Objective To investigate the expression of aquaporin-1( AQP-1) in pleural mesothelial cells ( PMCs) and the influence of glucose thereupon. Methods Rat PMCs were isolated, cultured, and divided into two groups, ie. a glucose group, cultured with glucose of different concentrations for 24 hours,and a control group, cultured in D-MEM/ F-12 medium. The 100 mmol / L glucose group was administered at the time points of 6, 12, 18, and 24 hours respectively. RT-PCR and Western blotting were used to analyze the mRNA and protein expression of AQP-1. Results The absorbance values of AQP-1 protein expression were 54. 02 ±4. 61, 127. 84 ±9. 41, and 231. 62 ±22. 63, respectively in the PMCs treated with glucose of the concentrations of 50, 100, and 200 mmol / L, all significantly higher than those in the control group( 22. 45 ±2. 16, all P lt; 0. 01) . The absorbance values of AQP-1 protein expression were 24. 68 ±2. 56, 58. 68 ±3. 67, 89. 61 ±6. 62, and 113. 41 ±7. 65 in the PMCs treated with glucose of the concentration of 100 mmol / L after 6, 12, 18, and 24 hours, all significantly higher than those in the control group ( 11. 81 ±1. 45, P lt;0. 01) .Conclusions Glucose induces the expression of AQP-1 mRNA and protein. AQP-1 participates in the pleural fluid formation.
Objective To investigate the effects of expression of TNFα mRNA on glucose uptake in both the liver and skeletal muscle after endotoxemia. Methods In the mice with intraperitoneal injection of lipopolysaccharide (LPS), the changes of TNFα level of plasma and uptake of 2-deoxyglucose (2-DG) in the isolated soleus muscle and hepatic tissues were determined, then the reinstatement of glucose uptake by injecting TNF-McAb for 3 days was also observed. In addition, changes of TNFα mRNA expression of liver were evaluated. Results The expression of TNFα mRNA in the liver showed markedly increased in the first 3 hours post endotoxemia and remaind high for 3 days, and the plasma TNFα level paralleled with TNFα mRNA expression of liver also was elevated. The basal uptake of 2-DG both in muscle and liver were markedly increased, but the stimulated 2-DG uptake with insulin was greatly reduced as compared with the control. In addition, these abnormalities of 2-DG uptake can be partially corrected by neutralization of the circulatory TNFα by administration of TNF-McAb. Conclusion The disorders of glucose uptake of the liver and the muscle due to the overexpression of TNFα mRNA and elevated circulatory TNFα level may be the mechanism of insulin resistance after endotoxemia.
Objective To investigate the effect of glucagon-like peptide-1(GLP-1) on impaired glucose tolerance due to stress postoperatively. Methods The rats were allocated randomly to one of three groups, group Ⅰ was subdivided into group Ⅰg which received an intravenous glucose load (0.5 g/kg glucose), and group Ⅰglp which received the same glucose load with GLP-1 (0.3 nmol/kg) during intravenous glucose tolerance test (IVGTT). Rats in group Ⅱg and group Ⅱglp in group Ⅱ were infused respectively the same intravenous glucose tolerance test as group Ⅰ on the first, third and fifth day after 65% liver resection. And rats in group Ⅲ were injected the same glucose load with GLP-1 (0.45 nmol/kg) during IVGTT on the first day after hepatectomy. The peak glucose levels, glucose levels at 30 minutes and the area under the curve (AUC0-30) were investigated among groups. Results The peak glucose levels, glucose levels at 30 minutes and AUC0-30 were significantly lower in group Ⅰglp than those in group Ⅰg. And the values were significantly higher in group Ⅱg than those in group Ⅰg on the first, third and fifth day after operation. There was no significant difference between group Ⅱglp and group Ⅱg in the peak glucose levels on the first day after liver resection, but the peak glucose levels and AUC0-30 were significantly lower in group Ⅲ than those in group Ⅱg and group Ⅱglp, and the glucose levels at 30 minutes were significantly lower in group Ⅲ than those in group Ⅱg too on the first day. The peak glucose levels were significantly lower in group Ⅱglpthan those in group Ⅱg on the third and fifth postoperative day and in group Ⅱglp on the first day too, and the glucose levels at 30 minutes and AUC0-30 were also significantly lower in group Ⅱglp than those in group Ⅱg, but they were similar between group Ⅱglp and group Ⅰg. Conclusion Glucose intolerance is a feature of stress after hepatectomy, and GLP-1, injected in conjunction with the IVGTT, increased the clearance of glucose. The contribution of GLP-1 to reducing blood glucose was decreased significantly at early phase postoperatively, but its action was enhanced by the way of dosage dependence. The action of GLP-1 was enhanced with the degree of stress reduction and then returned to normal.
