Efficacy of tamoxifen and thymoquinone on tumor development, lipid peroxidation, and total antioxidant capacity in DMBA induced mammary carcinoma in female Sprague-Dawley rats

Tamoxifen (TAM) is a drug used for treatment and prevention of breast cancer. However, TAM has been reported to induce liver tumors in several animal models due to overproduction of free radicals and lipid peroxidation. Thymoquinone (TQ), from Nigella sativa seeds, is a Middle East natural medicine and it has been used to treat a number of diseases, including cancer. The aim of my study was to investigate the effect of TQ and TAM on tumor development, lipid peroxidation level, and total antioxidant capacity in DMBA treated female Sprague-Dawley rats. Five groups of 10 rats (control, DMBA, TAM, TQ, and TAM+TQ) were used. Mammary tumors were induced by DMBA which was given by oral gavage to four groups: DMBA, DMBA+ TAM, DMBA+ TQ, and DMBA+ TAM & TQ. The control group received tap water only. Starting three weeks later, TAM and/or TQ were administered daily for 10 weeks. Mammary tumors were found in two DMBA treated animals. There was coloration in the mammary glands in four other DMBA treated animals. No mammary tumors or mammary gland coloration was observed in other groups. Rats treated with TAM showed a significantly higher level of lipid peroxidation when compared to control (