Shrinkage of Vitreous Body Caused by Hydroxyl Radical

Human being gets about 90% of the information via visual sense[1,2]. Therefore, it is generally thought that the sight greatly influences the QOL (quality of life) of people. It is a vitreous body to take an important role to obtain visual information[3]. The vitreous body, which holds about 80% of the volume of the eyeball, is located between the crystalline lens, a ciliary body and the retinas and maintains transparency to send light stimulation to the retina[4,5]. In addition, the vitreous body supports neighboring eyes organizations and takes a role to protect naked eye tissue from external force, for example to prevent wound-related detached retinas by its high dynamic strength and excellent viscoelasticity[1,2]. However, the function of the vitreous body deteriorates with aging; shrinkage of vitreous body causes detached retinas and there is a threat that loss of eyesight is induced depending on a case[6,7]. Elucidation of the mechanism on vitreous body shrinkage with the aging is yearned to prevent detached retinas. A lot of researchers have extensively studied about the shrinkage of vitreous body. Paul et al. reported that the gel ratio of the vitreous body decreased with aging[8]. And, it was reported that the mechanisms of shrinkage of the vitreous body, which was composed of 3-dimensional network structure of collagen, hyaluronic acid and its derivative salts[9], were the main chain scission of hyaluronic acid or its derivative salts and resulting the liquefaction of the vitreous body[10-13]. On the other hand, Spoel reported that crosslinking of the collagen was a main cause of the shrinkage of the vitreous body[14,15]. The studies, such as above-mentioned, about the mechanisms of the shrinkage of vitreous body were performed on a premise that the accumulated reactive oxygen species (ROS) affected the shrinkage of the vitreous body by a depression of the antioxidant ability with the aging. The shrinkage of the vitreous body is influenced by not only such an internal factor but also external factors such as chemical additives in food, air pollution and the increasing ultraviolet (UV) irradiation caused by depletion SHRINKAGE OF VITREOUS BODY CAUSED BY HYDROXYL RADICAL