Effects of Long-Term Implantation of Vaginal Concretions on the Cervicovaginal Epithelium of Mice 1

Abstract

Abstract

In two experiments, neonatal female BALB/cCrgl or BALB/cfC3HCrgl mice were given subcutaneous injections of 5 μg 17β-estradiol or sesame oil for the first 3 days of life and were ovariectomized at 60 days of age, at which time vaginal concretions (Experiments I and II) or silica (Experiment II) were implanted intravaginally. Mice were examined at 12 months of age. Three abnormal cervicovaginal epithelial responses were noted: persistent vaginal stratification/cornification (PVS); prominent vaginal squamocolumnar junction (SCJ); epithelial pegs, downgrowths, or lesions (dysplasias). PVS, not present in unimplanted controls, occurs in at least half of the members of the neonatally estrogen-treated groups; implants of concretions or silica did not increase its incidence significantly. Although SCJ was observed in implanted but not in unimplanted controls, its incidence was significantly higher in neonatally estrogen-treated mice than in either control group. The elevated incidence in neonatally estrogen-treated mice was not increased further by implantation of concretions or silica. In neonatally estrogenized mice, the subsequent implantation of a concretion significantly increased the incidence of cervicovaginal abnormalities. Increased PVS and SCJ are teratological consequences of neonatal exposure to a small amount of estrogen; on the other hand, increased dysplasias may, in part, be responses of the estrogenized vaginal epithelium to the concretions.