Objective To study the therapeutic effect of Roux-en-Y gastric bypass （RYGB） on type 2 diabetes mellitus （T2DM） rats and explore the possible mechanism of vaspin in RYGB on T2DM. Methods Twenty SD rats with T2DM and 20 age- and sex-matched normal SD rats were randomly divided into 4 groups according to the random digits table：T2DM-RYGB group， T2DM-sham operation （SO） group，RYGB group，and SO group，10 rats in each group. Fasting plasma glucose （FPG） level，serum insulin （INS） level，vaspin level，and homeostasis model of insulin resistance （HOMA-IR） were determined before operation and on week 4，8 after operation，respectively．At the same time，the correlation between vaspin and the indicators （FPG，INS，or HOMA-IR） was analyzed．Results Compared the indicators after operation with before operation，the FPG level，INS level，vaspin level，and HOMA-IR were not significantly different between the T2DM-RYGB group and T2DM-SO group （P＞0.05） or between the RYGB group and SO group （P＞0.05），but the FPG level，INS level，vaspin level，and HOMA-IR in the T2DM-RYGB group and T2DM-SO group were significantly higher than those in the RYGB group （P＜0.05） and SO group （P＜0.05），respectively. On week 4 after operation，the FPG level，INS level，vaspin level，and HOMA-IR decreased in the T2DM-RYGB group，except for the FPG level，the other indexes had no significant differences as compared with the values before operation. On week 8 after operation，the FPG level，INS level，vaspin level，and HOMA-IR further decreased in the T2DM-RYGB group，there were significant differences of these indicators between before operation and on week 8 after operation. Compared the indicators after operation with before operation，the FPG level，INS level，vaspin level，and HOMA-IR were not statistically significant （P＞0.05） in the T2DM-SO group，RYGB group，or SO group. The changes in serum vaspin level correlated positively with those in INS and HOMA-IR before operaion and on week 4，8 after operaion in the T2DM-RYGB group and T2DM SO group rats （P＜0.05），respectively. Conclusions RYGB surgery has a therapeutic effect on T2DM rats，and serum vaspin level decreases and insulin resistance is improved after RYGB surgery，which may be one of the mechanisms of the treatment for T2DM.
ObjectiveTo investigate the possible mechanism of the improvement of type 2 diabetes mellitus with insulin resistance of skeletal muscles after Roux-en-Y gastric bypass surgery (RYGB). MethodsThirty GK rats were randomly divided into GK-RYGB group, sham operation group (GK-SO group), and control group (GK-control group); in addition, 10 Wistar rats served as normal control group.On day 28, the animals were sacrificed.The ghrelin concen-tration and PI3Kp85α, Akt/PKB, and GLUT4 levels were measured by ELISA, Western blot, and real-time PCR me-thods, respectively. Results①Compared with the GK-SO group and GK-control group, the plasma ghrelin levels were significantly increased in the normal control group (P < 0.01) and GK-RYGB group (P < 0.01).②Compared with the GK-SO group and GK-control group, p-/t-PI3Kp85α, p-/t-Akt/PKB, and m-/t-GLUT4 proteins were significantly incre-ased in the normal control group (P < 0.01, P < 0.05, and P < 0.01, respectively) and GK-RYGB group (P < 0.01, P < 0.05, and P < 0.01, respectively).③Compared with the GK-SO group and GK-control group, PI3Kp85α, Akt, and GLUT4 mRNA were significantly increased in the normal control group (P < 0.01, P < 0.05, and P < 0.05, respectively) and GK-RYGB group (P < 0.01, P < 0.05, and P < 0.05, respectively). ConclusionRYGB could elevate the ghrelin level obviously and upregulate PI3Kp85α, Akt/PKB, and GLUT4 levels and thus improve the insulin resistance of skeletal muscles of rats with T2DM.
