Isorhamnetin Ameliorates Non-Esterified Fatty Acid-Induced Apoptosis, Lipid Accumulation, and Oxidative Stress in Bovine Endometrial Epithelial Cells via Inhibiting the MAPK Signaling Pathway.

High concentrations of non-esterified fatty acids (NEFA) in the blood contribute to various metabolic disorders and are linked to endometritis in dairy cows. Isorhamnetin (ISO), a flavonoid found in many plants, is known for its antioxidant, anti-inflammatory, and anti-obesity properties. This study systematically assessed NEFA-induced damage in bovine endometrial epithelial cells (bEECs) and investigated whether ISO alleviates NEFA-induced cell damage and its underlying molecular mechanisms. Our observations revealed that excessive NEFA inhibited proliferation and induced apoptosis in bEECs, accompanied by an increase in the expression of BAX and cleaved caspase-3. We further observed that NEFA could induce lipid accumulation, reactive oxygen species (ROS) generation, and the release of pro-inflammatory factors IL-1β, IL-6, and TNF-α in bEECs. RNA sequencing and Western blot analysis revealed that NEFA induced damage in bEECs by activating MAPK signaling pathway. Notably, ISO treatment ameliorated these effects induced by NEFA, as evidenced by decreased protein levels of BAX, cleaved caspase-3, and PPAR-γ, along with reductions in triglyceride content, ROS generation, and levels of IL-1β, IL-6, and TNF-α. Mechanistically, our experimental results demonstrated that ISO inhibited NEFA-induced activation of MAPK signaling. Overall, ISO shows promise for therapeutic development to address NEFA-related endometritis in dairy cows.