Degenerative changes of the endometrium are directly related to age and fertility in mares. Chronic degenerative endometritis (CDE) is correlated with uterine fluid retention and reduced ability to clear uterine inflammation. The presence of E. coli and LPS (endotoxins) in lochia early postpartum favor the development of uterine infections. A study was conducted to investigate the relationship between intra-uterine bacterial contamination, endotoxin levels and the development of endometritis in cows that experienced a dystocia or retained their placenta.
As we know Endometritis reduces fertility, and it causes a great economic loss in animal agriculture for what concern beef and dairy. At the same time persistent mating-induced endometritis (PMIE) results in decreased fertility in horses. The reduce of fertility in horses can drastically reduce the success rate of artificial inseminations, causing important economic loss when we speak about semen of high value studs.
In fact, meta-analysis studies show that endometritis reduces pregnancy rate by 16 %.
Approximately, 80 % to 100 % of cows have intrauterine bacterial contamination in the first two weeks postpartum. In most cases, clinical disease does not develop, but in the remaining percentage, 10% or 20% of cows, the infection may lead to chronic uterine inflammations.
In cows, many therapeutic agents and procedures have been developed to treat endometritis, including systemic or intrauterine administration of antibiotics, or administration of PGF2α (Prostaglandin F2α) and its analogue, or the Lugol’s solution containing antiseptics, although it seems to produce side-effects on future fertility of the cows.
Platelet-rich plasma (PRP) is a treatment principally used in tissue regeneration due to its enrichment in growth factors with mitogenic and anti-inflammatory potential. In particular the presence of anti-inflammatory molecules, including HGF, confers to PRP the ability to suppress or moderate inflammatory processes.
In the following study the effect of PRP has been investigated in vivo on healthy animals (without endometrial infection) and in an in vitro model where bovine endometrial cells were stressed with LPS.
The results indicate that PRP might be helpful in maintaining and/or increasing the number of progesterone receptors in uterine tissues. In the in vitro experiment, bovine endometrial cells were cultured with two different concentrations of PRP (5 % and 10 %). Especially in the concentration of 5%, the PRP was able to increase cell proliferation also in endometrial cells.
Data indicates that PRP have strong effects on endometrial cells determining high proliferation rate and up-regulation of genes that play an important role in reproduction.
In fact, for some years now, PRP has been widely used in the treatment of Persistent endometritis after breeding (PMIE), demonstrating that uterine infusions of PRP reduce the inflammation. Usually from 10 to 20 ml of autologous PRP is infused into the uterus.4 hours later artificial insemination (AI). Through this application, it was demonstrated that the infusion of PRP reduced the inflammatory response after breeding, specifically in mares susceptible to endometritis (Effect of use of platelet rich plasma on post-breeding uterine inflammatory response of mares, MFS Reghini et al., Journal of Equine Veterinary Science, 2014; 34:127).
In another study, after an infusion of 10 ml of PRP into the uterus, the pregnancy rate of treated mares was compared with controls (not receiving PRP infusion). The pregnancy rate was very different: 67% for the PRP treated Vs the 19% of the controls (not treated with PRP). (The effect of platelet-rich plasma (PRP) on intraluminal fluid and pregnancy rates in mares susceptible to persistent mating-induced endometritis (PMIE). ES Metcalf et al., J. Equine Vet. Sci. (2014); 4:128)