神经肽Y Y5受体反义寡核苷酸对肥胖大鼠血清胰岛素与C肽水平及脂肪组织TNFα基因mRNA表达的影响

Effects of intracerebroventricular injection of antisense oligodeoxynucleotide to neuropeptide Y Y5 receptor on levels of serum insulin, C peptide and TNFα gene mRNA expression in adipose tissue in diet-induced obese rats

目的 探讨神经肽YY5 (NPYY5 )受体反义基因治疗对肥胖大鼠血清胰岛素与C肽水平及脂肪组织TNFα基因表达的影响 ,评价该疗法对肥胖大鼠高胰岛素血症的影响。方法 建立高营养饮食诱导的肥胖大鼠模型 ,侧脑室插管后注射NPYY5受体反义、错义寡核苷酸及生理盐水 ,称大鼠腹膜后脂肪组织湿重 ,采用放免法测定血清胰岛素与C肽水平 ,RT PCR技术检测脂肪组织中TNFα基因的表达水平。结果 (1)肥胖对照组大鼠的血清胰岛素与C肽水平、腹膜后脂肪组织湿重及脂肪组织TNFα基因mRNA表达水平均显著高于正常对照大鼠。NPYY5受体反义寡核苷酸干预后 ,肥胖大鼠上述观察指标水平均明显低于肥胖对照组、肥胖盐水组、肥胖错义组 ,除腹膜后脂肪组织湿重与肥胖错义组差异无显著意义 ,其余指标与肥胖对照组、肥胖盐水组、肥胖错义组相比差异均有显著意义 ,肥胖反义组各指标水平均近于正常对照组。而肥胖对照组、肥胖盐水组、肥胖错义组之间 ,除肥胖错义组脂肪组织湿重低于肥胖对照组外 ,其余各观察指标差异均无显著意义。肥胖盐水组、肥胖错义组各指标水平均明显高于正常对照组 ,除腹膜后脂肪组织湿重与正常对照组相比差异无显著意义 ,其余指标差异均有显著意义 ;(2 )肥胖大鼠脂肪组织TNFα基因mRNA表达水平与血清胰岛素水平、

Objective To investigate the effects of intracerebroventricular injection of antisense oligodeoxynucleotide to neuropeptide Y Y5 receptor on the levels of serum insulin, serum C peptide and TNFα gene mRNA expression in adipose tissue in high-nutritive diet-induced obese rats and to evaluate the effect of this therapy on hyperinsulinemia in obese rats. Methods The diet-induced obese rat models were established by feeding a high-nutritive diet for 7 weeks. Lateral ventricular cannulization was performed in obese rats which then received an intracerebroventricular injection of either 10 μl / rat (5 μg / μl ) neuropeptide Y Y5 receptor antisense or mismatched oligodeoxynucleotide or 10 μl saline three times per day for 2 days. After the rats were killed, the wet weights of retroperitoneal adipose tissue were measured and the levels of serum insulin and C peptide were detected by using radioimmunoassay. Total RNA from the retroperitoneal adipose tissue was extracted and the level of TNFα gene mRNA expression was evaluated by RT-PCR.Results (1) The wet weights of retroperitoneal adipose tissue, the levels of serum insulin and C peptide, the levels of TNFα gene mRNA expression in adipose tissue were significantly higher in diet-induced obese rats than those in normal rats. After the obese rats were treated with NPY Y5 receptor antisense oligodeoxynucleotide, the levels of all the above indexes in the antisense group were markedly lower than those in the control group, the saline group, and the mismatched group. There were significant differences in the levels of the indexes between the antisense group and the control group, the saline group, the mismatched group, except for the difference in the wet weights of retroperitoneal adipose tissue between the antisense group and the mismatched group. The levels of the indexes in the antisense group were close to those in the normal non-obese rats. Meanwhile, there was no significant difference in all the indexes among the control group, the saline group and the mismatched group, except that the wet weight of retroperitoneal adipose tissue in the mismatched group was lower when compared with that in the control group (P<0.05). The levels of the indexes in the saline group and the mismatched group were also markedly higher than those in the normal non-obese rats. The difference in the levels of the indexes except for the wet weight of retroperitoneal adipose tissue between the saline group, the mismatched group and the normal non-obese rats reached the level of significance. (2) There were significant positive correlations between the levels of TNFα gene mRNA expression and the levels of serum insulin (r=0.3724,P<0.05), the levels of serum C peptide (r=0.416 8,P<0.01). Conclusion Intracerebroventricular injection of antisense oligodeoxynucleotide to neuropeptide Y Y5 receptor may improve hyperinsulinemia in diet-induced obese rats by reducing the levels of both serum insulin and serum C peptide, the wet weights of retroperitoneal adipose tissue and may down-regulate the expression level of TNFα gene in adipose tissue.