Ionizing radiation is a widely used therapy for solid tumors. However, high-dose ionizing radiation causes apoptosis, transforms normal cells into tumor cells, and impairs immune functions, leading to the defects in the removal of damaged or tumor cells. In contrast, low-dose radiation has been reported to exert various beneficial effects in cells. This experimental study investigated the effect of γ rays at low dose on the development of colorectal tumor in a 1,2-dimethylhydrazine (DMH)-induced colon cancer. Colorectal tumor model was induced in Wistar rats by subcutaneous injection of DMH (20 mg/kg) once a week for 15 weeks. Starting from zero day of DMH injection, a single low dose of whole-body γ irradiation of 0.5 Gy/week was applied to the rats. A significant reduction in lipid peroxidation, nitric oxide, and elevation in the glutathione content and antioxidant enzyme activity (superoxide dismutase and catalase) were observed after γ irradiation comparing with DMH group. Moreover, γ ray reduced the expressions of multidrug resistance 1 (MDR1), β-catenin, and cytokeratin 20 (CK20) those increased in DMH-treated rats. However, survivin did not change with γ ray treatment. A histopathological examination of the DMH-injected rats revealed ulcerative colitis, dysplasia, anaplasia, and hyperchromasia. An improvement in the histopathological picture was seen in the colon of rats exposed to γ rays. In conclusion, the present results showed that low-dose γ ray significantly inhibited DMH-induced colon carcinogenesis in rats by modulating CK20, MDR1, and β-catenin expression but not survivin expression.

Cyclophosphamide (CP) is a widely used anticancer and immunosuppressant that induces oxidative stress. To ameliorate the side effects resulted from CP treatment, liposomes were tested as an efficient drug delivery system with or without vitamin C as an antioxidant. CP resulted in clastogenic and cytotoxic effects that significantly increased for the total chromosomal aberrations as well as the numerical ones in the CP group (150.8 and 6, respectively) than the control group (6.6 and 0.0) as mean values at p < 0.05. Micronucleus assay showed a significant increased micronucleated polychromatic erythrocytes percentage (MNPCEs% = 11.7%) and a significant decrease of polychromatic to normochromatic erythrocytes ratio (0.551) when compared to the group treated with liposomised CP and vitamin C (3.44%; 0.795, respectively) at p < 0.05. Also, the total glutathione S-transferase activity as a body antioxidant enzyme was decreased from 52.2 in the control to 16.09 nmol/min/mg protein in CP group at p < 0.05, while the highly significant amelioration results were observed in the liposomised vitamin C and CP group (40.88 nmol/min/mg protein). Our findings support the potential use of CP in a liposomal formulation doped with vitamin C to diminish the potential side effects of the agent.