高温高湿环境对受照小鼠生存的影响

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

OBJECTIVE: To study the survival of the mice with gamma-ray irradiation in hot and humid environments (HHE) and determine the median lethal dose in 30 days (LD50/30). METHODS: One hundred mice were randomly divided into 2 groups (n=50 each) to receive gamma-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 LD50/30 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 LD50/30. 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 LD50/30 tended to also decrease in the HHE groups. CONCLUSION: The survival indexes of irradiated mice are significantly decreased in hot and humid environments.