Mitigation of 5-Fluorouracil-Induced Nephrotoxicity: The Protective Role of Thymoquinone and Hesperidin <i>in vitro</i> and <i>in vivo</i>

Anticancer medications often lead to organ toxicity, affecting patients’ quality of life. Phytochemical compounds like Thymoquinone (TQ) and Hesperidin (HESP) have shown promise in mitigating anticancer drug-induced toxicity. However, their ability to protect against nephrotoxicity produced by 5- Fluorouracil (5-FU) remains unexplored. To assess the protective efficacy of TQ, HESP, and their combination against nephrotoxicity induced by 5-FU in both <i>in vitro</i> and <i>in vivo</i> settings. Human Embryonic Kidney (HEK293) cells were subjected to various concentrations of 5-FU, TQ, and HESP, with cell viability assessed using the MTT assay. Apoptosis was evaluated through Acridine orange-Ethidium bromide dual staining (AO- EB). <i>In vivo</i> experiments utilized male Wistar albino rats, which received treatments of 5-FU alone, in combination with TQ, HESP, and both. Subsequent biochemical and histological analyses were conducted on serum and kidney tissue samples. <i>In vitro</i> studies revealed dose- dependent cytotoxicity of 5-FU, while TQ and HESP showed minimal toxicity. Combination treatment significantly improved cell viability compared to 5-FU alone. <i>In vivo</i> studies indicated that the administration of 5-FU resulted in elevated levels of serum creatinine and blood urea nitrogen (BUN), suggestive of kidney dysfunction, which were attenuated by TQ, HESP, or their combination. TQ and HESP also restored antioxidant enzyme activity and reduced inflammatory markers in kidney tissues. Histological analysis showed significant protection against 5-FU- induced renal damage with combination therapy. Our findings suggest that TQ and HESP, alone or in combination, possess protective effects against 5-FU-induced nephrotoxicity, possibly through antioxidant and anti-inflammatory mechanisms. These results highlight the potential of herbal medicines as adjunctive therapies to mitigate chemotherapy-induced organ toxicity and improve patient outcomes. Additional investigation is necessary to clarify the fundamental molecular mechanisms involved and to corroborate these findings in clinical contexts.