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ABSTRACT: Strontium stimulates cartilage matrix formation in vitro. However, the mechanisms governing these effects have not yet been extensively reported. In this study, chondrocytes were isolated from rat articular cartilage by enzymatic digestion and cultured for 24-72 h with 1-5 mM strontium. We investigated the effects of different concentrations of strontium on collagen content, type II collagen, insulin-like growth factor (IGF-1) and matrix metalloproteinase (MMP)-13 expression in rat cultured articular chondrocytes in vitro. The collagen content of the chondrocytes, determined as hydroxyproline, was measured by a colorimetry method. Type II collagen, IGF-1, and MMP-13 mRNA abundance and protein expression levels were determined by real-time polymerase chain reaction (real-time PCR) and western blot, respectively. The results showed that collagen content from the chondrocytes extracellular matrix increased with increasing strontium concentration. Moreover, 3 and 5 mM strontium strongly stimulated protein expression and mRNA levels of type II collagen and IGF-1. Conversely, MMP-13 expression in chondrocytes decreased dose-dependently with increasing strontium concentration. These results should provide insight into the ability of strontium to promote chondrocyte extracellular matrix synthesis. Strontium could promote collagen synthesis and suppress collagen degradation via the repression of MMP-13 expression.
Biological trace element research 03/2013; · 1.92 Impact Factor
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ABSTRACT: Background: Phosphatase and tensin homolog (PTEN) is a potent tumor suppressor gene that also plays a vital role in regulating fatty acid metabolism. Here we attempted to elucidate the role of PTEN in the regulation of fatty acid oxidation and the assembly and secretion of very low density lipoprotein (VLDL) in dairy cow liver. Methods: We transfected primary culture calf hepatocytes with adenovirus-mediated PTEN overexpression vector (AD-GFP-PTEN).PTEN-overexpressing hepatocytes and control hepatocytes were obtained. Results: Compared with controls, overexpression of PTEN significantly up-regulated CPT I, ACSL, HADH expression (p<0.05), which are all involved in fatty acid oxidation. At the same time, the expression of ApoB100 (p<0.01), ApoE (p<0.05) and MTP (p<0.01) increased. Therefore, the assembly and secretion of VLDL was enhanced (p<0.05). The expression of LDLR was slightly up-regulated, but there was no significant difference (p>0.05). To demonstrate that fatty acid metabolism was changed, we measured the concentrations of TG and VLDL. The concentration of TG was significantly decreased in hepatocytes (p<0.01), while the concentration of VLDL was significantly increased in the medium (P<0.05). Conclusions: Overexpressing PTEN enhanced fatty acid oxidation and assembly and secretion of VLDL. PTEN gene therapy could have therapeutic potential for fatty liver diseases of dairy cattle.
Cellular Physiology and Biochemistry 09/2012; 30(4):1005-1013. · 2.86 Impact Factor
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ABSTRACT: Red-colored bones were first found in Guishan goats in the 1980s, and they were subsequently designated red-boned Guishan goats. However, the difference remains unclear between the bone mineral density (BMD) or elemental composition in bones between red-boned Guishan goats and common Guishan goats. Analysis of femoral bone samples by dual-energy X-ray absorptiometry and inductively coupled plasma optical emission spectrometry revealed an increase in bone mineral density in the femoral diaphysis and distal femur of red-boned Guishan goats at 18 and 36 months of age. The data revealed that BMD increased in both the red-boned and common Guishan goats from 18 to 36 months of age. The data also indicated that the ratio of the BMD values of red-boned to common Guishan goats was higher at 36 months of age than they were at 18 months of age. Furthermore, the levels of calcium, phosphorus, magnesium, barium, zinc, manganese, and aluminum were significantly higher in red-boned Guishan goats than common Guishan goats at 18 and 36 months of age. The results indicate that the red-boned Guishan goats were linked to the elevated levels of mineral salts observed in the bones and that this in turn may be linked to the elevated BMD levels encountered in red-boned Guishan goats. These reasons may be responsible for the red coloration in the bones of red-boned Guishan goats.
