Protective effects of cimetidine on micronucleated polychromatic erythrocytes in mice irradiated with 0.7Gy

Objective 　To study the radioprotective effect of cimetidine on single low-dose irradiated mice with radiosensitive detection indexes. Methods 　Forty-eight healthy male C57BL/6 mice were randomly divided into normal control group, model control group, positive group (200mg/kg WR2721) and cimetidine groups (7.5mg/kg, 15mg/kg and 30mg/kg). The mice were given intraperitoneal injection of cimetidine 2h before irradiation in cimetidine groups and WR2721 before irradiation once a day for two days in positive group. All the mice except those in normal control group were irradiated with 0.7Gy 60Co γ-ray at 5.83mGy/min rate. Peripheral blood cells, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content both in serum and liver, bone marrow DNA content and frequency of micronucleated polychromatic erythrocytes (fMPEs) were determined 24h after irradiation. Results 　Compared with normal control group, the peripheral white blood cells (WBCs) of irradiated mice decreased significantly (P<0.01), and fMPEs increased significantly (P<0.01) after irradiation. Except for 15mg/kg cimetidine group, the bone marrow DNA content was decreased significantly after irradiation (P<0.01, P<0.05). The SOD activity and MDA content in irradiated mice showed no significant difference compared with that of normal mice. Compared with model control group, peripheral WBCs and bone marrow DNA content showed no significant changes in treatment groups. The f MPE of 7.5mg/kg cimetidine group was 0.027‰, which was decreased significantly compared with that of model control group (P<0.01), and the dose reduction factor (DRF) of 7.5mg/kg cimetidine group was 3.338. Conclusion 　Cimetidine has good protective effect on micronucleated polychromatic erythrocytes (MPEs) in mice irradiated by 0.7Gy in single low-dose. DOI: 10.11855/j.issn.0577-7402.2015.12.03