ObjectiveTo study effect of expression levels of serum inflammatory factors and insulin receptor substrate(IRS)-1/2 in visceral adipose tissue after Roux-en-Y gastric bypass(RYGB) on type 2 diabetes mellitus(T2DM) rats, and explore possible mechanism in treatment of T2DM. MethodsThe T2DM rats models were established, which were divided into 3 groups by intervention: T2MD-RYGB group(n=14), T2MD-sham operation(T2MD-SO) group(n=10), and T2MD group(n=10), and 10 normal rats were selected as control group. The rats of the T2MD-RYGB group were received the RYGB, and of the T2MD-SO group were received transection and reanastomosis of the gastroin-testinal tract. The fasting plasma glucose(FPG), fasting insulin(FINS), C-reaction protein(CRP), tumor necrosis factor-α(TNF-α), free fatty acid(FFA), homestasis model assessment for insulin resistance(HOMA-IR), adipose tissue insulin resistance(Adipo-IR) were tested respectively before operation and on week 1, 4, 8 after operation(synchronous detec-tion of rats with or without surgical intervention). The IRS-1 and IRS-2 protein contents of the rat epididymal adipose tissue were tested on week 8 after operation. ResultsThe FPG, FINS, CRP, TNF-α, FFA levels, and HOMA-IR, Adipo-IR indexes in the T2DM rats were significantly higher than those in the normal rats(P < 0.05) before operation, the above indicators on week 4, 8 after operation were significantly lower than those before operation in the T2MD-RYGB group(P < 0.05). The differences of changes among the other groups were not statistically significant(P > 0.05). The IRS-1 and IRS-2 protein expressions in the adipose tissue of the rats were significantly increased in the T2MD-RYGB group as compared with these indicators in the T2MD group and T2MD-SO group(P < 0.05), but which were significantly lower than those in the control group(P < 0.05). ConclusionsRYGB could increase IRS-1/2 expression levels in adipose tissue, which could enhance insulin sensitivity, decrease serum inflammatory factors levels, and improve insulin resistance ultimately. This might be one of the mechanisms in treatment of T2DM.
ObjectiveTo research the change and significance of Ghrelin and Visfatin in plasma after Roux-en-Y gastric bypass surgery (RYGB) in type-2 diabetes (T2DM) rats. MethodsThirty healthy Sprague Dawley (SD) rats (8 weeks) were divided into T2DM group (n=22) and blank control group (CSO group, n=8). Then rats of T2DM group were fed with high calorie and high sugar diet for 6 weeks, following by one dose of streptozotocin via intraperitioneal injection. Finally, there were 18 T2DM rats were successfully established. Then those 18 T2DM rats were divided into two groups:RYGB group (n=10) and sham operation group (DSO group, n=8). Rats of RYGB underwent RYGB, rats of DSO group and CSO group underwent sham operation. Levels of fasting serum glucose (FBG), fasting serum insulin (FINS), Ghrelin, and Visfatin of rats in 3 groups were detected by enzyme-linked immunoassay (EIA) before and 4 weeks after operation, and calculating the lee index and insulin sensitivity index (ISI). ResultsIn RYGB group, compared with before operation, the body weight, lee index, levels of FBG, FINS, and Visfatin decreased after 4 weeks after operation (P < 0.050), but level of ISI and Ghrelin increased (P < 0.050), while there was no significant difference in body weight, body length, lee index, ISI, levels of FBG, FINS, Ghrelin, and Visfatin in DSO and CSO group before and 4 weeks after operation (P > 0.050). In addition, there was statistical difference among the 3 groups in difference before and after operation of Ghrelin and Visfatin, the difference before and after operation of Ghrelin and Visfatin was larger than those of DSO group and CSO group (P < 0.050), but the difference was not significant differed between DSO group and CSO group (P > 0.050). ConclusionsThe increase of plasma Ghrelin and the decrease of Visfatin play important role in the mechanism after RYGB in treatment of T2DM rats.
