therapeutic strategies that have few side‑effects and the precise mechanisms underlying fulminant hepatitis are not fully understood. Phosphoinositide 3‑kinase (PI3K) is a pivotal kinase known to regulate inflammatory responses in hepatic diseases. Although previous research indicates that PI3K is involved in cardiac diseases, including myocardial infarction, it currently remains unclear whether the inhibition of PI3K is essential for ameliorating the severity of lipopolysaccharide (LPS)‑induced hepatitis. The aim of the present study was to investigate whether pharmacological blockade of PI3K ameliorates the development of LPS‑induced murine acute hepatic injury. A murine model of LPS‑induced acute hepatic injury was used to investigate the therapeutic effect of the pan‑PI3K inhibitor, LY294002 on murine fulminant hepatitis and to investigate potential underlying mechanisms. The current report presents the in vivo role of LY294002 in protecting the mice from fulminant hepatitis. LY294002 was observed to exert significant protective effects on the liver by reducing the activities of alanine aminotransferase and aspartate aminotransferase, as well as by improving the histological architecture of the liver. In LPS‑induced hepatitis, treatment with LY294002 clearly inhibited intrahepatic synthesis of various disease‑relevant proinflammatory cytokines, including tumor necrosis factor‑α, interleukin (IL)‑6, IL‑1β and interferon‑γ. Furthermore, LY294002 was observed to significantly inhibit IκB phosphorylation in LPS‑injured mouse liver samples. Therefore, LY294002 may protect the liver from LPS‑induced injury by inhibition of the IκB‑nuclear factor κ‑light‑chain‑enhancer of activated B cell dependent signaling pathway. Thus, the current report provides evidence that LY294002 exerts potent effects against LPS‑induced hepatic injury, indicating its potential therapeutic value for the treatment of acute hepatitis.
- [Show abstract] [Hide abstract] ABSTRACT: Ischemia postconditioning (IpostC) is an effective way to alleviate ischemia and reperfusion injury; however, the protective effects seem to be impaired in candidates with diabetes mellitus. To gain deep insight into this phenomenon, we explored the role of DJ-1, a novel oncogene, that may exhibit powerful antioxidant capacity in postconditioning cardioprotection in a rat model of myocardial ischemia reperfusion injury. Compared with normal group, cardiac DJ-1 was downregulated in diabetes. Larger postischemic infarct size as well as exaggeration of oxidative stress was observed, while IpostC reversed the above changes in normal but not in diabetic rats. DJ-1 was increased after ischemia and postconditioning contributed to a further elevation; however, no alteration of DJ-1 was documented in all subgroups of diabetic rats. Alteration of the cardioprotective PI3K/Akt signaling proteins may be responsible for the ineffectiveness of postconditioning in diabetes. There is a positive correlation relationship between p-Akt and DJ-1 but a negative correlation between infarct size and DJ-1, which may partially explain the interaction of DJ-1 and IpostC cardioprotection. Our result indicates a beneficial role of DJ-1 in myocardial ischemia reperfusion. Downregulation of cardiac DJ-1 may be responsible for the compromised diabetic heart responsiveness to IpostC cardioprotection.
- [Show abstract] [Hide abstract] ABSTRACT: To investigate the neurotoxicity of intrathecal injections of dexmedetomidine, Sprague-Dawley rats were intrathecally injected with dexmedetomidine at doses of 0.75, 1.50 and 3.00 μg/kg into the spinal dorsal horn. We found that c-Fos expression in the rat spinal dorsal horn peaked at 7 hours following the 3.00 μg/kg dexmedetomidine injection, while the levels of c-Fos expression following 0.75 and 1.50 μg/kg dexmedetomidine were similar to those in the spinal dorsal horn of normal rats. At 48 hours following administration, the level of c-Fos expression was similar to normal levels. In addition, the intrathecal injections of dexmedetomidine increased paw withdrawal mechanical thresholds and prolonged thermal tail flick latencies. These results indicate that dexmedetomidine has pronounced antinociceptive effects. However, dexmedetomidine appears to have neurotoxic effects in the spinal cord because it increased c-Fos expression in the spinal dorsal horn within 7 hours following administration.
- [Show abstract] [Hide abstract] ABSTRACT: The present study established global brain ischemia using the four-vessel occlusion method. Following three rounds of reperfusion for 30 seconds, and occlusion for 10 seconds, followed by reperfusion for 48 hours, infarct area, the number of TUNEL-positive cells and Bcl-2 expression were significantly reduced. However, glycogen synthase kinase-3β activity, cortical Bax and caspase-3 expression significantly increased, similar to results following ischemic postconditioning. Our results indicated that ischemic postconditioning may enhance glycogen synthase kinase-3β activity, a downstream molecule of the phosphatase and tensin homolog deleted on chromosome 10/phosphatidylinositol 3-kinase/protein kinase B signaling pathway, which reduces caspase-3 expression to protect the brain against ischemic injury.
