Expression and significance of aquaporin-2 in human ectocervical-vaginal epithelial cells

To observe the expression of aquaporin-2 (AQP2) in human ectocervical-vaginal epithelial cells (hECEs).

The study included 75 females who underwent hysterectomy for benign pelvic lesions. They were divided into three groups according to menstrual states: 28 cases in the normal menstrual group, 24 cases in the perimenopausal group, and 23 cases in the postmenopausal group. Specimens were obtained from the posterior vaginal wall. AQP2 mRNA and protein expression were detected using quantitative real-time polymerase chain reaction and immunohistochemistry, respectively. Estrogen (E2), follicle-stimulating hormone (FSH) and plasma osmolality were assayed by blood routine test. Linear regression analysis was used for data analysis.

AQP2 mRNA and protein expression were detected in all hECE tissues. AQP2 mRNA and protein expression in the normal menstrual group were significantly higher than those in the peri- and menopausal groups (p < 0.05). AQP2 mRNA was negatively correlated with FSH level (R = -0.537, p < 0.05), age (R = -0.508, p < 0.05) and plasma osmolality (R = -0.214, p < 0.05), but positively correlated with E2 (R = 0.511, p < 0.05). AQP2 protein expression was negatively correlated with FSH (R = -0.419, p < 0.05) and age (R = -0.034, p < 0.05), but positively correlated with E2 (R = 0.367, p < 0.05).

The downregulation of AQP2 might be a causative factor for decreased vaginal secretions during the menopausal period.