免疫器官细胞凋亡在低水平铅暴露诱导小鼠免疫损伤中的作用

Apoptosis and harmful effects of low level lead exposure on immune system organs in mice

目的探讨免疫器官细胞凋亡在低水平铅暴露诱导小鼠免疫损伤中的作用。方法将120只健康成年雄性昆明小鼠,分为4组,自由饮水含醋酸铅125、250、500 mg/L蒸馏水12周,对照组给予同体积的蒸馏水。染毒结束后检测小鼠胸腺、脾脏器系数及巨噬细胞吞噬功能;石墨炉原子吸收法测定血清、胸腺和脾铅含量;流式细胞术检测胸腺、脾脏细胞凋亡率。结果小鼠染铅后,高剂量组胸腺、脾脏器系数升高(P<0.05);巨噬细胞吞噬功能中、高剂量组明显下降(P<0.05或<0.01),高剂量组吞噬指数显著性降低(P<0.05);各剂量组血清、胸腺、脾脏中铅含量显著增加(P<0.05);流式细胞结果表明,各剂量染铅组胸腺细胞凋亡率均显著增加(P<0.01),高剂量组染铅组脾脏细胞凋亡率显著增加(P<0.01)。结论长期低水平铅接触可以引起胸腺和脾脏细胞过度凋亡,导致淋巴细胞结构或功能出现障碍,最终引起细胞免疫和体液免疫功能障碍。

Objective To study the effects of apoptosis in immune organ induced by low levels acetate lead exposure on immune system damage in mice. Methods 120 male Kunming mice were randomly divided into 4 groups, and treated with 125, 250 or 500 mg/L acetate lead respectively in three treatment groups, and double-distilled water in control group through drinking water for 12 weeks. The organ index of immune organs and macrophage phagocytic capacity were detected 12 weeks later. Meanwhile, the lead contents in serum, thymus and spleen were detected by Atomic Absorption Spectrometer, and the apoptostic rates in thymus and spleen were detected by Flow cytometry. Results The thymus index and spleen index were significantly increased in 500 mg/L group（ P 〈 0.05）. The macrophage phagocytic rates in 250 mg/L and 500 mg/L groups were decreased compared with that in control group （ P 〈 0.05, P 〈 0.01 ）, respectively. The phagocytic index in 500 mg/L group was decreased significantly （ P 〈 0.05）. The apoptosis rates in thymus were increased in each treatment groups（ P 〈 0.01）, and that in spleen was increased in 500 mg/L group（ P 〈 0.01）. Conclusion Long-term, low-level lead exposure can result in apoptosis in thymus and spleen, leading to the structural and functional damage in lymphocytes and dysfunctional of immunity system eventually.