AAV9介导的CTRP9过表达对糖尿病大鼠心肌纤维化的抑制作用

Effects of overexpression of CTRP9 mediated by AAV9 on myocardial fibrosis in diabetic rats

目的:探讨AAV9介导的CTRP9过表达对糖尿病大鼠心肌纤维化的作用及其机制。方法:45只6周龄健康SD大鼠分为对照组、GFP组和CTRP9组,每组15只。GFP组和CTRP9组腹腔注射链脲佐菌素(STZ)造模,对照组腹腔注射生理盐水;2周后,GFP组和CTRP9组分别经尾静脉缓慢注射携带GFP和CTRP9基因的AAV9,对照组同法给予生理盐水。转染12周后检测血糖及血清CTRP9水平,进行心肌Masson染色并计算胶原容积分数(CVF)以评价大鼠心肌纤维化程度,应用RT-PCR和Western blot分别检测3组大鼠心肌TGF-β1/Smads通路中各因子mRNA和蛋白水平。结果:转染12周后,与GFP组相比,CTRP9组大鼠血清CTRP9上升,血糖降低,CVF也降低(P<0.05);同时TGF-β1、Smad2和Smad3 mRNA表达水平降低,Smad7 mRNA表达水平升高(P<0.05),α-SMA、TGF-β1和p-Smad2/3蛋白表达水平降低,Smad7蛋白表达升高(P<0.05)。结论:AAV9介导的CTRP9过表达可能通过调节TGF-β1/Smads信号通路来抑制糖尿病大鼠的心肌纤维化。

Aim： To investigate the effects of CTRP9 on myocardial fibrosis and the mechanism in diabetic rats.Methods： A total of 45 healthy SD rats were assigned into 3 groups： control group,GFP group and CTRP9 group,15 rats in each group. Streptozotocin at 60 mg/kg was intraperitoneally injected in rats of GFP group and CTRP9 group to make diabetic rat model,and normal saline was injected in control group. After 2 weeks,the GFP group and the CTRP9 group were infected with adeno-associated virus 9（ AAV9） carrying GFP and CTRP9 gene through tail vein,respectively. Meanwhilecontrol group was injected with normal saline. After 12 weeks,the blood glucose and serum CTRP9 were measured. Masson staining was used to assess myocardial fibrosis and to calculate the cardiac collagen volume fraction（ CVF）. RT-PCR and Western blot were amplied to detect the mRNA and protein levels of TGF-β1/Smads pathway-related factors in myocardial tissue of rats. Results： After 12 weeks,compared with GFP group,the level of CTRP9 increased and that of blood glucose as well as CVF decreased significantly in CTRP9 group（ P〈0. 05）,meanwhile,the mRNA expressions of TGF-β1,Smad2 and Smad3 and the protein levels of α-SMA,TGF-β1 and p-Smad2/3 were decreased significantly（ P〈0. 05）,and the mRNA and protein expressions of Smad7 were increased significantly（ P〈0. 05）. Conclusion： Overexpression of CTRP9 inhibits myocardial fibrosis by regulating the expression of TGF-β1/Smads signaling pathway in diabetic rats.