Redox status and oxidative stress during late pregnancy and postpartum period in mares

This study aimed to evaluate the redox status and oxidative damage of proteins and lipids in mares during late pregnancy, at foaling and during early postpartum period. Blood samples were weekly collected from ten mares during the last trimester of pregnancy until the third week postpartum. Redox status was assessed as oxidant status (TOS) and total antioxidant capacity (TAC), together with nitric oxide radical (NO•) metabolite (NOx) content. Moreover, the indirect parameter oxidative stress index (OSI), representing the TOS/TAC ratio, was calculated and accepted as indicator of redox balance. Oxidative damage of lipids and proteins was assessed as thiobarbituric acid reactive substances (TBARS) and advanced oxidation protein products (AOPP), respectively. One-way analysis of variance for repeated measures showed that some biomarkers (TOS, TAC, OSI and NOx) were affected by the sampling time, showing significant differences around parturition and the first week after foaling. Our results demonstrated that TBARS and AOPP showed no change during the experimental period, although a tendency (P = 0.084) in AOPP levels was shown. The obtained results showed that mares included in this study experienced a transient redox potential imbalance during the postpartum period, which did not result in oxidative damages to lipids and proteins.