The Influence of Hormones on the Bacterial Flora of the Murine Vagina and Implications for Human Disease

Oestradiol or progesterone administered to groups of young female B’alb C mice affected their reproductive cycle compared to that of untreated mice. The cycle of oestradiol-treated mice arrested in the oestrous phase within about 24 h and there was a concomitant increase in the bacterial flora of the vagina with many epithelial cells studded with bacteria. However, progesterone-treated mice required longer to arrest the cycle in the dioestrous phase with virtual disappearance of bacteria. The similarities between the features of the oestradiol-stimulated events in mice and those of bacterial vaginosis in women suggest that the latter condition might be stimulated hormonally. Keywords: Hormones; Vaginal flora; Mouse vagina.