低剂量电离辐射诱导小鼠睾丸生精细胞线粒体结构、ATPase活性及钙离子浓度的变化

Changes of mitochondrial structure,ATPase and Ca^(2+) concentration in spermatogenic cells of mouse testes induced by low dose radiation

目的:观察0.025~0.200 Gy X线低剂量电离辐射后3~24 h小鼠生精细胞线粒体结构、睾丸组织内ATPase和生精细胞钙离子浓度的变化,阐明线粒体结构与相关生物学功能改变在调控凋亡中的作用。方法:透射电镜检测小鼠睾丸生精细胞线粒体结构的改变;蛋白酶法检测ATPase活性的改变;以Fluo-3为探针,流式细胞术检测钙离子浓度([Ca2+]i)的变化。结果:0.075 Gy照射后12 h,小鼠精原细胞与精母细胞线粒体肿胀、空泡化、嵴断裂;精子细胞核固缩,顶体囊泡结构模糊,核膜结构不清楚,线粒体空泡化。0.025~0.200 Gy照射后12 h,睾丸组织中Na+-K+-ATPase活性较0 Gy照射降低,其中0.050~0.200 Gy较0 Gy显著降低(P<0.05),Ca2+-ATPase活性均较0 Gy照射显著降低(P<0.05);生精细胞中[Ca2+]i也具有同样的剂量-效应关系,其中0.075 Gy照射后,较0 Gy显著降低(P<0.05)。0.075 Gy照射后3~24 h,睾丸组织中Na+-K+-ATPase活性较0 h均显著降低(P<0.05);Ca2+-ATPase活性在3 h稍有升高后,6~24 h较0 h均显著降低(P<0.05);生精细胞中[Ca2+]i也具有相似的时程-效应关系。结论:低剂量电离辐射能够诱导小鼠睾丸生精细胞线粒体结构的改变;同时,其诱导ATPase活性和[Ca2+]i的变化具有剂量-效应与时程-效应规律性。

Objective To observe the ultrastructure,ATPase activity and Ca^2＋ concentration（i） of mitochondria in the sperematogenic cells of mouse testes 3-24 h after low dose radiation with 0.025-0.200 Gy X-rays,and illuminate the effects of mitochondrion structure and relative biological function on apoptosis.Methods The ultrastructure changes of mitochondria in the spermatogenic cells were observed with transmission electron microscope;the ATPase activity was measured with protein enzymic method;i was measured indirectly by flow cytometry with Fluo-3 probes.Results The mitochondria swelled and vacuolizated,and their cristae were broken in the spermatogonia and spermatocytes 12 h after irradiation,and their nuclei were karyopyknosis,the acrosomal vesicle structure was ambiguity,the membrane structure was unclear,and the mitochondria in spermatids were vacuolization.The activities of Na^＋-K^＋-ATPase in mouse testis tissue 12 h after irradiated with 0.025-0.200 Gy decreased compared with those with0 Gy,the Na＋-K＋-ATPase activities of the cells irradiated with 0.05-0.200 Gy decreased significantly compared with those with 0 Gy（P〈 0.05）,and Ca^2＋-ATPase of the cells irradiated with 0.025-0.200 Gy decreased significantly compared with those with 0 Gy（P〈 0.05）.The change of [Ca^2＋]i in mouse testis spermatogenic cells had similar dose-response relationship,[Ca^2＋]i after irradiated with 0.075 Gy decreased compared with those with 0 Gy（P〈 0.05）.After 0.075 Gy irradiation for 3-24 h,the activities of Na^＋-K^＋-ATPase in mouse testis tissues decreased obviously compared with those at 0 h（P〈 0.05）,the activities of Ca^2＋-ATPase in mouse testis tissues increased slightly at 3 h,then decreased at 6-24 h compared with those at 0 h（P〈 0.05）;i in mouse testis spermatogenic cells had similar time course-response relationship,i at 12 h decreased significantly compared with at 0 h（P〈 0.05）.Conclusion Low dose radiation could induce the structure changes in the spermatogenic cell mitochondria of mouse testes;at the same time,there are the regularities of dose-effect and time course-effect in the changes of ATPase activitiy and i induced by low dose radiation.