Role of sex hormones in cervical changes in a cervical excision-related preterm delivery mouse model

Abstract

Progesterone and oestrogen play important roles during parturition; however, their roles in the uterine cervix during preterm labour and delivery are unknown. We evaluated the serum progesterone and oestrogen levels and changes in their receptors (PR and ER) in the cervix in a cervical excision-associated preterm delivery mouse model. Adult female C57BL/6 mice were divided into four groups: sham, cervical excision (Ex), lipopolysaccharide (LPS) and Ex + LPS. Mating was permitted at 3 weeks post-Ex. On gestation day 16, mice were administered LPS intrauterine (100 mu g/100 mu L/mouse) or physiological saline (100 mu L) via laparotomy. Uterine cervices and blood were sampled immediately postpartum. As a result, epithelial PR and muscular ER alpha were down- and upregulated, respectively, in the proximal cervix in Ex + LPS group compared to in the sham group. These results indicate that unique sex hormone effects are exerted on the uterine cervix during cervical excision-associated spontaneous preterm labour and delivery.Impact statement What is already known on this subject? Preterm and term parturition require the withdrawal of progesterone and the activation of oestrogen in the uterine body and systemic levels. However, we have little understanding of the role of the sex hormones in the uterine cervix. What do the results of this study add? Increased ER alpha-to-PR expression ratio in the proximal cervix was associated with preterm labour and delivery. ER alpha expression in the smooth muscle layer of the proximal cervix was higher and PR expression in the proximal cervix epithelium was lower during preterm labour and delivery.