ObjectiveTo study the effects of Ghrelin for glucose metabolism and insulin sensitivity of L6 rat myoblasts in palmitic acid induced, and to explore its possible mechanisms. MethodsThe L6 rat myoblasts were cultured until differentiation, then using palmitic acid(0.3 mmol/L) for 16 hours. The experimental group was treated with different doses of Ghrelin(1, 10, and 100 nmol/L) for 8 hours, then the glucose uptake was detected by using glucose oxidase peroxidase method(GOD-POD), the cell membrane glucose transporter 4(GLUT-4) protein staining was observated under confocal microscopy, and the expressions of total protein kinase B(Akt), phosphorylated protein kinase B(pAkt), total glycogen synthase kinase-3β(GSK-3β), and phosphorylated glycogen synthase kinase-3β(pGSK-3β) were detected by using immunoblotting(Western blot). ResultsGhrelin enhanced the glucose uptake of L6 rat myoblasts with insulin resistance, the cell membrane Glut-4 stain was deepen, the expressions of pAkt and pGSK-3βprotein increased, and this effect could be PI3K blocker(LY294002) eliminated. ConclusionGhrelin promotes the glucose uptake of L6 rat myoblasts through PI3K/Akt/GSK-3βsignaling pathway, so as to improve the sensitivity of insulin in L6 rats muscle cells.
Objective To observe the different effect such as high concentration of glucose and high concentration of insulin on GLUT1 of Rabbit Retinal Muuml;ller Cell in vitro. Methods Rabbit retinal Muuml;ller cells were cultured in vitro with suspended constitution，which were divided as the following groups: common control group，high glucose group，insulin group，high glucose combined insulin group. Laser confocal microscope combined with immunocytochemical and fluorescence staining method to quantitatively analyze the expression condition of GLUT1. Results The expression of GLUT1 has been enhanced obviously by high glucose and high insulin，which locates mainly in the cytoplasm that near to the nucleus. Conclusion Rabbit retinal Muuml;ller cells can express GLUT1，and the expression of GLUT1 can be reinforced by high glucose and high insulin. （Chin J Ocul Fundus Dis，2008，24：265-267）
Objective To observe the effects of high concentr at ion glucose on the calcium-activated potassium channel of rabbits′ retinal Müller cells. Methods The rabbits′retinal Müller cells were cultured in vitro under the condition of high concentration glucose, and identified by immunohistochemical staining and transmission electron microscopy. Patch-clamp technique was used to observe the changes of the calcium-activated potassium channel of retinal Müller cells caused by high concentration glucose at different time.Results High concentration glucose could inhibit the calcium-activated potassium channel of cultured retinal Müller cells in a time-dependent manner. Conclusion High concentration glucose may reduce the biological functions of Müller cells by inhibiting calcium-activated potassium channel. (Chin J Ocul Fundus Dis，2003，19：164-167)
Objective To assess the differences between a glucose meter and autoanalyzer at home and broad.Method MEDLINE, CNKI, FMJS, and CBM were searched electronically (1995 to May, 2008). The statistical analysisof included studies was performed according to the Cochrane systematic reviews method. Result Twenty four studies, including 11 English records and 19 Chinese records involving 4 963 specimens, were included in this study. Meta-analysis showed us the blood glucose values of Abbott, Roche, and Johnson abroad subgroups are higher than the laboratory method, and their WMD (95%CI) are 0.57 (0.34,0.80), 0.43 (0.04,0.81), 0.41 (0.11,0.71). The blood glucose values of the Abbot and Roche domestic subgroups are comparable to the laboratory method [WMD= 0.60, 95%CI (– 0.79, 1.99); WMD= – 0.13, 95%CI (– 0.56, 0.29)]. The blood glucose value of the Johnson domestic subgroup is lower than laboratory method [WMD= – 0.95, 95%CI (– 1.42, – 0.48)]. Conclusion The results of the abroad studies are relatively consistent, and the blood glucose values of all abroad subgroups are higher than laboratory method. The domestic studies are different because of other factors.
