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 µg/100 µL/mouse) or physiological saline (100 µL) via laparotomy. Uterine cervices and blood were sampled immediately postpartum. As a result, epithelial PR and muscular ERα 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 ERα-to-PR expression ratio in the proximal cervix was associated with preterm labour and delivery. ERα 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.

• What are the implications of these findings for clinical practice and/or further research? This study revealed the differences between the roles of sex hormones and their receptors in epithelial and muscle layers of proximal and distal cervices in preterm labour and delivery.

Keywords:

• Preterm birth
• cervical excision
• progesterone
• oestrogen
• proximal cervix

Acknowledgements

Technical support was provided by the Core Laboratory for Convergent Translational Research in College of Medicine, Korea University, Seoul, South Korea.

Disclosure statement

The authors report no conflict of interest.

Additional information

Funding

This research was financially supported by the Basic Science Research Programme through the National Research Foundation of Korea (NRF-2014R1A1A1002300 and NRF-2018R1D1A1B07046332) and a grant from Korea University Medical Centre and Anam Hospital, Seoul, Republic of Korea (Grant No. K1620211 and K1807761). The funding source did not affect the results of this study.