^(60)Coγ射线对刚地弓形虫缓殖子感染性的影响

EFFECT OF ^(60)Coγ-IRRADIATION ON THE INFECTIVITY OF TOXOPLASMA GONDII BRADYZOITES

应用不同剂量的^(60)Coγ射线照射含NT株弓形虫包囊的鼠脑匀浆后,以0.4％胰蛋白酶液消化,使弓形虫缓殖子从包囊中释放出来,并用生理盐水作连续10倍稀释,使成为含不同数量缓殖子的悬液,将此悬液接种小鼠,用生物检测方法确定其感染性。另设未经照射处理的缓殖子悬液感染小鼠的对照组。结果表明,γ射线0.55kGy剂量为控制鼠脑中NT株弓形虫感染性的最小有效剂量。γ射线0.1kGy剂量对弓形虫缓殖子感染性无明显影响,而0.45kGy照射后,其感染性较前者下降了10~4倍。

Homogenates of mouse brains harbouring toxoplasma NT strain cy-sts were irradiated at various doses of ^(60)Co γ ray and digested with 0.4% trypsinbuffer to release bradyzoites from cysts. The suspensions containing various numberbradyzoites were obtained through a serial 10-fold dilution in saline solution andinoculated intraperitoneally into mice separately. Infeetivity of toxoplasma bradyzoiteswas determined by bioassay of mice. A group of mice inoculated with non-irradiatedbradyzoites was used as control. Results showed that the minimal effective dose ofγ rays controlling infectivity of toxoplasma NT strain bradyzoites was 0.55 kGy.Effect of 0.1 kGy γ rays on infectivity of toxoplasma bradyzoites, was not signifi-cant. Infectivity of bradyzoites irradiated at 0.45 kGy had 10~4 fold reduction in com-parison with that of 0.1 kGy.