Abstract:

Abstract:Objective To observe the ultrastructure,ATPase activity and Ca²⁺concentration (［Ca²⁺］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;［Ca²⁺］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 with 0 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 Ca²⁺-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 ［Ca²⁺］i in mouse testis spermatogenic cells had similar dose-response relationship,［Ca²⁺］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 Ca²⁺-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);［Ca²⁺］i in mouse testis spermatogenic cells had similar time course-response relationship,［Ca²⁺］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 ［Ca²⁺］i induced by low dose radiation.

Key words: ultrastructure;ATPase;［Ca²⁺］i;spermatogenic cells;iradiation