Biological trace element research 05/2012; · 1.92 Impact Factor
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ABSTRACT: The major role of insulin-like growth factor-1 (IGF-1) in the liver is to mediate glucose uptake in hepatocytes to synthesize glycogen and maintain blood glucose homeostasis. In this study, to evaluate the role of IGF-1 on gluconeogenesis and nutrient metabolism in dairy cattle, pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase (PEPCK) expression and enzyme activity were evaluated in primary cultures of bovine hepatocytes treated with different concentrations of IGF-1 by quantitative polymerase chain reaction and spectrophotometry, respectively. The results showed that expression of PC and PEPCK were significantly lower in bovine hepatocytes by IGF-1 treatment in test group compare to the control group (P < 0.01). As IGF-1 concentration increased, PC and PEPCK enzyme activity in bovine hepatocytes decreased. Evaluating PC and PEPCK mRNA levels and enzyme activity may thus be useful to monitor subclinical ketosis in dairy cows.
Molecular and Cellular Biochemistry 03/2012; 362(1-2):87-91. · 2.06 Impact Factor
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ABSTRACT: The transition period is a severe challenge to dairy cows. Glucose supply cannot meet demand and body fat is mobilized, potentially leading to negative energy balance (NEB), ketosis, or fatty liver. Propionate produces glucose by gluconeogenesis, which depends heavily on the number and species of microbes. In the present study, we analyzed the rumen microbiome composition of cows in the transition period, cows with ketosis, and nonperinatal cows by terminal restriction fragment length polymorphism (TRFLP) analysis of 16S rRNA genes and quantitative PCR. TRFLP analysis indicated that the quantity of Veillonellaceae organisms was reduced and that of Streptococcaceae organisms was increased in rumen samples from the transition period and ketosis groups, with the number of Lactobacillaceae organisms increased after calving. Quantitative PCR data suggested that the numbers of the main propionate-producing microbes, Megasphaera elsdenii and Selenomonas ruminantium, were decreased, while numbers of the main lactate-producing bacterium, Streptococcus bovis, were increased in the rumen of cows from the transition period and ketosis groups, with the number of Lactobacillus sp. organisms increased after calving. Volatile fatty acid (VFA) and glucose concentrations were decreased, but the lactic acid concentration was increased, in rumen samples from the transition period and ketosis groups. Our results indicate that the VFA concentration is significantly related to the numbers of Selenomonas ruminantium and Megasphaera elsdenii organisms in the rumen.
Applied and environmental microbiology 01/2012; 78(7):2386-92. · 3.69 Impact Factor
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ABSTRACT: Red-colored bones were found initially in some Guishan goats in the 1980s, and they were designated red-boned goats. However, it is not understood what causes the red color in the bone, or whether the red material changes the bone geometry, architecture, and metabolism of red-boned goats. Pseudopurpurin was identified in the red-colored material of the bone in red-boned goats by high-performance liquid chromatography-electrospray ionization-mass spetrometry and nuclear magnetic resonance analysis. Pseudopurpurin is one of the main constituents of Rubia cordifolia L, which is eaten by the goats. The assessment of the mechanical properties and micro-computed tomography showed that the red-boned goats displayed an increase in the trabecular volume fraction, trabecular thickness, and the number of trabeculae in the distal femur. The mean thickness, inner perimeter, outer perimeter, and area of the femoral diaphysis were also increased. In addition, the trabecular separation and structure model index of the distal femur were decreased, but the bone mineral density of the whole femur and the mechanical properties of the femoral diaphysis were enhanced in the red-boned goats. Meanwhile, expression of alkaline phosphatase and osteocalcin mRNA was higher, and the ratio of the receptor activator of the nuclear factor kappa B ligand to osteoprotegerin was markedly lower in the bone marrow of the red-boned goats compared with common goats. To confirm further the effect of pseudopurpurin on bone geometry, architecture, and metabolism, Wistar rats were fed diets to which pseudopurpurin was added for 5 months. Similar changes were observed in the femurs of the treated rats. The above results demonstrate that pseudopurpurin has a close affinity with the mineral salts of bone, and consequently a high level of mineral salts in the bone cause an improvement in bone strength and an enhancement in the structure and metabolic functions of the bone.
