Melatonin Attenuates Peroxynitrite-Induced Meiosis Dysfunction in Porcine Oocytes

A high level of reactive oxygen species (ROS) is widely considered one of the major causes of oocyte quality decline. Peroxynitrite is known as a powerful oxidant, which could induce multiple physical diseases. Recently, emerging pieces of evidences indicate that melatonin effectively promotes the development of oocytes, although the specific work mechanism remains to be further clarified. In this study, it was shown that peroxynitrite increased the level of ROS in porcine oocytes, which induced the apoptosis of oocytes, thereby leading to the obstruction of spindle assembly, depolymerization of actin, and decrease of polar body expulsion. These negative effects contributed to the failure of meiosis and ultimately blocked the maturation of porcine oocytes. As expected, it was found that melatonin effectively removed the accumulated ROS in oocytes, preventing oocytes from peroxynitrite-induced oocyte maturation failure, which might provide a novel approach to improve female livestock reproduction and cure female infertility in clinical practice.