Investigating the role of inflammation on bovine oocyte health and development

Abstract

In this study we investigated the effects of inflammation resulting from LPS exposure on oocyte health, maturation and subsequent developmental competence. Inflammation caused by infection in cattle is known to have negative impacts on reproduction and subsequent production efficiency. However, the mechanisms of action and the extent of damage remain to be well defined. Lipopolysaccharide (LPS) is a component of the bacterial cell wall of gram-negative bacteria such as E. coli and is known as the activator of the toll-like receptor 4 (TLR4) pathway and subsequent immune response. We hypothesize that granulosa cells are able to directly respond to an LPS challenge and that the response may perturb oocyte health and developmental competence. Here we explore the ability of ovarian cells to respond to LPS via an inflammatory immune response in addition to the impacts of inflammation on the health and maturation of bovine cumulus-oocyte-complexes (COCs) treated with LPS and/or the TLR4 inhibitor, TAK-242, as a means of activating an innate immune response and to elucidate the potential role the TLR4 pathway plays in this process. In conclusion, we found that ovarian cells are capable of mounting an inflammatory immune response in the presence of LPS via an increase in the expression of inflammatory cytokine markers. Additionally, LPS treated COCs demonstrated decreases in oocyte health marker expressions and poorer maturation outcomes.