PLoS ONE 01/2012; 7(5):e37469. · 4.09 Impact Factor
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Jianguo Wang,
Xiaoyan Zhu, Xiaobing Li,
Wei Wang,
Xiaoxu Wang,
Lei Liu,
Qinghua Deng,
Ge Bai,
Jianfa Wang,
Haihua Feng,
Zhe Wang,
Guowen Liu
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ABSTRACT: Chondrocytes from the lateral trochlear ridge of the distal femur taken from 1-day-old piglets were cultured in medium supplemented with 0, 7.8, 15.6, 31.2, and 62.5 μmol/L copper. Insulin-like growth factor-1 (IGF-1) and IGF-binding protein 3 (IGFBP-3) levels in culture medium were determined by radioimmunoassay. DNA synthesis in chondrocytes was measured by tritiated thymidine ((3)H-TdR) incorporation. Proliferation-promoting activity and incorporation of (3)H-TdR in chondrocytes were increased in all culture media supplemented with copper and 15% fetal calf serum (FCS). The contents of IGF-1 and IGFBP-3 were also enhanced significantly in culture media containing 15% FCS and supplemented with copper at 15.6, 31.2, and 62.5 μmol/L. The optimal copper concentration for promoting chondrocyte proliferation and autocrine secretion of IGF-1 and IGFBP-3 was 31.2 μmol/L.
Biological trace element research 12/2011; 144(1-3):588-96. · 1.92 Impact Factor
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ABSTRACT: Dairy cows experience an increased demand for glucose to support milk production. However, negative energy balance is a common condition in peripartum cows. In response, fat mobilization provides non-esterified fatty acids (NEFAs) for oxidation in the liver to generate ATP. To investigate the effects of NEFAs on gluconeogenesis, the expression and enzyme activity of pyruvate carboxylase (PC) and phosphoenolpyruvate carboxylase (PEPCK) in cultured bovine hepatocytes were evaluated by quantitative polymerase chain reaction and spectrophotometry, respectively. The results showed that PC and PEPCK mRNA levels were marked decreased when the NEFAs concentrations exceeded 0.5 and 1.5 mmol/l, respectively. The PC and PEPCK enzyme activity showed significantly decreased when the NEFAs concentrations exceeded 1.5 and 0.5 mmol/l, respectively. These findings indicate that high circulating levels of NEFAs inhibit hepatocyte gluconeogenesis, thereby promoting negative energy balance.
Molecular and Cellular Biochemistry 08/2011; 359(1-2):385-8. · 2.06 Impact Factor
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Zhigang Zhang, Xiaobing Li,
Hongbin Wang,
Changming Guo,
Li Gao,
Lei Liu,
Ruifeng Gao,
Yi Zhang,
Peng Li,
Zhe Wang,
Yanfei Li,
Guowen Liu
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ABSTRACT: Serum concentrations of sodium, potassium, magnesium, and iron were measured in dairy cows with subclinical ketosis. Compared with healthy cows, the subclinically ketotic cows had significantly higher levels of non-esterified fatty acids and β-hydroxybutirate in serum and significantly lower levels of blood glucose (p < 0.01). No significant differences were observed, suggesting that the mineral elements measured are not involved in the pathogenesis of subclinical ketosis.
Biological trace element research 07/2011; 144(1-3):525-8. · 1.92 Impact Factor
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Yi Zhang, Xiaobing Li,
Guowen Liu,
Zhe Wang,
Tao Kong,
Jiajia Tang,
Peng Zhag,
Wei Yang,
Dongna Li,
Lei Liu,
Guanghong Xie,
Jianguo Wang
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ABSTRACT: Immunoassays for heavy metals offer an alternative approach to traditional techniques for detection of mercury. In this study, a mercury-chelate was prepared with 1-(4-aminobenzyl) ethylenediamine-N,N,N',N'-tetraacetic acid (aminobenzyl-EDTA). The resulting complex was linked to keyhole limpet hemocyanin (KLH) or bovine serum albumin via the amino group and used as the immunizing antigen or detection antigen, respectively. BALB/c mice were immunized with KLH-aminobenzyl-EDTA-Hg and spleen cells from BALB/C mice were fused with Sp2/0 cells. One cell line (5F7) produced monoclonal antibodies with preferential selectivity and sensitivity for aminobenzyl-EDTA-Hg. This cell line had an affinity constant of 4.31 × 10(9) L/mol and its cross-reactivity (CR) with other metals was <2%. The antibody was used for competitive indirect ELISA (CI-ELISA) for Hg(2+) measurements. The detection range was 0.087-790.4 μg/L and the lower limit of detection was 0.042 μg/L. The concentrations of mercury in environmental water samples obtained by CI-ELISA correlated well with graphite furnace atomic absorption spectrometry (GFAAS), and the mean recovery was 88.82% to 104.64%. These results indicate that this method could be used for monitoring mercury of water.
