Co-localization of oestrogen receptor β and leukocyte markers in the human cervix

Cervical ripening during parturition is associated with rapid production of catabolic enzymes by invading leukocytes and increased collagen metabolism. The recruitment of leukocytes is regulated by various factors including inflammatory mediators, prostaglandins and matrix metalloproteinases. Sex steroids may be indirectly or directly involved in this process. This study aimed to evaluate the expression of oestrogen receptor beta (ERP) in blood cells infiltrating the cervix during pregnancy and parturition. Cervical biopsies were obtained from term pregnant, postpartal and non-pregnant women. The ERP protein and leukocyte markers CD45 and CD68 were evaluated by single and double labelling immunohistochemistry. Quantitative values were assessed using a microscope and a high-resolution camera connected to a computer with image analysis program. The number of CD45(+) and CD68(+) cells in the cervix increased in term pregnancy and post-partum. compared with the non-pregnant state. The ERP antigen was co-localized with CD45 leukocyte common antigen and CD68 macrophage specific antigen in blood leukocytes infiltrating the cervical tissue. The presence of ERP in the cervical leukocytes suggests that oestrogen may directly regulate leukocyte functions in the cervix.