Ⅰ型、Ⅲ胶原mRNA在Ⅱ型糖尿病大鼠窦房结的表达及变化

摘要

目的:探讨Ⅱ型糖尿病大鼠窦房结(SAN)内Ⅰ、Ⅲ型间质胶原重塑及胰岛素对其的影响.方法:高糖高脂饮食加小剂量链脲佐菌素(STZ)腹腔注射制备Ⅱ型糖尿病大鼠模型,并随机分为正常对照组、糖尿病组和胰岛素治疗组(每只3 U/d股内侧皮下注射),对照组和糖尿病组注射等剂量的生理盐水(股内侧皮下注射)每天1次,持续喂养4个月;以半定量RT-PCR检测Ⅰ型、Ⅲ胶原mRNA在各组窦房结的表达及变化.结果:与对照组比较,糖尿病组Ⅰ、Ⅲ型胶原纤维在窦房结内明显增加;治疗组较糖尿病组呈显著下降.图像分析结果显示Ⅰ、Ⅲ型胶原mRNA表达量为糖尿病组﹥治疗组﹥对照组.糖尿病组Ⅰ/Ⅲ型胶原基因mRNA表达比值明显较对照组上升.结论:Ⅱ型糖尿病可致窦房结胶原重塑,胰岛素治疗可使其发生逆转.%Objective:To investigate the reconstruction of type Ⅰand Ⅲ interstitial collagen of sinuatrial node and the role of insulin in type Ⅱ diabetic rats.Methods:The experimental type Ⅱ diabetic rats were induced by peritoneal injection of streptozotocin (STZ,30 mg/kg)and fed with high fat and high glucose food.Rats were divided into three groups,normal control group (NC group),diabetes group and treatment group.The treatment group was injected with 3 U/d insulin hypodermically at the interfemus for 4 months,and the expression of collagen typeⅠandⅢmRNA was detected in each group. Results:Collagen typeⅠand Ⅲ in diabetes group were increased greatly but they were decreased in treatment group.The expression of collagen typeⅠand Ⅲ in diabetes group,treatment group and NC group were decreased gradually.The ratio of collage typeⅠand Ⅲ increased greatly.Conclusion:The interstitial collagen is reduced after the diabetic rats are treated by insulin which could reverse the disorder of collagen types.