Abnormal expression of angiopoietins in glomerulus following podocyte injury and its role in the development of progressive glomerulosclerosis in rats

AIM: To study the potential pathological role of abnormal expression of endogenous angiopoietins in progressive glomerulosclerosis. METHODS: 80 male Wistar rats were randomly allocated into sham operation group (sham, n=25), unilateral nephrectomy group (UNx, n=25) and UNx＋daunorubicin (DRB)group (n=30). The rats in DRB group were intravenously injected with DRB (5 mg/kg) on the seventh and the fourteenth day respectively after excising one kidney. Then, at week 1, 2, 4, 6 and 8, 5, male Wistar rats from each group were taken randomly for determining 24 h urinary protein quantitative measurement (24hUPQ), BUN, Scr, and the kidneys were examined by electronic microscope, PAS staining, immunohistochemical staining and in situ hybridization histochemistry. RESULTS: There was a trend towards an increase respectively in levels of 24hUPQ, Bun, Scr, GSI in DRB from week 2 to week 8. Electronic microscope revealed that podocyte injury presented in DRB group. Expression of Ang1 mRNA and protein in glomerulus in DRB group decreased, while expression of Ang2 protein in glomeruli in DRB group increased. In DRB group, expression of Ang1 protein had a negative correlation with 24hUPQ, BUN, Scr, GSI, expression of Ang2 protein and CoIV protein. Expression of Ang2 protein had a positive correlation with 24hUPQ, BUN, Scr, GSI,expression of CoIV protein. CONCLUSION: Podocyte injury may lead to glomeruli abnormally express angiopoietins. A decrease in expression of Ang1, and upregulation in expression of Ang2 may facilitate progressive glomerulosclerosis in the rat.