[Expression and implication of osteopontin in renal cortex of diabetic rats]

To investigate the expression and implication of osteopontin (OPN) in renal cortex of diabetic rats.

Experimental diabetes was reproduced in uninephrectomized rats by giving streptozotocin (STZ). The animals were divided into two groups: control group and diabetic group (each n=24). Immunohistochemistry and Western blotting were used to detect the protein expression of OPN, CD68, and proliferating cell nuclear antigen (PCNA). At the same time the mRNA expression of OPN was detected by in situ hybridization.

Compared with control group, blood glucose, blood urea nitrogen (BUN), 24-hour urine protein quantum and quantification of OPN protein significantly increased while creatinine clearance rate (CCr) was significantly decreased in diabetic rat group 1, 2, 4 and 8 weeks after STZ injection. The protein of PCNA were also higher than that of control group 1 and 2 weeks after STZ injection (all P<0.05), and the increase in CD68 was observed at week 4 and week 8.

Overexpression of OPN may be responsible for the proliferation of tubular cells at early stage of diabetic nephropathy and for the accumulation of macrophage at later stage.