Methotrexate (MTX) is one of commonly used chemotherapeutic drugs, with well-known nephrotoxic 
effect. This study aimed to investigate the protective mechanisms of gossypin; a bioflavonoid present 
in plants, against MTX-induced nephrotoxicity. Rats were allocated into 4 groups: control, gossypin, 
MTX, and gossypin/MTX groups. Evaluation of renal function and histological images were done. 
Renal tissue oxidative markers of lipid peroxidation, total nitrite/nitrate (NO) level, reduced 
glutathione (GSH) and superoxide dismutase (SOD) were measured. Inflammatory and apoptotic 
markers as matrix metalloproteinase-9 (MMP-9) and beta-cell lymphoma-2 (Bcl-2) mRNA and 
protein expressions, respectively, as well as renal immunohistochemical expression of 
cyclooxygenase-II (COX-II) and fas ligand, were assessed. Renal P-glycoprotein (P-gp) expression 
was also measured. MTX caused a significant elevation in kidney functions, with noticeable elevation 
in‎ oxidative‎ stress‎markers'‎levels,‎as‎well‎ as‎COX-II and fas ligand expressions. Moreover, MTX 
decreased renal antioxidant enzymes, P-gp level, and Bcl-2 expression. Gossypin administration 
significantly improved renal functions and oxidative insults, in addition to significant improvement of 
inflammatory and apoptotic parameters. Gossypin administration before MTX also ameliorated renal 
damage, at least in part, via modulation of P-gp level. In conclusion, gossypin may be an effective 
nephroprotective adjuvant to MTX through antioxidant, anti-apoptotic, and anti-inflammatory 
mechanisms.