Maternal metabolic stress may affect oviduct gatekeeper function.

Area of Science:

• Reproductive Biology
• Cellular Metabolism
• Animal Science

Background:

• Non-esterified fatty acids (NEFA) are crucial for cellular energy but can disrupt cell function at elevated levels.
• The bovine oviduct epithelial cells (BOEC) play a critical role in early embryo development and maternal recognition of pregnancy.
• Understanding how NEFA affects BOEC function is vital for improving reproductive outcomes in cattle.

Purpose of the Study:

• To investigate the effects of elevated NEFA on *in vitro* bovine oviduct epithelial cell (BOEC) metabolism and barrier function.
• To determine how the location of NEFA exposure (apical vs. basal) influences BOEC responses.
• To elucidate the cellular mechanisms by which NEFA modifies BOEC physiology.

Main Methods:

• BOECs were cultured in a polarized system and treated with varying concentrations of NEFA.
• Monolayer permeability was assessed using FITC-albumin flux and transepithelial electric resistance (TER).
• Metabolite concentrations, intracellular lipid accumulation, fatty acid transporter expression, and gene expression were analyzed.

Main Results:

• Apical NEFA exposure significantly reduced barrier integrity (TER) and increased permeability (FITC-albumin flux).
• Basal NEFA exposure led to the transfer of free fatty acids to the apical compartment.
• Apical NEFA induced intracellular lipid droplet accumulation and upregulated fatty acid uptake and metabolism-related genes.

Conclusions:

• Elevated NEFA differentially affects BOEC metabolism and barrier function based on the site of exposure.
• The bovine oviduct acts as a gatekeeper, potentially modulating the uterine environment by altering NEFA exposure to the early embryo.
• These findings highlight the importance of managing NEFA levels for optimal bovine reproductive health.