弓形虫Chinese 1基因型虫株感染对小鼠海马体细胞超微结构的影响

Ultrastructural observations of hippocampal cells in mice infected with Chinese 1 dominant genotype strain of Toxoplasma gondii

目的观察弓形虫Chinese 1优势基因型TgCtwh3和TgCtwh6虫株对小鼠海马体细胞超微结构的影响。方法6周龄的雌性C57BL/6小鼠随机分为3组:对照组、TgCtwh3感染组、TgCtwh6感染组,每组6只。对照组腹腔注射无菌PBS;TgCtwh3感染组腹腔注射4000个TgCtwh3速殖子,饲养6 d;TgCtwh6感染组灌胃20个TgCtwh6包囊,饲养6周。所有动物经取材、制片,并用透射电子显微镜观察。结果与对照组相比,TgCtwh3感染组海马体细胞出现核皱缩坏死,胞质、轴突肿胀,细胞器消失,轴索断裂等病理变化。与对照组相比,TgCtwh6感染组海马体细胞出现线粒体肿胀、空泡化、嵴断裂消失、膜破裂,脂褐素沉积,高尔基体扩张等病理变化。结论TgCtwh3和TgCtwh6感染小鼠均出现海马体细胞超微结构的改变,TgCtwh3感染组多表现为不可逆的细胞坏死,而TgCtwh6感染组表现出线粒体结构破坏为主的慢性细胞损伤,这为探讨弓形虫脑病的致病机制奠定基础。

Objective To observe the effects of TgCtwh3 and TgCtwh6,Toxoplasma gondii of Chinese 1 dominant genotype,on the ultrastructure of hippocampal of mice.Methods Six-week-old female C57BL/6 mice were randomly divided into three groups:control group,TgCtwh3 infection group and TgCtwh6 infection group,with 6 mice in each group.Control group was intraperitoneally injected with sterile PBS.The TgCtwh3 infected group was intraperitoneally injected with 4000 TgCtwh3 Toxoplasma gondii tachyzoites and fed foR6 days.The TgCtwh6 infected group was given 20 TgCtwh6 Toxoplasma gondii cysts by gavage and fed foR6 weeks.Then,all the animals were sacrificed,the brains were obtained foRpreparing electron microscope specimens and observed.Results Compared with the control group,the cells in hippocampal of TgCtwh3 infected group showed nucleaRshrinkage and necrosis;cytoplasmic and axon swelling;organelle disappearance;axonotmesis and otheRpathological changes.Compared with the control group,the cells in hippocampal of TgCtwh6 infected group showed swollen,vacuolated,crista-broken oRmembrane-broken mitochondria;lipofuscin deposition;dilation of golgi apparatus and otheRpathological changes.Conclusion Both TgCtwh3 and TgCtwh6 infected mice showed ultrastructural changes in hippocampal compared with normal mice.The TgCtwh3 group showed irreversible cell necrosis,while the TgCtwh6 group showed chronic cell damage mainly caused by mitochondrial structure destruction.These results lay a foundation to explore the pathogenesis of toxoplasmosis.