Influence of the Klotho/FGF23/Egr1 signaling pathway on calcium-phosphorus metabolism in diabetic nephropathy and the intervention of Shenyuan granules.

This study aimed to explore the effects of Shenyuan granules on the Klotho/FGFR23/Egr1 signaling pathway and calcium-phosphorus metabolism in diabetic mice models with impairment of renal function. Streptozotocin-induced diabetic nephropathy (DN) mice models were randomly divided into three groups: Shenyuan granules group (n=10), model control group (n=10), and blank control group (n=10). Corresponding drugs were given by gavage for 8 weeks. Blood glucose and serum creatinine (SCr), urea nitrogen (BUN), calcium (Ca), phosphorus (P) and mLAB were detected before and after administration. Moreover, RT-qPCR was performed to detect the expression of CYP24 and CYP27 mRNA in kidney tissue. Blood FGF23 was detected by ELISA. Western-blot and immunohistochemistry were performed to detect the expressions of Klotho, FGFR1, Egr1, CYP24, CYP27, ERK1/2 and p-ERK1/2. Compared with the blank control group, in the model control group serum FGF23,P, SCr and 24-hour proteinuria levels increased (P<0.05), serum Ca significantly decreased (P<0.05), expressionss of Egr1, CYP24, CYP27 and p-ERK1/2 were up-regulated (P<0.05), and the expressions of Klotho and FGFR1 were down-regulated (P<0.05). After treatment, compared with the model control group, in the Shenyuan granule group serum FGF23, P, SCr levels decreased (P<0.05), serum Ca increased (P<0.05), expressions of Egr-1, CYP24, CYP27 and p-ERK1/2 were down-regulated (P<0.05), and the expressions of Klotho and FGFR1 were up-regulated (P<0.05). Shenyuan granules may partly intervene in the expressions of CYP24 and CYP27 through the Klotho/FGF23/Egr1 signaling pathway, thereby improving calcium and phosphorus metabolism and alleviating renal injury in diabetic nephropathy.