Potential Hepatoprotective Effects of Adenosine Triphosphate Against Olaparib-Induced Oxidative Liver Injury: An Experimental Rat Model

Background: Olaparib, a clinically established poly (ADP-ribose) polymerase (PARP) inhibitor widely used in oncology, has significantly improved outcomes in several malignancies. However, increasing evidence indicates that olaparib may induce hepatocellular injury through mechanisms involving oxidative stress, inflammation, and mitochondrial dysfunction. Adenosine triphosphate (ATP), a key regulator of cellular bioenergetics and redox homeostasis, may confer protection against oxidative tissue injury. This study investigated the hepatoprotective effects of ATP against olaparib-induced oxidative liver damage in rats and compared its efficacy with melatonin. Methods: Twenty-four male albino Wistar rats were randomly assigned to four experimental groups (n = 6): healthy control (HG), olaparib-treated (OLP), ATP plus olaparib (ATOL), and melatonin plus olaparib (MLOL). Olaparib was administered at a dose of 100 mg/kg orally twice daily, whereas ATP (5 mg/kg, intraperitoneally) and melatonin (10 mg/kg, orally) were administered once daily. The treatments were administered for 14 consecutive days. Hepatic oxidative and inflammatory status was assessed by measuring malondialdehyde (MDA), total glutathione (tGSH), superoxide dismutase (SOD), catalase (CAT), interleukin-6 (IL-6) and ATP levels in liver tissue. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were measured as biochemical indicators of hepatocellular injury. Liver tissues were also examined histopathologically. Results: Olaparib administration significantly increased hepatic MDA and IL-6 levels together with serum ALT and AST activities, while significantly reducing hepatic tGSH and ATP levels and SOD and CAT activities compared with the healthy group (p < 0.001). Both ATP and melatonin significantly attenuated these alterations (p < 0.001). Notably, ATP demonstrated a more pronounced protective effect than melatonin, particularly in suppressing aminotransferase elevations and improving histopathological liver architecture. Conclusion: ATP significantly alleviates olaparib-induced hepatotoxicity by attenuating oxidative stress, suppressing inflammatory responses, restoring antioxidant defense mechanisms and significantly replenishing depleted hepatic ATP levels. These findings suggest that ATP may represent a promising therapeutic strategy for preventing PARP inhibitor-associated drug-induced liver injury. © 2026 Baykan et al.