犬弓首蛔虫卵体外发育的形态观察

Morphological observations of Toxocara canis egg development in vitro

为了研究犬弓首蛔虫卵的体外发育形态学变化,采用显微自动拍照系统对体外培养的犬弓首蛔虫卵进行了连续21 d观察和记录。结果表明,犬弓首蛔虫卵存在12个体外发育阶段,即1细胞期、2细胞期、3细胞期、4细胞期、早期桑甚期、晚期桑甚期、囊胚期、肠胚期、1期幼虫前期、1期幼虫期、2期幼虫前期和2期幼虫期。观察发现,虫卵在培养24 h后开始出现卵裂,形成2细胞期虫卵;虫卵第3~6天陆续发育形成3-4细胞期、桑菖期、囊胚期以及肠胚期虫卵;第7天,22.5%虫卵发育形成1期幼虫,并表现出一定趋光特性;第8天,10.67%虫卵发育形成感染性2期幼虫;第17天,感染性2期幼虫从虫卵孵出,卵壳塌陷。这些结果补充和完善了犬弓首蛔虫卵的体外发育形态变化资料。

To observe the morphological changes of Toxocara canis egg development, an automatic microscopic photographing system was setup to track and record the whole process of T. canis egg development during continuous 21 -day egg culture in vitro in this study. The results demonstrated that the whole development of T. canis egg in vitro was divided into 12 developmental stages including one-cell, two-cell, three-cell, four-cell, early-morula, late-morula, blastula, gastrula, pre-larva, LI (the first stage larva), pre?L2 and L2 stages. The cell started to divide to form two-cell egg in 24 hours culture, appeared as 3-4 cells egg, morula, blastula and gastrula stages in 3-6 days. Total 22.5% of eggs developed to embryonated LI with phototactic movements in 7 days. Total 10.67% eggs developed to infective embryonated L2 in 8 days. At 17-day post culture, the infective larva have been hatched and the whole eggshell collapsed. These data provide more information for the developmental biology of T. canis egg in vitro.