Antioxidative defence mechanisms in bovine placenta and their importance for placental release

Reactive oxygen species, although unavoidable intermediates, may have positive and negative effects on tissue and cells. There is some evidence that imbalance between production and neutralization of reactive oxygen species may lead to peroxidative changes of cells, disturbances of the metabolism and in consequence disorders such as, among others, the retention of fetal membranes, udder oedema and mastitis in cows. Defence mechanisms against reactive oxygen species consist of enzymatic and nonenzymatic systems. This review examines the available literature regarding the activity of enzymatic and nonenzymatic defence mechanisms against reactive oxygen species in bovine placenta. Its importance for placenta release in cows is also discussed.