Effect of human tissue kallikrein gene therapy on insulin resistance and nephropathy in type 2 diabetic rats / 中华内分泌代谢杂志

ABSTRACT

Objective To evaluate the therapeutic effect of recombinant adeno-associated viral vector (rAAV) expressing human tissue kallikrein gene (rAAV-HK) on insulin resistance and renal complications in tyDe2 diabetic rats. Methods Male Wistar rats were injected low dose streptozotocin and fed with high fat and sucrose diets to form type 2 diabetic model. rAAV mediated HK gene (HK group) or LacZ gene (LacZ group) were introduced to the diabetic rats, and their systolic blood pressure, fasting blood glucose and insulin, serum creatinine, urine creatinine, urine osmolarity and urine microalbumin were measured. The homeostasis model assessment of insulin resistance (HOMA-IR), urinary albumin excretion rate (UAER) and creatinine clearance rate (Ccr) were calculated. The expression of PI3-kinase p11o catalytic subunit (p110) and Akt phosphorylation on Thr-308 were detected by Western blot. The morphology of kidney wag observed. Results Delivery of rAAVHK resulted in a reduction in blood pressure at 2 weeks and the hypotensive effect lasted for the duration of the study. The HOMA-IR was significantly lower in HK group than LacZ group (4.76±0.33 vs 8.36±0.48, P<0.01) at the end of the study, fasting insulin level was reduced [(8.19±2.45 vs 13.85±3.76)mIU/L. P<0.01], but there was no significant change in fasting blood glucose [(13.09±3.01 vs 13.58±2.88)mmol/L].The phosphorylation of p11o and Akt Thr-308 were significantly decreased in skeletal muscle and liver in LacZ group and were almost corrected by HK gene therapy. The UAER and Ccr were significantly lower and urinary osmolarity were higher in HK-treated rats compared with LaeZ rats. Histological assessment indicated that the renal complication was relieved by HK gene delivery. Conclusion The rAAV-mediated HK gene delivery efficiently attenuated insulin resistance partly through PI3K/Akt pathway and diabetic nephropathy in type 2diabetic rats.