7-hydroxycoumarin-β-D-glucuronide protects against cisplatin-induced acute kidney injury via inhibiting p38 MAPK-mediated apoptosis in mice.

Aims: Cisplatin is a widely-used drug in the clinical treatment of tumors, but kidney nephrotoxicity is one of the reasons that limits its widespread use. We previously found that 7-hydroxycoumarin-β-D-glucuronide (7-HCG) was one of metabolites of skimmin and highly enriched in the kidneys and maintained a high blood concentration in skimmin-treated rats. Therefore, we investigated whether 7-HCG has a protective effect on cisplatin-induced acute kidney injury.

Materials And Methods: Male C57BL/6 mice were continuously administered 7-HCG for five days, and on the third day, an intraperitoneal injection of cisplatin was given to induce acute kidney injury. After 72 h, the mice were sacrificed for analysis. Serum and renal tissue were collected for renal function evaluation. RNA sequencing was used to explore mechanism, and further validated by western blot and immunohistochemistry. In addition, pharmacokinetic study of oral 7-HCG administration was performed to examine how much 7-hydroxycoumarin (7-HC) was metabolized and 7-HC possible effect on renal protection.

Key Findings: 7-HCG significantly reduced serum BUN and SCR levels, and alleviated pathological damage in renal tissue, and reduced the renal index. RNA sequencing revealed that 7-HCG could reverse p38 MAPK regulation and apoptosis. By western blotting, it was found that 7-HCG could reduce renal injury by reducing p-p38, p-ERK, p-JNK, cleaved-caspase3 and Bax. The immunohistochemical results of cleaved-caspase3 were consistent with western blotting. 7-HCG also significantly reduced the production of ROS in kidney tissue. Pharmacokinetic experiments have shown that 7-HCG in the blood increased rapidly and was eliminated slowly, with an average t of 18.3 h. And the concentration of 7-HCG in the target organ kidney was about 4 times higher than that in blood.

Significance: Our findings indicate that 7-HCG could exert its protective effect against cisplatin-induced acute kidney injury by inhibiting apoptosis via p38 MAPK regulation and elucidates its pharmacokinetics.