Biological trace element research 03/2011; 144(1-3):854-64. · 1.92 Impact Factor
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ABSTRACT: The major role of insulin and the insulin receptor (InsR) in the liver is to mediate glucose uptake into hepatocytes to synthesize glycogen and to maintain blood glucose homeostasis. In this study, we investigated the effects of high insulin concentrations on InsR gene expression in calf hepatocytes cultured in vitro. After the cells were cultured for 72 h, insulin was added to the culture solution at final concentrations of 0, 1, 10, 100 or 1000 nM. InsR mRNA expression was determined by semi-quantitative RT-PCR. The results showed that InsR mRNA expression in hepatocytes, adjusted for β-actin expression, decreased dose dependently with increasing insulin concentration. InsR mRNA expression was similar at 1 and 10 nM insulin, but was significantly lower than that in the control. InsR expression was similar at 100 and 1000 nM insulin, but was significantly lower than that in the control, 1 and 10 nM insulin groups. These data suggest that high concentrations of insulin significantly repress InsR mRNA expression in calf hepatocytes, and this inhibition occurs in a dose-dependent manner. Further studies are needed to investigate the mechanisms underlying these effects of insulin.
Cellular Physiology and Biochemistry 01/2011; 27(6):637-40. · 2.86 Impact Factor
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Xiaoyan Zhu,
Jianguo Wang,
Guanghong Xie,
Haihua Feng, Xiaobing Li,
Lei Liu,
Xiaoxu Wang,
Dongna Li,
Zhaoxi Liu,
Jian Qian,
Zhe Wang,
Guowen Liu
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ABSTRACT: This experiment was conducted to measure the effect of copper supplementation on TGF-β gene expression in chondrocytes of newborn pigs. Chondrocytes were cultured in media containing 15% fetal calf serum supplemented with 0, 15.6, 31.2, and 62.5 μmol/L copper in 90-mm culture plate. Total RNA was isolated from chondrocytes, and TGF-β cDNA was synthesized, amplified, and sequenced. The expression level of TGF-β was examined by reverse transcription polymerase chain reaction. The results showed that the sequence of the cloned TGF-β gene was 99.4% identical to that in GenBank. The expression of TGF-β increased in culture media added with final concentration of 15.6, 31.2, and 62.5 μmol/L copper. In this study, the optimal copper concentration and optimal culture time for the highest level of TGF-β expression were 31.2 μmol/L and 48 h, respectively.
Biological trace element research 01/2011; 143(3):1461-9. · 1.92 Impact Factor
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ABSTRACT: Ketosis in dairy cows can lead to poor reproductive success and decreased milk production. Since the serum concentrations of copper (Cu) and zinc (Zn) are closely associated with the health status of cows, we investigated whether serum concentrations of Cu and Zn differed in dairy cows with subclinical ketosis and healthy dairy cows. Blood samples of 19 healthy dairy cows and 15 subclinically ketotic dairy cows were collected from three farms, and the concentrations of β-hydroxybutyrate (BHBA), glucose, non-esterified fatty acids (NEFA), Cu, and Zn were determined. Subclinically ketotic dairy cows had significantly higher BHBA and NEFA levels (p < 0.01) and lower glucose (p < 0.01) than healthy dairy cows. Likewise, serum concentrations of Zn were significantly decreased (p < 0.05) in dairy cows with subclinical ketosis. There was no significant difference observed for serum Cu concentration between healthy and subclinically ketotic dairy cows. This study suggests that a decreased serum Zn concentration could be a cause of decreased reproductive performance in subclinically ketotic dairy cows.
Biological trace element research 12/2010; 138(1-3):8-12. · 1.92 Impact Factor
