高温高湿环境对受照小鼠生存的影响

Survival of mice with γ-ray irradiation in hot and humid environments

目的研究高温高湿环境下,对经一定剂量γ射线照射小鼠生存的影响及30 d内引起小鼠50%死亡的辐射剂量(LD50/30)的变化规律。方法将实验动物分为室温组和高温高湿环境下30、60、90和120 min共5组,各组分别给予7、9 Gy的γ射线照射和相应的高温高湿作用时间后,观察30 d内小鼠的死亡情况。同时对室温组、高温高湿60、90 min组,分别给予5、7、9 Gy的γ射线照射,观察30 d内的死亡情况,计算出各组小鼠的LD50/30。结果高温高湿组小鼠与室温组小鼠相比,感染加重、平均存活时间缩短、中位生存时间显著提前(P<0.05);LD50/30存在下降趋势。结论高温高湿环境下,受照小鼠的生存指标明显下降。

Objective To study the survival of the mice with γ-ray irradiation in hot and humid environments (HHE) and determine the median lethal dose in 30 days (LD 50/30 ). Methods One hundred mice were randomly divided into 2 groups (n=50 each) to receive γ-ray irradiation at the dosage of either 7 or 9 Gy, and were then immediately transferred to the chambers simulating HHE for treatment for 30, 60, 90 or 120 min respectively, leaving one group at room temperature (n=10 in each group). The death rates of the mice within 30 days were observed. For LD 50/30 determination, another 180 mice in 3 equal groups were subjected to irradiation at 5, 7 or 9 Gy, respectively and after further division of each group into 3 equal subgroups , the mice underwent treatment in HHE for 60 or 90 min respectively or at room temperature to observe their death rates within 30 days and calculate the LD 50/30 . Results Compared to the mice treated at room temperature, earlier onset and more cases of infections with much severity were observed in all the HHE groups, with reduced average survival time and obviously shortened median survival time (P<0.05), and LD 50/30 tended to also decrease in the HHE groups. Conclusion The survival indexes of irradiated mice are significantly decreased in hot and humid environments.