Toll-like receptor 2 and 4 expression in the pregnant and non-pregnant human uterine cervix

• We demonstrated the expression of TLR2 and TLR4 in human cervical tissue.
• We have shown that pregnancy causes a significant increase in TLR2 and TLR4 expression in cervical epithelium.
• We hypothesise that hormonal influences associated with pregnancy may be pivotal to these changes.

Pelvic infections and sexually transmitted diseases place a burden on health resources and may be associated with premature birth. The mechanisms by which the female reproductive tract (FRT) combats these infections remain ill understood, but are likely to involve the pattern recognition Toll-like receptors (TLR). We sought to compare the expression of TLR-2 and -4 by human pregnant and non-pregnant ectocervical epithelium as a prelude to the investigation of the function of these receptors in this tissue during pregnancy. Using the techniques of reverse-transcriptase polymer chain reaction (RT-PCR) and immunohistochemistry, the gene and protein expression of TLR-2 and -4 were studied in the biopsies of ectocervix obtained from non-pregnant premenopausal women (n = 21) undergoing hysterectomy, women in the first trimester of pregnancy undergoing non-medically indicated suction pregnancy termination (n = 6), and women at term undergoing elective caesarean section (n = 11). The expression of TLR2 and TLR4 genes and proteins were upregulated in early and late pregnant ectocervical epithelium, compared with non-pregnant tissue. These findings suggest that the upregulation of TLR2 and TLR4 in the lower FRT may play a key role in the modulation of the innate immune and inflammatory mechanisms of the ectocervix during pregnancy, interacting with other neuroendocrine factors.