Effect of warming kidney and spleen recipe on the expressions of nephrin and podocin in glomerular podocyte of diabetic nephropathy rats

Objective To observe the effect of warming kidney and spleen recipe on the expressions of nephrin and podocin in glomerular podocyte of diabetic nephropathy rats. Methods Thirty diabetic nephropathy rats induced by streptozotocin were randomly divided into 5 groups, which were the model control group (10 mL·kg-1·d-1 isotonic sodium chloride solution), positive control group (25 mL·kg-1·d-1 valsartan), low dose group (7.5 g·kg-1·d-1 warming kidney and spleen recipe), medium dose group (15 g·kg-1·d-1 warming kidney and spleen recipe) and high dose group (30 g·kg-1·d-1 warming kidney and spleen recipe) with 6 rats in each group, and 6 normal rats were served as the normal control group (10 mL·kg-1·d-1 isotonic sodium chloride solution). Then the nephrin and podocin proteins and mRNA expressions in glomerular podocytes of rats in each group were detected by immunohistochemistry and fluorescence quantitative PCR respectively, after all rats were given intragastric administration for 8 weeks. Results Immunohistochemistry results showed that the expressions of nephrin and podocin proteins in podocytes of rats in six groups were statistically different (F = 6.656, 8.667; P = 0.016, 0.007). The expressions of nephrin and podocin proteins in podocytes of rats in the model control group were lower than those in the normal control group (all P < 0.05). Compared with the model control group, the nephrin and podocin expressions in medium and high dose groups increased (all P < 0.05), while the podocin protein expression in the low dose group was higher than that in the model control group (P < 0.05). In addition, podocin proteins expressions in the low, medium and high dose groups were higher as compared with the positive control group (all P < 0.05). The results of quantitative PCR showed that the relative expressions of nephrin and podocin mRNA in podocytes of rats in six groups were statistically different (F = 5.412, 3.308, P = 0.034, 0.015). Compared with the normal control group, the relative expressions of nephrin and podocin mRNA in podocytes in the model control group were significantly lower (all P < 0.05). Furthermore, the relative expressions of nephrin and podocin mRNA in medium and high dose groups and the positive control group significantly increased than those in the model control group (all P < 0.05), while the relative expression of podocin mRNA only increased in the low dose group (P < 0.05). At the same time, the relative expression of nephrin mRNA only decreased in the low dose group as compared with the positive control group (P < 0.05). Conclusion Warming kidney and spleen recipe could provide a protective effect for nephrin and podocin in glomerular podocyte, which suggested that it might maintain the normal glomerular filtration function and reduce the urinary protein excretion rate in order to prevent and treat diabetic nephropathy. Key words: Warming kidney and spleen recipe; Diabetic nephropathy; Nephrin; Podocin