Effect of ovarian cycle on TLR4 mRNA expression pattern in ampulla and isthmus of the bovine oviduct

This study was conducted to evaluate the TLR4 gene expression's pattern in ampulla and isthmus of dairy cows during the ovarian cycle. The ovarian cycle phase was determined based on the appearance, size, and color of corpus luteum and dominant follicle. The TLR4 expression was assessed in ampulla and isthmus of 40 oviducts using qRT-PCR. Results showed at the pre-ovulatory phase, TLR4 gene expression in the isthmus of ipsilateral oviducts was significantly greater than that in ampulla. Also, the expression of TLR4 in ampulla and isthmus of the oviducts ipsilateral to the pre-ovulatory ovary was significantly greater than that in the ampulla and isthmus of oviducts contralateral to the post-ovulatory or mid-cycle ovaries. In general, the present study showed that, TLR4 mRNA expression was differentially influenced by the stage of the ovarian cycle, its relation to the functional ovary, and the oviductal parts (ampulla or isthmus) in bovine.