ObjectiveTo verify the expression change of insulin-like growth factor-Ⅰ (IGF-Ⅰ) protein and its mRNA before and after Roux-en-Y gastric bypass surgery (RYGB) in obese rats, and to investigate the relationship between the expression of IGF-Ⅰ and proliferation/apoptosis of adipose cells. Methods① Seventy male SD rats were raised at the SPF level circumstance and were randomly divided into control group (NC group, 10 rats) and high fat diet group (60 rats). Rats of high fat diet group were given specific high fat formula diet, rats of NC group were given particular formula diet. After 6 weeks, the body weights of the rats in high fat diet group were measured, and the 20 rats of top weight were selected. The 20 obese rats were randomly divided into 2 groups:gastric bypass (GB) group (n=10) and sham-operation group (SO group, n=10). RYGB were administered to the rats of GB group, and for rats of SO group, sham operations were performed. Rats of NC group did not receive any surgery. Inguinal adipose tissues[represented the subcutaneous adipose tissue (SAT)] and epididymal adipose tissues[on behalf of visceral adipose tissue (VAT)] were taken during operation in rats of GB group and SO group respectively (0.5 g), and 12 weeks after operation in all rats of three groups. The expressions of IGF-Ⅰ protein and its mRNA in adipose tissue were detected by Western blot and real-time fluorescence quantitative PCR. ② Transfection experiment. SAT cells were divided into blank control group (BC group, without transfection), IGF-Ⅰ(+) group (gene overexpression group), IGF-Ⅰ(+) empty vector group, IGF-Ⅰ(-) group (gene silencing group), and IGF-Ⅰ(-) empty vector group. Cells were transfected with corresponding vectors with 3 duplicated holes of each group. Cell viability and apoptosis assays were carried out in 48 hours after transfection. Expressions of protein kinase B (AKT), phosphorylated protein kinase B (p-AKT), phosphoinositide 3-kinase (PI3K), and phosphorylated phosphoinositide 3-kinase (p-PI3K) were detected by Western blot meanwhile. ③ Wortmannin experiment. SAT cells were divided into Wortmannin (+) IGF-Ⅰ(+) group, Wortmannin (+) IGF-Ⅰ(-) group, Wortmannin (-) IGF-Ⅰ(+) group, and Wortmannin (-) IGF-Ⅰ(-) group, which were transfected with corresponding vectors for 24 hours, then adding Wortmannin (0.1 mmol/L). After 24 hours, the expression levels of AKT, p-AKT, p-PI3K, PI3K, and GAPDH were detected by Western blot. Results① PCR results showed that, in SAT, compared with preoperative GB group, the expression levels of IGF-Ⅰ mRNA and its protein in postoperative GB group were both lower (P < 0.01). However, the expression levels of IGF-Ⅰ mRNA and its protein between preoperative SO group and postoperative SO group showed no significant difference (P > 0.05). In VAT, the expression levels of IGF-Ⅰ mRNA and its protein in 5 groups showed no significant difference (P > 0.05). ② The MTT results showed that, IGF-Ⅰ(+) group harbored stronger proliferation abilities compared with its negative control group (P=0.04), whereas IGF-Ⅰ(-) group had lower abilities compared with its negative control group (P=0.04). The results of flow cytometry assay showed that, the apoptosis rate of IGF-Ⅰ(+) group was lower (P=0.04) than that of the corresponding negative control group, and it was higher in IGF-Ⅰ(-) group than that of the corresponding negative control group (P=0.04). ③ Compared with IGF-Ⅰ(+) empty vector group, p-PI3K/PI3K ratio (P=0.03) and p-AKT/AKT (P=0.04) ratio of IGF-Ⅰ(+) group were increased; compared with IGF-Ⅰ(-) empty vector group, p-PI3K/PI3K ratio (P=0.04) and p-AKT/AKT ratio (P=0.04) of IGF-Ⅰ(-) group were decreased. The p-AKT/AKT ratio of Wortmannin (-) IGF-Ⅰ(+) group was higher (P < 0.05) than that of Wortmannin (+) IGF-Ⅰ(+) group; the p-AKT/AKT ratio of Wortmannin (-) IGF-Ⅰ(-) group was lower than that of Wortmannin (-) IGF-Ⅰ(+) group (P < 0.05). ConclusionsIGF-Ⅰ is involved in the accumulation of subcutaneous fat in rats. RYGB can significantly reduce the expression levels of IGF-Ⅰ mRNA and its protein in subcutaneous fat of rats, so as to achieve the effect of weight loss.