- [Show abstract] [Hide abstract] ABSTRACT: To evaluate the efficacy and safety of dexmedetomidine for emergence agitation after tonsillectomy in children. 120 ASA physical status I and II children, aged 5-14 years, undergoing anesthesia for tonsillectomy, were randomly divided into 3 groups: Placebo group, the low dexmedetomidine concentration group and the high dexmedetomidine concentration group. Before the entrance of the operating room (OR), all of the children received intravenous injection 40 μg kg(-1) midazolam to reduce anxiety at first, and then dexmedetomidine was given intravenously at an initial loading dose of 0.5 μg kg(-1) or 1 μg/kg over a 10-min period via a computer controlled infusion pump followed by a maintenance infusion of 0.2 μg kg(-1)h(-1) or 0.4 μg kg(-1)h(-1)over the surgery. The heart rate, SpO(2) and mean arterial blood pressure were recorded for each patient in both operation room and PACU. The designated time points: at the start of the anesthetic induction, at the discontinuation of inhalational agents, at first opening of eyes, at time to remove endotracheal tube were recorded. After patient arrival at the PACU, VAS score, RSS, the occurrence of emergence agitation were recorded every 5 min for the first 30 min and every 10 min for the next 30 min after endotracheal tube was removed. There was significant difference in the incidence of emergence agitation between Placebo group and the high concentration group when endotracheal tube was removed (P<0.05). There was significant difference in the VAS pain scores and in the RSS between three groups at the time of extubation, as well as 5 min and 10 min after extubation (P<0.05). Dexmedetomidine appears to be safe and effective to reduce the incidence of early emergence agitation in children after tonsillectomy. Initial loading dose of 1.0 μg kg(-1) followed by a maintenance infusion of 0.4 μg kg(-1)h(-1) is better choice for children received tonsillectomy.
- [Show abstract] [Hide abstract] ABSTRACT: The present study established a rabbit model of global cerebral ischemia using the 'six-vessel' method, which was reperfused after 30 minutes of ischemia. Rabbits received intravenous injection of propofol at 5 mg/kg prior to ischemia and 20 mg/kg per hour after ischemia until samples were prepared. Results revealed that propofol inhibited serum interleukin-8, endothelin-1 and malondialdehyde increases and promoted plasma superoxide dismutase activity after cerebral ischemia/reperfusion. In addition, cerebral cortex edema was attenuated with little neuronal nuclear degeneration and pyknosis with propofol treatment. The cross-sectional area of neuronal nuclei was, however, increased following propofol treatment. These findings suggested that propofol could improve anti-oxidant activity and inhibit synthesis of inflammatory factors to exert a protective effect on cerebral ischemia/reperfusion injury.
- [Show abstract] [Hide abstract] ABSTRACT: General anesthetics induce loss of consciousness by inhibiting ascending arousal pathways, and they interfere with gap junction electrical coupling. The present study aimed to determine whether inhibition of gap junction-mediated signaling could influence general anesthetic-induced loss of consciousness. The general anesthetics sevoflurane and propofol were used. Intracerebroventricular administration of carbenoxolone, a gap junction blocker, significantly decreased the time to loss of the righting reflex (P < 0.05), but prolonged the time to recovery of the reflex (P < 0.05). Moreover, intracerebroventricular administration of carbenoxolone increased the sensitivity to sevoflurane, with a leftward shift of the loss of righting reflex dose-response curve, and decreased the 50% effective concentration of sevoflurane. These results suggest that the gap junction blocker carbenoxolone enhances propofol and sevoflurane-mediated general anesthesia.
- [Show abstract] [Hide abstract] ABSTRACT: To investigate the effects of ligustrazine on acute lung injury induced by blunt chest trauma. This study was performed in the Animal Center of Renmin Hospital of Wuhan University, Wuhan, China between September 2009 and September 2010. Male Sprague-Dawley rats were randomly allocated into 4 groups: sham control group (group C, n=60), ligustrazine treatment group (group C+L, n=60), blunt chest trauma model group (group T, n=60), and the trauma plus ligustrazine treatment group (group T+L, n=60). The lung contusion was induced as previously described. Animals of the T+L group were intraperitoneally injected with ligustrazine. Acute lung injury was evaluated by histopathology of the lung, and apoptosis was determined by terminal dUTP nick-labeling. Pulmonary edema was estimated using Evans blue dye extravasation and wet/dry ratios of lung tissue. The expression of caspase-3, Bcl-2, and Bax in the lung, as well as blood plasma tumor necrosis factor (TNF)-alpha were also measured. The ligustrazine treatment significantly attenuated lung injury induced by blunt chest trauma, as shown by decreased apoptosis index, and pulmonary edema (p=0.04). The blood plasma TNF-alpha level after blunt chest trauma significantly deceased after the administration of ligustrazine (p=0.03). In addition, the ligustrazine treatment significantly alleviated the expression of caspase-3 (p=0.03), and increased the ratio of Bcl-2 to Bax (p<0.03). Ligustrazine effectively protects lung injury induced by blunt chest trauma, and the protective effects seem to be mediated by attenuation of cell apoptosis via an increased ratio of Bcl-2/Bax and decreased caspase-3 activity.
