Effect of phosphorylating-p38 mitogen-activated protein kinase on restructuration of extracellular matrix of diabetic glomeruli / 解放军医学杂志

ABSTRACT

Objective To study the expression and significance of the p38 mitogen-activated protein kinase (MAPK) and cAMP-responsive element binding protein (CREB 1) in experimental diabetic mellitus rats, and their relationship with extracllular matrix (ECM) restructuration. Methods Sixty male Wistar rats, with their kidneys removed surgically, were divided in two groups control group (n=30) and diabetic group (n=30). Diabetic model was reproduced by intraperitoneal injection of Streptozocin (STZ, 65mg/kg). Six rats of each group were sacrificed at 1, 2, 4, 8 and 12weeks after STZ injection. Immunohistochemistry was used to assess the expression of p-p38 MAPK and p-CREB 1 in both control and diabetic groups. Western blot was performed to determine the activity of p-p38 MAPK and p-CREB 1 in both groups. Semiquantitative competitive reverse transcription polymerase chain reaction (PCR) was performed to detect the expression of mRNA of p38 MAPK, CREB 1 and fibronectin (FN). Results Compared with the control group, expression of p-p38 MAPK in diabetic glomeruli was significantly enhanced at 1, 2, 4, and 8 weeks, then it lowered at 12 weeks. P-CREB 1 was increased at 2, 4, 8 weeks, also decreased at 12 weeks. Elevation of FN mRNA began after 4 weeks in diabetic rats. Conclusions Glomerular p38 MAPK activity was increased in early stage of diabetes. This activated p38 MAPK pathway in diabetic glomeruli may in part play a role in the pathogenesis of extracellular matrix restructuring.