We studied the peculiarities of the expression of TLR4 and its inhibitor Tollip in placentas obtained from women aged 23-40 years with early- and late-onset preeclampsia. Histological examination of placental tissue (hematoxylin and eosin staining) and immunohistochemical analysis with primary monoclonal antibodies to TLR4 and Tollip were performed on serial paraffin sections. It was found that the expression of TLR4 increased with increasing gestation term in both the syncytiotrophoblast and vascular endothelium of the placental villi (p<0.05). The expression of TLR4 in syncytiotrophoblast and in the endothelium in early preeclampsia was also significantly (p<0.00001) higher than in the reference group (preterm birth before 34 weeks gestation). In the vascular endothelium of placental villi, the expression of TLR4 in placentas from women with early-onset preeclampsia was higher than in late-onset preeclampsia (p=0.002), while Tollip was lower in early-onset preeclampsia than in the reference group. In preeclampsia, especially in early-onset preeclampsia, marked changes in the expression of TLR4 and Tollip in the placental tissue were detected; the severity of preeclampsia correlated with the degree of damage to the placental villi.
Keywords: TLR4; Tollip; early preeclampsia; placenta; pregnancy.