Effect of lipopolysaccharide on developmental competence of oocytes.

In postpartum dairy cows, lipopolysaccharide (LPS) derived from gram-negative bacteria such as Escherichia coli causes uterine inflammation resulting in low fertility. The aim of this study was to determine the effect of LPS on the developmental competence of bovine oocytes in vitro. LPS perturbed the nuclear maturation of bovine oocytes by inhibiting meiotic progression. Although LPS did not affect the copy number of mitochondrial DNA, it decreased mitochondrial membrane potential in matured oocytes. LPS inhibited mitochondrial redistribution throughout the cytoplasm. Oocytes matured under LPS treatment showed decreased development to the blastocyst stage. Moreover, the trophoblast cell number of blastocysts was significantly lower when the oocytes were matured in the presence of LPS. Our findings suggest that LPS might impair the nuclear and cytoplasmic maturation of oocytes and obstruct subsequent embryonic development in dairy cows.