Protective effects of cimetidine on rats with low-dose rate 60Co γ-ray cumulative irradiation / 解放军医学杂志

ABSTRACT

Objective To investigate the protective effects of cimetidine on rats with low dose rate (LDR) 60Co γ-ray cumulative irradiation. Methods Sixty male SD rats (6-8 weeks old) were randomized into 6 groups (10 each) normal control group, model group, positive control group (89.0 mg/kg lentinan), low-dose cimetidine group (23.3 mg/kg cimetidine), medium-dose cimetidine group (70.0 mg/kg cimetidine), and high-dose cimetidine group (210.0 mg/kg cimetidine). Except for rats in normal control group, the rest rats were irradiated with 60Coγ-ray to a cumulative dose of 0.5 Gy with a dose rate of 3.228 mGy/ h. Twenty-four hours after the last irradiation, peripheral blood cells, bone marrow DNA content, frequencies of micronucleated polychromatic erythrocytes (fMNPCE), bone marrow nucleated cells, sperm count, testis HE, sex hormones, superoxide dismutase (SOD), glutathione (GPx), catalase (CAT) activity, and malondialdehyde (MDA) content were measured. Results Compared with normal control group, in model group, WBC, lymphocyte and granulocyte content, bone marrow DNA content and the number of nucleated cells significantly decreased (P<0.05), but fMNPCE increased significantly (P<0.01). In addition, sperm count, testosterone (T), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels significantly reduced (P<0.05 or P<0.01), estradiol (E2) levels significantly increased (P<0.05), SOD, GPx and CAT activities significantly decreased (P<0.05 or P<0.01), and MDA levels significantly increased (P<0.01). Rat models were established successfully. Compared with model group, in positive control group, the bone marrow DNA content and T content significantly increased (P<0.05), antioxidant enzyme activity of SOD, GPx and CAT significantly increased (P<0.05 or P<0.01), while the contents of fMNPCE, MDA and E2 significantly reduced (P<0.05 or P<0.01). In the cimetidine-treated groups, the blood lymphocyte number and bone marrow DNA content significantly increased (P<0.01), the activity of antioxidant enzymes SOD, CAT, GPx, T, FSH and LH increased, and the content of fMNPCE, E2 and MDA decreased, the damage of testicular tissue structure decreased (P<0.05), and the number of sperm increased, but there has no statistic significance. Conclusion Cimetidine, as a potential radiation protection drugs, could effectively improve the rat injury with low-dose-rate 60Coγ-ray cumulative irradiation.