Culture systems for transformations of hydatid cysts from protoscoleces in vitro

Abstract

Objective To search for a suitable culture system for transforming protoscoleces of Echinococcus granulosus into hydatid cysts in vitro. Methods Based on the basic cell culture media RPMI1640 or DMEM, and fetal calf serum or sheep serum as nutrients, and human liver cell line L02 as server cells, culture systems for transformations of protoscoleces into hydatid cysts in vitro were established based on block designs. The culture systems were divided into 2 main groups, and 6 subgroups according the different ingredients of culture media, sera, and sever cells. The protoscoleces were cultured in 6 subgroups for 45 d, and then the most suitable medium for the transformations was screened according to the ratios of evaginated or encysted protoscoleces, and the sizes of protoscoleces. In the selected best culture system, the encysted protoscoleces were kept cultivating up to 180 d for further observation. Results Within the first period of 45 d, it demonstrated that the culture system of DMEM medium+fetal calf serum+L02 cells was the best culture system for transformations of protoscoleces into hydatid cysts in vitro, because of the fastest growth speed of protoscoleces, the maximal ratio of encystation of protoscoleces since 20 d (P < 0.05), the biggest size of hydatid cysts since 25 d (P < 0.05), and 100% percentage of encystation of protoscoleces at 45 d. In the following culture days (46 to 180 d), the hydatid cysts still grew up, the transparent hydatid cysts were visible to the naked eyes at 80 d, and the biggest cyst size reached to 2.2 mm at 180 d. Conclusion The culture medium of DMEM, added with fetal calf serum and L02 cells, is a suitable culture system for transformations of protoscoleces into hydatid cysts in vitro.

Keywords

• echinococcus granulosus
• protoscoleces
• encystation
• hydatid
• culture system