X射线全身照射后脾细胞内[Ca2+)]i对Con A反应性的变化

目的 研究电离辐射对ConA激活的脾细胞内游离钙离子Ca²⁺]i)动员的影响, 以探讨电离辐射免疫抑制作用的发生机理。方法 采用Fura2/AM双波长荧光测定法检测了X射线全身照射后的小鼠脾细胞内Ca²⁺]i对ConA反应性的变化。结果 小鼠接受0、0.5、1、2、4和6Gy吸收剂量的X射线全身照射后24小时, 脾细胞内Ca²⁺]i对ConA反应性呈剂量依赖性下降, 表现为Ca²⁺]i上升幅度减小、上升至峰值时间延长。2GyX射线全身照射后的时程观察表明, 照后2小时细胞内Ca²⁺]i对ConA反应性开始下降, 24小时达最低点, 照后5天才略有回升。结论 电离辐射所致免疫功能抑制与其抑制淋巴细胞内Ca²⁺]i动员等信息传递过程有关。

Effect of whole body irradiation with X rays on [Ca2+]i response to Con A in splenocytes

Objective To elucidate the possible mechanism of immunodepression following whole body irradiation (WBI) with X rays,intracellular free Ca ²⁺ (Ca²⁺]i) response to Con A in splenocytes of mice after WBI was studied. Method Fluorescent indicator fura-2 was used to assess the changes of Ca²⁺]i response to Con A in splenocytes of Kunming mice following WBI with X-rays. Results WBI with 0,0.5,1,2,4, and 6 Gy X-rays,respectively,could inhibit dose dependently mitogen Con A-stimulated Ca²⁺]i elevation and prolong the time of Con A-stimulated Ca²⁺]i elevation to a peak level in splenocytes of mice 24h after irradiation.Time course of 2 Gy WBI with X-rays indicated that inhibition of Con A-stimulated Ca ² ] i increase in splenocytes began at 2h,reached the lowest value at 24h,and slightly recovered at 5d after WBI. Conclusion Immunodepressive effect of ionizing radiation is associated with inhibition of Ca²⁺]i mobilization in T lymphocytes.