Palmitic acid stimulates interleukin-8 via the TLR4/NF-κB/ROS pathway and induces mitochondrial dysfunction in bovine oviduct epithelial cells.

Abstract

We investigated the effect of palmitic acid (PA), a major saturated fatty acid in NEFA, on bovine oviduct epithelial cells (OECs) during in vitro cell culture. Bovine oviductal tissues ipsilateral to the corpus luteum were collected 1-3days after ovulation; the OECs were isolated and cultured. PA increased lipid accumulation and activated caspase-3 in OECs, resulting in decreased cell proliferation. PA also stimulated the secretion of inflammatory cytokine interleukin (IL)-8 depending on TLR4, NF-κB activation, and reactive oxygen species (ROS) production. Moreover, PA induced mitochondrial dysfunction, including mitochondrial fission, ATP production, and mitochondrial ROS production. It also increased levels of LC3 and p62 proteins, suggesting autophagy induction in OECs. We suggest that bovine OECs recognize an excessive increase in endogenous and sterile danger signals, such as PA, which may contribute to chronic oviductal inflammation, resulting in infertility associated with oviductal dysfunction.