Therapy effect of cimetidine on spleen of mice irradiated with thoracic fractionated irradiation / 中华放射医学与防护杂志

ABSTRACT

Objective:To investigate the protective effect of cimetidine on mice with fractionated X-ray irradiation through right thorax.Methods:Thirty male C57BL/6 mice were randomly divided into control group, irradiation group and irradiation + cimetidine group (100 mg/kg), 10 mice in each group. Mice right thorax was locally irradiated with X-rays at a dose rate of 0.883 Gy/min to a cumulative dose of 24 Gy, 8 Gy per day in 3 d. After irradiation, the irradiation + cimetidine group was given cimetidine (100 mg·kg -1·d -1) for 7 d consecutively, and Ctrl and IR groups were given saline. Seven days after irradiation, the mice weight, spleen index and its T lymphocytes, B lymphocytes and NK cells were measured. Spleen tissue was stained with HE for pathological observation. Results:The fractionated irradiation lightly suppressed mice growth but obviously induced abscopal damage on spleen so that the spleen index were decreased. The irradiation group (0.369±0.011) had statistically significant difference compared with the control group(0.396±0.022)( t=2.978, P<0.05), the spleen pathological structure became disorder, and the percentages of CD3+ , CD4+ , CD3+ CD4+ , CD3+ CD8+ lymphocytes in spleen were decreased significantly( t=5.754, 3.570, 4.442, 5.281, 4.570, P<0.05). Cimetidine could partially restore the weight of irradiated mice, relieved spleen structure damage and effectively restored lymphocyte subsets, and partly recovered the levels of CD3+ , CD3+ CD4+ , CD3+ CD8+ lymphocytes in the spleen ( t=3.523, 2.706, 2.520, P<0.05). Conclusions:Cimetidine, as a potential radiation protection drug, could effectively reduce the mouse spleen injury induced by X-ray fractionated irradiation by improving mouse immune function.