ObjectiveTo investigate the prevalence of impaired glucose regulation (IGR) and IGR combined with cardiovascular risk factors in rural areas of Chengdu City. MethodsFrom February to October 2010, we randomly sampled 1 016 patients in a rural community 100 kilometers away from the city center as the study subjects. The investigation was carried out by using questionnaire survey, physical examination and laboratory tests. The standard 75 g oral glucose tolerance test was used. ResultsA total of 1 016 subjects were investigated, among whom there were 431 males and 585 females with an average age of 56 years old. Of these subjects, 333 were diagnosed to have IGR with a rate of 32.77% (333/1 016). The age-adjusted standardized prevalence of pre-diabetes in rural areas in Chengdu was 32.52% (336/1 016), and the male and female prevalence were respectively 30.63% (132/431) and 34.36% (201/585) without significant difference (χ2=1.569，P=0.210). Impaired glucose tolerance (IGT) was the most common type of glycometabolism abnormality. Women had a significantly higher prevalence of IGT than men. In IGR population, major cardiovascular risk factors were overweight and obesity (40.8%), high low density lipoprotein cholesterol (38.4%), high triglyceride (30.3%), hypertension (23.7%), smoking (24.3%), and drinking alcohol (23.7%). The stratified analysis showed that the prevalence of overweight, obesity and low high density lipoprotein cholesterol in female was significantly higher than that in males, while the prevalence of smoking and drinking alcohol was significantly higher in males. ConclusionIn rural areas, the prevalence of pre-diabetes is high and complicated with multiple cardiovascular risk factors.
Objective To elucidate whether glucose transporters-4 （GLUT-4） takes part in glucose uptake of mesenchymal stem cells （MSCs） and whether Akt gene improves translocation and expression of GLUT-4 in MSCs under hypoxic environment ex vivo. Methods MSCs, transfected by Akt gene and no, were cultured with normoxia (5% CO2) or hypoxia (94%N2, 1%O2 and 5% CO2) at 37 ℃ for 8 h. Glucose uptake was assayed by using radiation isotope 2-［3H］-deoxy-Dglucose (3H-G) and the expression of GLUT-4 protein and mRNA was assayed by immunocytochemistry, Western blot and RT-PCR, respectively. Results ①3 H-G intake of MSCs was significantly increased in hypoxiatransfection group than that in hypoxia-non-transfection 〔（1.39±0.13） fold, P＜0.05〕, but which was lower than that in normoxia-non-transfection group, P＜0.05. ②GLUT-4 was expressed by MSCs under any conditions. Compared with normoxia-non-transfection group, hypoxia decreased the expressions of GLUT-4 mRNA and protein significantly (P＜0.05). ③Compared with hypoxianontransfection group, the expression of GLUT-4 〔mRNA（1.756±0.152） fold, total protein in cell （1.653±0.312） fold, protein in plasma membrane （2.041±0.258） fold〕 was increased in hypoxia-transfection group significantly (P＜0.05), but which was lower than that in normoxianontransfection group (P＜0.05). ④There was significantly positive relation between 3H-G intake and GLUT-4 protein expression in plasma membrane (r=0.415, P=0.001).Conclusion GLUT-4 may take part in glucose uptake of MSCs, and the capability of Akt gene to improve MSCs anti-hypoxia may be finished by its role in increasing the expression and translocation of GLUT-4.
Age-related macular degeneration (AMD) involves dysregulation of the innate immune response of complement and mononuclear phagocytes and abnormalities of local microglia. When microglia transition from a resting state to an active state, their metabolic pathway also changes, known as "metabolic reprogramming", and their glucose metabolic reprogramming is a key factor in the pathogenesis of AMD, involving multiple signaling pathways. Including phosphatidylinositol 3-kinase-serine threonine kinase-rapamycin target, adenylate activated protein kinase and hypoxia-inducing factor 1 pathway. These metabolic changes regulate the inflammatory response, energy supply, and neuroprotective functions of microglia. Therapeutic strategies to regulate the reprogramming of glucose metabolism in microglia have achieved initial results. Future studies should further explore the mechanisms of microglia metabolic regulation to develop new targeted drugs and intervene in the treatment of AMD through anti-cellular aging pathways.