Scanning electron microscopic observation of interactions of vaginal epithelial cells with Candida albicans and Lactobacillus crispatus

Abstract

Objective: To investigate interactions of vaginal epithelial cells (VEC) with Candida albicans and the protective effect of Lactobacillus crispatus on VEC. Methods: VK2/E6E7 VEC cell line was cultured. Candida albicans and Lactobacillus crispatus suspension were prepared respectively. Ultrastructural morphological changes of VEC infected with Candida albicans and treated with Lactobacillus crispatus were observed by scanning electron microscope (SEM). Results: Candida albicans invaded into VEC mainly through endocytosis after an early infection of 6 hours. Pseudopods of VEC increased, contacted and covered the surface of pseudohyphae. After 12 hours infection, active penetration developed into the predominant invasion mechanism. Candida albicans directly penetrated through VEC, destroyed the surface structures, and even led to cell death. A reduction of pseudopods on VEC was observed. After co-incubation with Lactobacillus crispatus, SEM revealed a morphological recovery of VEC and destruction of pseudohyphae. Conclusion: s Candida albicans invade VEC mainly through endocytosis and active penetration. Lactobacillus crispatus could utilize occupying effect to exert protective effect on VEC during the infection with Candida albicans.