[Expression level of cubilin in the rat model of diabetic nephropathy].

Objective: To observe the expression level of Cubilin in the renal tubules of rats with STZ-induced diabetic nephropathy, to assess its correlation with 24 hours' albuminuria, and to investigate the mechanisms of tubular dysfunction at the early stage of diabetic nephropathy.

Methods: Diabetic nephropathy was induced in Sprague-Dalwley rats by intraperitoneal injection of STZ, while the rats of normal group were injected with normal saline. Biochemical indices of blood and urine specimens were observed in both groups at weeks 2, 4 and 6 respectively. The renal expression levels of Cubilin in the two groups were determined by immunohistochemistry and RT-PCR.

Results: The expression level of Cubilin in the diabetic nephropathy group was significantly decreased at week 2 after operation (P < 0.05), and it continued to decrease from week 2 to week 6. Also there was significant difference between each two time-points (P < 0.05), and the Cubilin expression level was negatively correlated with albuminuria (P < 0.01).

Conclusion: The decreased expression level of Cubilin in early-stage diabetic nephropathy rats may partly contribute to the development of microalbuminuria. Cubilin can be regarded as one of the early markers when tubular dysfunction develops in the case of diabetic nephropathy.