[Ultrastructural pathological observation of vaginal inflammatory mucosal injury induced by Candida albicans infection and the restorative effect of Lactobacillus crispatus].

Objective

To establish a rat model of vulvovaginal candidiasis (VVC) and to directly observe the histopathological and ultrastructural characteristics of vaginal mucosal barrier after Candida albicans infection and treatment with Lactobacillus crispatus.

Methods

Female unmated SD rats were used to establish the VVC model and divided into three groups (normal group, VVC group, and Lactobacillus group; n=6 per group). Lactobacillus group received intravaginal administration of Lactobacillus crispatus suspension, while rats in VVC group and normal group were infused with phosphate buffered solution instead. Vaginal tissues were collected on day 4 post-treatment for HE staining and transmission electron microscopy (to observe ultrastructural pathological changes).

Results

The results of HE staining revealed the disruption and desquamation of vaginal epithelium, necrotic epithelial tissues, neutrophil infiltration in Candida albicans-infected rats. Lactobacillus crispatus intervention restored the damaged vaginal mucosal structure (mucosal layers and thickness) to normal levels, mucosal layers of Lactobacillus group and normal group were 9.50±1.38 vs 10.67±1.03 (P=0.226), mucosal thickness of Lactobacillus group and normal group were (116.50±12.14) vs (130.33±13.91) μm (P=0.211). The results of transmission electron microscopy revealed intercellular desmosome rupture, loss of microvilli and glycocalyx on superficial cells, and mitochondrial swelling in Candida albicans-infected rats. Lactobacillus crispatus intervention restored the damaged vaginal mucosal ultrastructures (mitochondria and intercellular connections, etc.) to normal levels.

Conclusions

Fungal infection severely disrupte the vaginal mucosal barrier in rats. Lactobacillus crispatus could restore the vaginal mucosal barrier and epithelial ultrastructures.