Exposure to an Environmentally Relevant Phthalate Mixture Impairs Ovarian Endothelial Cell Function In Vitro

Phthalates are ubiquitous, endocrine-disrupting chemicals used as plasticizers and solvents in many consumer goods. Phthalates are metabolized within the body to bioactive metabolites, which have been found in human follicular fluid. Previous work has shown that exposure to phthalates reduces ovulation rates and decreases levels of ovulatory prostaglandins (PGs) in rodent and human cell models. As such, phthalate exposure could impair ovulation by disrupting downstream PG-mediated ovulatory events, like angiogenesis. This study utilized a primary population of mouse ovarian endothelial cells to test the hypothesis that exposure to a mixture of phthalate metabolites (MPTmix) disrupts angiogenic receptor levels, viability, and functional events associated with angiogenesis, specifically proliferation and migration. Endothelial cells were treated ±MPTmix (1-500μg/ml; DMSO=vehicle control) and ±vascular endothelial growth factor A (VEGFA; 5ng/ml; angiogenic stimulus) for 24 or 48hr. MPTmix exposure altered endothelial cell expression of angiogenic receptors (Ptger4, Flt1, Kdr, Flt4, Ednrb, Tek, Nrp1) and decreased viability under basal (-VEGFA) and supplemented (+VEGFA) conditions. This decrease in viability was due to apoptosis in the basal state, but there were no changes in levels of reactive oxygen species and antioxidant capacity under both conditions. Despite this, the reduced viability and changes in angiogenic receptor expression contributed to impaired angiogenic outcomes. MPTmix exposure reduced proliferation and migration under supplemented conditions. Taken together, MPTmix exposure may threaten angiogenic events that occur during ovulation by impairing endothelial cell function. These findings, using a cell type not commonly investigated in ovarian/reproductive toxicology, highlight the negative impacts of phthalate exposure on ovarian function.