Protective Effects of Medicago sativa Extract on Oxidative Stress and Apoptosis in a DMBA-Induced Experimental Breast Carcinogenesis Model

Background Breast cancer is a leading cause of cancer-related morbidity and mortality worldwide, and oxidative stress plays a critical role in early mammary carcinogenesis. Medicago sativa has been reported to possess antioxidant properties; however, its effects on early oxidative stress–apoptosis interplay in breast tissue remain unclear. Methods Twenty-eight female Wistar albino rats were randomly allocated into four groups: control, DMBA, Medicago sativa , and DMBA + Medicago sativa (n = 7 each). Breast carcinogenesis was initiated by a single intraperitoneal dose of 7,12-dimethylbenzaanthracene (DMBA; 80 mg/kg). Medicago sativa extract was administered orally at 250 mg/kg/day for 10 weeks. Serum malondialdehyde (MDA), total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were measured. Mammary tissues were evaluated histopathologically and immunohistochemically for Bax and Bcl-2 expression. Results DMBA administration significantly increased serum MDA, TOS, and OSI levels compared with the control group (p < 0.05). Medicago sativa treatment significantly reduced MDA, TOS, and OSI levels in the DMBA + Medicago sativa group (p < 0.05). No statistically significant difference in TAS levels was observed between the DMBA and DMBA + Medicago sativa groups. Histopathological analyses revealed moderate fibrosis, inflammatory infiltration, degenerative epithelial changes, and ductal hyperplasia in the DMBA group, whereas these alterations were attenuated following Medicago sativa treatment. The immunohistochemical evaluation demonstrated that, compared with the DMBA group, Bax expression with pro-apoptotic function increased, while Bcl-2 expression with anti-apoptotic function decreased in the DMBA + Medicago sativa group. Conclusions Medicago sativa mitigates DMBA-induced early mammary tissue damage by reducing oxidative stress and modulating Bax/Bcl-2–mediated apoptotic signaling prior to overt tumor formation, highlighting its mechanistic relevance in targeting early stages of breast carcinogenesis.