Ischemia-reperfusion injury in ovaries

Abstract

Introduction. Ovarian torsion is a condition in which the ovary twists around its pedicle resulting in diminished blood flow with the ischemia of the organ. It is the fifth most common cause of acute abdomen in women and requires detorsion to treat. Following reperfusion a cascade of reactions is initiated with the formation of reactive oxygen and nitrogen species (ROS, RNS), which lead to cell injury. Aim of the study. To determine the effects of ischemia-reperfusion injury on ovarian viability and later fertility in patients with ovarian torsion. Materials and methods. Studies from the specialized journals of PubMed, Medline, Hinari were used, which focused on the structural and functional changes in detorsioned ovaries, their viability, follicular reserve and fertility. Results. Ischemia in torsioned ovaries leads to the formation of ROS and RNS such as superoxide anion radicals, nitric oxide and others. Following reperfusion the influx of large amounts of oxygen leads to the increase of ROS production which causes inflammation and tissue damage. Therefore the damage to the tissue is exponentially more severe in the reperfusion rather than in the ischemic phase. ROS are responsible for the peroxidation of the membrane lipids with the formation of malonic dialdehyde (MDA), increased cell membrane permeability, DNA chain breaks and mutations, massive influx of Ca2+ from its binding sites with the release of cytochrome c from the mitochondria and activation of caspase-dependent cell death. These free radicals are scavenged by the antioxidant enzymes, such as superoxide dismutase, catalase and by vitamin C, which seems to be present in high concentrations in the ovary and can help partly minimize the cell damage. Studies in patients with ovarian torsion show that the majority of detorsions are successful even in later stages with the recovery of normal blood flow and the preservation of the organ structure. Follicular reserve has also been shown to be maintained even after prolonged periods of ischemia. Few studies are available for the fertility of these patients, but nonetheless they show pregnancies in the majority of cases. Conclusions. The ovary seems to possess a certain degree of resistance to ischemia-reperfusion injury even after long periods of ischemia as shown by the preservation of its structure, follicular reserves and fertility, but further studies are required to assess all of the consequences. Thus, conservative treatment of ovarian torsion is encouraged with gradual detorsion of the organ.