- [Show abstract] [Hide abstract] ABSTRACT: Diabetes mellitus is associated with decreased NO bioavailability in the myocardium. Ginsenoside Rb1 has been shown to confer cardioprotection against ischemia reperfusion injury. The aim of this study was to investigate whether Ginsenoside Rb1 exerts cardioprotective effects during myocardial ischemia-reperfusion in diabetic rats and whether this effect is related to increase the production of NO via enhancing eNOS expression in the myocardium. The myocardial I/R injury were induced by occluding the left anterior descending artery for 30 min followed by 120 min reperfusion. An eNOS inhibitor L-NAME or Rb1 were respectively administered 25 min or 10 min before inducing ischemia. Ginsenoside Rb1 preconditioning reduced myocardial infarct size when compared with I/R group. Ginsenoside Rb1 induced myocardial protection was accompanied with increased eNOS expression and NO concentration and reduced plasma CK and LDH (P < 0.05). Moreover, the myocardial oxidative stress and tissue histological damage was attenuated by Ginsenoside Rb1 (P < 0.05). L-NAME abolished the protective effects of Ginsenoside Rb1. It is concluded that Ginsenoside Rb1 protects against myocardium ischemia/reperfusion injury in diabetic rat by enhancing the expression of eNOS and increasing the content of NO as well as inhibiting oxidative stress.
- [Show abstract] [Hide abstract] ABSTRACT: Phosphocreatine (PCr) is an endogenous compound containing high-energy phosphate bonds. It has been confirmed that PCr is effective in preventing and treating cardiac and renal ischemia-reperfusion injury. In this study, rat cerebral ischemia-reperfusion injury models were constructed. Apoptotic cells in the cortex region were measured by TUNEL method. Malondialdehyde (MDA) content was detected by chromatometry, and calmodulin (CaM) activity was detected by ELISA. Compared with sham-operated group (sham group), TUNEL-positive cells, MDA, and level of CaM activity increased in ischemia-reperfusion group (I/R group) and PCr preconditioning group (PCr group); compared with I/R group, TUNEL-positive cells, MDA content, and level of CaM activity decreased in PCr group. This study indicated that PCr can decrease the morphological damage and the neuron apoptosis of the ischemia-reperfusion injury brain through attenuating abnormalities of calcium balance and production of oxygen free radicals.
- [Show abstract] [Hide abstract] ABSTRACT: The objective of the current study is to investigate whether ginsenoside Rb1, a major pharmacological extract of ginseng that could attenuate myocardial ischemia reperfusion (MI/R) injury in non-diabetic myocardium, can attenuate MI/R injury in diabetes that are more vulnerable to ischemic insult. Rats were divided into seven groups: (i) diabetic sham, (ii) diabetic, (iii) normal, (iv) diabetic + ginsenoside Rb1, (v) diabetic + wortmannin, (vi) diabetic + wortmannin + ginsenoside Rb1, (vii) diabetic sham + wortmannin. Ginsenoside Rb1 and/or wortmannin were administered prior to inducing MI/R (30 min of coronary artery occlusion followed by 120 min reperfusion). At the end of the experiment, postischemic myocardial infarct size was significantly higher in the diabetic untreated group as compared to normal (P < 0.05), accompanied with increased myocardial apoptosis, elevated plasma CK-MB and LDH release and reduced blood pressure. Ginsenoside Rb1 reduced infarct size, cardiomyocyte apoptosis and caspase-3 activity compared to the diabetic group. The cardioprotective effects of ginsenoside Rb1 were cancelled by wortmannin. Ginsenoside Rb1 significantly upregulated phosphorylated Akt expression, which was attenuated by wortmannin. Ginsenoside Rb1 exerts cardioprotective effects against MI/R injury in diabetic rats, which is partly through activation of phosphatidylinositol 3-kinase (PI3 K)/Akt pathway. Thus this study shows a novel pharmacological preconditioning with ginsenoside Rb1 in the diabetic myocardium.
- [Show abstract] [Hide abstract] ABSTRACT: A simple and rapid CZE method was established for the simultaneous determination of valienamine, acarbose and validamycin A, using a 20-kV CZE with the detection wavelength of 193 nm and 50 mM phosphoric acid-20 mM Tris (pH 5.3) as a running buffer. The calibration curves of valienamine, acarbose, and validamycin A showed a good linear relationship at a concentration range of 5-1000 microg/mL. The detection limits of valienamine, acarbose, and validamycin A were 0.3, 0.6, and 0.6 microg/mL, respectively, and the average recoveries of each of the above were 99.9, 99.5, and 100.3%. The method has been successfully applied for simultaneous determination of substrate and product in the process of preparation of valienamine.
Wu-han-shih, Hubei, China
- Department of Anesthesiology
Shanghai Institute of Pharmaceutical IndustryShanghai, Shanghai Shi, China