糖尿病大鼠PAI-1 mRNA的表达与心肌微血管改变的相关性研究

PAI-1 mRNA expression and myocardial mircovascular change in diabetic rats

目的通过研究老龄和青年糖尿病(DM)大鼠心肌微血管数目与心肌组织PAI-1 mRNA表达的改变,探讨高血糖和增龄对心肌微血管数目及心肌组织PAI-1 mRNA表达的影响。方法老龄和青年SD大鼠分别随机分为DM组和对照组,STZ液腹腔注射建立DM大鼠模型,喂养8周后,处死大鼠,取部分左心室组织进行免疫组化;剩余部分留做心肌组织PAI-1 mRNA检测。采用EnVision免疫组化法,CD34抗体检测心肌微血管内皮细胞特异性抗原CD34。利用医学图像分析软件计数心肌微血管数目。实时荧光定量PCR法检测各组心肌组织PAI-1 mRNA的表达。结果各年龄段大鼠,DM组心肌微血管数目显著低于同龄段对照组(P<0.01),DM组心肌组织PAI-1 mRNA的表达与同龄对照组相比则显著增多(P<0.01);老龄DM组心肌微血管数目明显低于青年DM组及青年对照组(P<0.01),老龄对照组心肌微血管数目与青年对照组无明显统计学差异(P>0.05),而老龄DM组心肌组织PAI-1 mRNA表达显著高于青年DM组及青年对照组(P<0.01);并且老龄对照组心肌PAI-1 mRNA的表达也高于青年对照组(P<0.05)。结论增龄对DM大鼠心肌微血管数目有影响,而对非DM大鼠无明显影响。增龄使大鼠心肌组织PAI-1 mRNA表达增强。各年龄段DM大鼠心肌微血管数目减少,心肌组织PAI-1 mRNA表达增强。

Objective To evaluate whether hyperglycemia and ageing influence myocardial microvessels and the expression of myocardial PAI-1 mRNA by observing changes in the number of myocardial microvessels and the expression of myocardial PAI-1 mRNA in aged and young diabetic rats. Methods Aged and young SD rats were randomized to diabetes mellitus （DM） group and control group. The DM model was established by intraperitoneal STZ injection. The rats were raised for 8 weeks and sacrificed. Part of the left ventrieular tissue was used for immunohistochemical evaluation, and the remaining part was used for detection of PAI-1 mRNA exprerssion. Myocardial microvascular endothelial specific antigen CD34 was detected by using CD34 antibody and EnVision immunohistochemistry. The number of myocardial microvessels was counted by Medical Image Analysis Software. The expression of myocardial PAI- 1 mRNA was detected by real-time fluorescence quantitative PCR. Results The number of myocardial microvessels of DM group was significantly smaller than that of the control in all age groups 8 weeks after modeling （P 〈 0.01）, and the number of myocardial microvessels of the aged DM group was significantly smaller than that of the young DM group and young control group （P 〈 0.01）, while there was no significant difference between the aged and young control groups （P 〉 0.05）. The expression of myocardial PAI- 1 mRNA in DM rats of all age groups was significantly increased as compared with the control group at corresponding ages （P 〈 0.01）. In addition, the expression of myocardial PAI-1 mRNA in the aged control rats was higher than that in the young control rats （P 〈 0.05）. Conclusion Ageing has a significant influence on the number of myocardial microvessels in diabetic rats but not in non-diabetic rats. Ageing enhances the expression of myocardial AI-1 mRNA in rats. The number of myocardial microvessels is decreased and the expression of myocardial PAI-1 mRNA is enhanced in diabetic rats at all ages.