Epigenetic regulation of collagen in the mare's placenta: putative relationship with maternal age

Placental plasticity influences fetal development, pregnancy success, and foal growth. Older fertile mares deliver heavier foals and placentas, with increased collagen deposition. In humans, epigenetics regulates placental development and function. Epigenetics, through DNA methylation, also modulates endometrial fibrosis. As such, we hypothesized that as mares get older, collagen deposition in the placenta might be epigenetically modulated. This study assessed if transcription of collagen genes in the equine placenta was epigenetically modulated through DNA methyltransferases (DNMTs), and affected by aging. Immediately after foaling, samples from different chorioallantoic areas (gravid horn, non-gravid horn, and body) were collected from young (n=10; 4-6 years) and older mares (n=10; 12-18 years). Gene transcription of collagen type 1 (COL1A1), collagen type 3 (COL3A1), and DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) was determined (qRT-PCR). Unpaired T-test and Mann-Whitney test were used with statistical significance set a p