Effects of Wharton's jelly mesenchymal stromal/stem cells-derived conditioned medium and platelet-rich plasma on in vitro induced equine endometrial inflammation

Over the years, regenerative therapies have emerged as promising alternatives for persistent breeding-induced endometritis. In vitro studies testing the effects of these therapies on equine endometrial cells are still scarce. This study aimed to evaluate in vitro the effect of Wharton's jelly (WJ) mesenchymal stromal/stem cell (MSCs)-derived conditioned medium (WJ-CM) and platelet-rich plasma (PRP) on equine endometrial cells, with or without lipopolysaccharide (LPS)-induced inflammation. The WJ-CM was obtained after 24 h of starvation in Ringer's lactate of WJ-MSCs and PRP was prepared using the double centrifugation. Endometrial epithelial cells obtained from 3 diestrus mare uteri at slaughterhouse were treated for 24 h according to six experimental groups: DMEM standard complete medium (CTRL); 10 ng/mL LPS (LPS); 10 % WJ-CM (CM); 5 % PRP (PRP); 10 ng/mL LPS and 10 % WJ-CM (LPS + CM); 10 ng/mL LPS and 5 % PRP (LPS + PRP). After 6, 12, and 24 h, endometrial cells were evaluated for viability (apoptosis and necrosis), mitochondrial activity and reactive oxygen species (ROS) generation. PGE-2 and IL-10 concentrations in spent medium were measured. The WJ-CM alone did not affect endometrial cell viability and prevented the detrimental effect of LPS on endometrial cells; it suppressed the production of PGE-2. PRP had a deleterious effect on endometrial cell viability, induced the secretion of PGE-2, as well as increased mitochondrial activity and ROS production. Endometrial benefits of the WJ-CM treatment are evident even after an LPS challenge, while unexpectedly PRP showed a deleterious effect.