Objective: To observe the expressions of bone matrix proteins and monocyte chemoattractant protein-1 ((MCP-1) in the renal arteriole of diabetic nephropathy (DN) rats and analyze their correlations and roles in diabetic nephropathy.
Methods: Adult Sprague-Dawley male rats were used to establish the animal model of diabetic nephropathy induced by peritoneal injection of 55 mg/kg of streptozocin. Calcium deposit around the renal arteriole was observed by alizarin red staining. The protein and mRNA levels of core-bind factor alpha 1 (cbfalpha1), bone morphogenetic protein 2 (BMP-2) and matrix Gla protein (MGP) in renal arteriole of DN rats were detected by immunohistochemistry, in-situ hybridization and real-time PCR. The biochemical indices were detected by routine test.
Results: 1. Blood glucose and Urine protein of 24 h were significantly increased in the renal arteriole of DN rats versus the control rats (P < 0.05), serum creatinine (SCr) and phosphorus were significantly increased from 12 weeks. 2. Little deposit of calcium salt was observed in the renal arteriole of DN rats at the 4th week and a large amount of deposit was observed at 24th week, but no calcium deposit was observed in control rats. 3. Cbfalpha1 and BMP-2 expressions were significantly increased in the renal arteriole of DN rats from 4 to 24 weeks vs. the control rats. MGP mRNA expression in the renal arteriole of DN rats was significantly decreased from 4 to 24 weeks. MCP-1 expression was obviously upregulated in the renal arteriole of DN rats at 24th week versus that at 4th and 12th week. No MCP-1 expression was observed in the renal arterioles of control rats. MCP-1 were positively correlated with the expression of cbfalpha1 and BMP-2.
Conclusion: Bone matrix proteins has already expressed in renal arteriole before the formation of vascular calcification. MCP-1 can affect the expression of cbfalpha1, BMP-2; cbfalpha1, BMP-2, MGP and MCP-1 may be involved in the formation of vascular lesions of DN.