β-hydroxybutyrate Protects Against Cisplatin-Induced Renal Damage via Regulating Camkk2 Mediated Ferroptosis

Background: Cisplatin is a highly effective antineoplastic drug. However, the application of cisplatin is limited by cisplatin-induced nephrotoxicity. Recent researches have suggested that β-hydroxybutyrate (β-HB) works as a therapeutic agent protected against acute or chronic organ damage effectively. However, therapeutic mechanisms of β-HB on chemotherapy drugs inducing acute kidney injury remain elusive. Methods: Our research established a cisplatin-induced acute kidney injury (AKI) model, with β-HB or high fat diet administration. Blood urea nitrogen (BUN) and creatinine (Cr) in serum were tested, western blotting and immunohistochemical staining were used to evaluate ferroptosis and Camkk2. We further using HK-2 cells to clarify the effects of β-HB on ferroptosis and Camkk2 in vitro. Results: Simultaneously, cisplatin-induced abnormally elevation of BUN, Cr and renal tubular necrosis were significantly alleviated by exogenous or endogenous β-HB in vivo. In addition, β-HB also reduced ferroptosis biomarkers and increased anti-ferroptosis biomarkers in kidney. β-HB significantly attenuated cisplatin-induced cell ferroptosis and damage in vitro. Moreover, western blotting and immunohistochemical staining indicated that β-HB may prevent kidney injury through regulating the Camkk2. Conclusion: This study revealed protective effects of β-HB on cisplatin-induced nephrotoxicity, the newly potential molecular mechanisms underlying were inhibited ferroptosis and Camkk2.背景：顺铂（Cisplatin）是一种高效抗肿瘤药物，但其临床应用受限于顺铂诱导的肾毒性。近期研究表明，β-羟基丁酸（β-hydroxybutyrate, β-HB）可作为治疗剂，有效对抗急慢性器官损伤。然而，β-HB针对化疗药物诱导急性肾损伤的治疗机制仍不明确。方法：本研究构建了顺铂诱导的急性肾损伤（AKI, acute kidney injury）模型，并给予β-HB或高脂饮食干预。检测血清中血液尿素氮（BUN, blood urea nitrogen）与肌酐（Cr, creatinine）水平，采用蛋白质免疫印迹（western blotting）与免疫组织化学染色评估铁死亡（ferroptosis）与Camkk2的表达情况。进一步通过HK-2细胞开展体外实验，阐明β-HB对铁死亡与Camkk2的调控作用。结果：体内实验中，外源性与内源性β-HB可显著缓解顺铂诱导的血清BUN、Cr异常升高及肾小管坏死。此外，β-HB可降低肾脏内铁死亡相关生物标志物水平，并提升抗铁死亡生物标志物的表达。体外实验显示，β-HB可显著减轻顺铂诱导的细胞铁死亡与细胞损伤。进一步的蛋白质免疫印迹与免疫组织化学染色结果表明，β-HB或通过调控Camkk2发挥肾脏保护作用。结论：本研究揭示了β-HB对顺铂诱导肾毒性的保护作用，其潜在新型分子机制为抑制铁死亡与调控Camkk2。