[Establishment of a rat model of dimethylbenzanthracene-induced vulvar squamous intraepithelial lesions].

OBJECTIVE: To establish a SD rat model of vulvar squamous intraepithelial lesions.

METHODS: Seventy female SD rats were randomized into 4 groups, namely the blank control group ( n =10), mechanical irritation group ( n =10), acetone solution group ( n =10), and mechanical irritation with DMBA acetone solution group ( n =40, model group), and the corresponding treatments were administered 3 times a week for 14 weeks. The changes of the vulvar skin of the rats were observed regularly until the 18th week. The expression of mutant p53 (mtp53) and vascular endothelial growth factor (VEGF) proteins were detected using immunohistochemistry and Western blotting, and the expressions of mtp53 and VEGF mRNA were detected with qRT- PCR in the blank control group and model group.

RESULTS: No significant differences were found in the morphological or histopathological changes of the skin among the blank control group, mechanical irritation group and acetone solution group. In the model group, low-grade squamous intraepithelial lesions (LSIL) occurred in 28 rats (70%) and high-grade squamous intraepithelial lesions (HSIL) in 11 rats (27.5%) at 14 weeks, with a success rate of 97.5% in inducing vulvar squamous intraepithelial lesions. Compared with the blank control group, the rats in the model group showed significantly increased expressions of mtp53 and VEGF at both the protein level ( P < 0.05) and the mRNA level ( P < 0.05).

CONCLUSIONS: DMBA in acetone solution combined with mechanical irritation can induce vulvar squamous intraepithelial lesions in female SD rats.