基质金属蛋白酶9在大鼠糖尿病肾病发病中的作用

目的 探讨糖尿病肾病大鼠肾局部金属蛋白酶9(MMP-9)在糖尿病肾病发生发展的作用.方法 健康雌性清洁级大鼠,随机分成糖尿病组和正常对照组,采用腹腔注射链脲佐菌素制备糖尿病大鼠模型.分别于4、8周处死,应用免疫组化及酶谱分析方法(zymography)观察各组肾组织MMP9的蛋白表达及其活性水平,分析MMP-9与细胞外基质Ⅳ型胶原、层粘连蛋白(LN)的相关性.结果 MMP-9在正常对照组肾小球、肾小管细胞均有阳性表达(4周,26.63%+2.94%;8周,29.86%±0.89%);而糖尿病组随病程延长表达明显减弱(4W,16.11%±2.86%;8周,13.14%±2.68%),MMP-9活性也明显降低(正常组4周110.47±7.12;8周,111.50±6.95;糖尿病组4周82.74±10.92;8周,80.05±12.83),两组间各项指标的差异有统计学意义(均P＜0.01).MMP-9活性与Ⅳ型胶原(r=-0.852,-0.795,P＜0.01)、LN(r=-0.897,-0.832,P＜0.01)呈显著负相关.结论 糖尿病肾病时肾组织中MMP-9表达水平降低,糖尿病肾病的发病机制可能与MMP-9水平降低有关.

Role of matrix metalloproteinase 9 in the pathogenesis of diabetic nephropathy in rats

Objective To explore the role of matrix metalloproteinase 9(MMP-9) in the development of diabetic nephropathy(DN).Methods Healthy female rats were randomly divided into diabetic group and control group. Diabetic rat model was established by injection of STZ. Four and eight weeks after rats were sacrificed, zymography was used to detected the activity of renal MMP-9. Immunohistochemistry was used to examine the expressions of renal MMP-9, type Ⅳ collagen and laminin. Correlation of MMP-9 expression and activity with type Ⅳ collagen and laminin was performed. Results MMP-9 expression was positive in glomerular and tubular cells of control group (week 4:26.63%±2.91%, week 8:29.86%±0.89%) , while above MMP-9 expression was down-regulated significantly in diabetic group (week 4:16.11%±2.86% , week 8:13.14%.±2.68%).The activity of MMP-9 decreased significantly in diabetic group compared to control group as well(control group week 4:110.47±7.12, week 8:111.50±6.95; diabetic group week 4:82.74±10.92, week 8:80.05±12.83)(all P＜0.0l). The expression and activity of MMP-9 were negatively correlated with type Ⅳ collagen (r=-0.852, -0.795, all P＜0.01) and laminin expression (r=-0.897, -0.832, all P＜0.01). Conclusion MMP-9 expression and activity decrease in renal tissues of diabetic rats, which may play an important role in the pathogenesis of diabetic nephropathy.