内脏脂肪组织沉默信息调节因子1在高脂诱导西藏小型猪胰岛素抵抗中的表达研究

目的:探讨内脏脂肪组织沉默信息调节因子1(Sirt1)在高脂诱导西藏小型猪肥胖和胰岛素抵抗中的表达。方法:12只雄性西藏小型猪,随机分为正常对照组(NC)和高脂组(HFC),每组6只。造模16周后,测量空腹体重、体质量指数(BMI),并取前腔静脉血,测量总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)和高密度脂蛋白胆固醇(HDL-C),计算动脉硬化指数(AI);同时,进行静脉糖耐量实验。在动物进行安乐死后,检测内脏脂肪率,并取内脏脂肪组织进行病理组织学观察和脂肪细胞直径大小分析,并采用RT-PCR法观察脂肪组织中Sirt1、胰岛素样生长因子-1(IGF-1)、葡萄糖转运蛋白4(GLUT4)、过氧化物酶体增殖物激活受体γ(PPARγ)、过氧化物酶体增殖活化受体γ辅助活化因子1α(PGC-1α)、叉头框蛋白O1(FoxO1)、脂肪分解相关基因激素敏感性脂肪酶(HSL)及脂肪合成相关基因脂肪酸合成酶(FASN)的mRNA水平变化。结果:与NC组比较,HFC组体重、BMI指数、TC、LDL-C、HDL-C、AI和内脏脂肪率均显著升高(P<0.05,P<0.01);同时,糖耐量曲线...

Expression of Sirtuin 1 in visceral adipose tissue in Tibetan mini-pigs with obesity and insulin resistance induced by high fat/cholesterol diet

Objective: To investigate the role of Sirt1 in visceral adipose tissue in Tibetan mini-pigs with obesity and insulin resistance induced by high fat/cholesterol diet. Methods: Twelve male Tibetan mini-pigs were divided into 2 groups randomly: normal control (NC) group, high-fat/cholesterol (HFC) diet group, 6 in each group. After 16 weeks of modeling, fasting body weight and body mass index (BMI) were measured. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were measured in anterior venous blood, and atherosclerosis index (AI) was calculated. Meanwhile, intravenous glucose tolerance test was conducted to observe the changes of blood glucose and insulin, and the area under the curve (AUC) was calculated. After euthanasia, visceral fat rate was detected, and visceral fat tissue was taken for histopathological observation and fat cell diameter analysis. RT-PCR was used to observe the mRNA expression levels of Sirtuin1 (Sirt1), insulin-like growth factor-1 (IGF-1), glucose transporter 4 (GLUT4), peroxisome proliferator-activated receptor γ (PPARγ), peroxisome proliferator-activated receptor γ-assisted activator 1α (PGC-1α), forkhead box protein O1 (FoxO1), lipolysis-related gene hormone-sensitive lipase (HSL), and fat synthesis-related gene fatty acid synthase (FASN)changes in adipose tissue. Results: Compared with the NC group, the body weight, BMI, TC, LDL-C, HDL-C, AI and visceral fat rate were significantly increased after 16 weeks of high-fat/cholesterol induction in Tibetan mini-pigs(P＜0.05,P＜0.01). Meanwhile, the glucose tolerance curve was significantly delayed and the area under the curve of blood glucose and insulin was significantly increased (P＜0.05). HE pathological observation and quantitative analysis showed that fat cells were hypertrophy and the average cell diameter was increased significantly (P＜0.01). In addition, the mRNA expression levels of Sirt1,PGC-1α, GLUT4, and HSL were all decreased in varying degrees in adipose tissue, among which the mRNA expressions of Sirt1 and HSL were significantly decreased (P＜0.05), while the mRNA expressions of FOXO1, IGF-1, PPARγ, and FASN were significantly increased (P＜0.05, P＜0.01). Conclusion: Tibetan mini-pigs were induced by high fat/cholesterol diet to form obesity model with phenotypic characteristics such as lipid disorder and insulin resistance, whereas Sirt1 plays a key role in visceral fat deposition and insulin sensitivity reduction in obese Tibetan mini-pigs.