褪黑素对电离辐射诱导离体小鼠淋巴细胞凋亡的影响

目的：探讨褪黑素（melatonin，MLT）对电离辐射诱导的离体小鼠淋巴细胞凋亡的影响及其机制。 方法：采用流式细胞术（FCM）和荧光分光光度法分别检测小鼠胸腺和脾淋巴细胞凋亡小体百分率和DNA裂解率。 结果：电离辐射可诱导离体小鼠胸腺、脾淋巴细胞凋亡，在0.5~6.0 Gy范围内凋亡呈剂量依赖性增加。照射前预先加入2 mmol?L^-1MLT，细胞凋亡小体百分率和DNA裂解率与单纯照射组比较均显著降低，胸腺、脾淋巴细胞凋亡小体百分率分别降低为单纯照射组的86.25%和89.22%，DNA裂解率分别降低为单纯照射组的87.23%和89.16%。 结论：MLT在体外可减轻电离辐射诱导的小鼠淋巴细胞凋亡，对淋巴细胞损伤有防护作用。

Effects of melatonin on apoptosis of mouse lymphocytes induced by ionizing radiation in vitro

Objective To explore the effects of melatonin (MLT) on the apoptosis of mouse lymphocytes in vitro induced by ionizing radiation and its mechanism. Methods The percentages of apoptotic bodies and the DNA lytic rates in mouse thymocytes and splenocytes were detected with flow cytometry and fluorospectrophotometry, respectively. Results The apoptosis of mouse thymocytes and splenocytes increased in a dose-dependent manner in 0.5~6.0 Gy X-irradiation. When MLT of 2 mmol·L -1 was added into thymocytes or splenocytes in vitro before irradiation with 0.5~6.0 Gy X-rays, the percentages of apoptotic bodies and the DNA lytic rates all decreased significantly compared with those in the irradiation group. The percentages of apoptotic bodies in these two kinds of cells were 86.25% and 89.22% of those in the irradiation group, respectively, and the DNA lytic rates were 87.23% and 89.16%, respectively. Conclusion MLT can decrease the apoptosis of mouse lymphocytes and has the protective effects on the damage of lymphocytes.