Delay of Cataract Development in the Shumiya Cataract Rat by the Administration of Drinking Water Containing High Concentration of Magnesium Ion

Abstract

Mineral ion, an essential element, plays a very important biochemical role in the body. It has been recognized that mineral ion imbalance is associated with several major diseases, such as diabetes mellitus, hypertension, cardiovascular and cerebrovascular diseases and heart infarction. [1][2][3][4][5][6][7] In addition, Iwata and Kinoshita reported mineral ion imbalance in the lens causes cataract. 8,9) Any alteration in the optical homogeneity of the lens or decrease in its transparency is known as a cataract, 10,11) and numerous factors have been implicated in its etiology. These involve genetic factors, diabetes, smoking, nutrition, the cumulative effect of X-rays, ultraviolet irradiation, and alteration in both endocrine and enzymatic equilibrium. [12][13][14][15][16][17] Cataractous lenses have been found to have an altered distribution of the intracellular ionic environment. The concentration of calcium ion (Ca 2ϩ ) was increased in many cataractous lenses. There have been many reports on the relationship between Mg 2ϩ and cataract. The Mg 2ϩ in the lens increased in diabetic 14) and ultraviolet-irradiated rats. 18) On the other hand, lipid peroxides 19) and cigarette smoke 17) reduced the Mg 2ϩ in the lens. In human senile cataract, Dilsiz et al. reported that lens ionic imbalance with increased levels of calcium and sodium, coupled with decreased levels of magnesium and potassium, is related to cataract development. 20)These lens ionic imbalances arise as a result of changes to lens membrane characteristics causing an increase in lens membrane permeability.Over the past several decades, there have been many studies exploring the mechanisms of cataract development. 21)Currently, reactive oxygen species (ROS), induced by UV rays in sunlight, are considered to be important in perturbing lens homeostasis. Therefore, exposure to ROS results in a breakdown of lens homeostasis, and the Ca 2ϩ concentration in the lens becomes elevated. The elevated Ca 2ϩ concentration in the lens has been induced to activate calpain, a Ca 2ϩ -dependent protease. Furthermore, the degradation of lens proteins such as crystallin proteins would result in an opaque lens. 20,22) This ROS is enhanced by hyperglycemia and Mg deficiency. 23)The Shumiya cataract rat (SCR), which was established by Shumiya and Nagase, is a hereditary cataractous rat strain. 24)Lens opacity in SCR appears spontaneously in the perinuclear and nuclear portions at 11-12 weeks of age, and cataract appearance in adult SCR was 66.7%.25) Previous investigations have revealed that oxidized glutathione concentrations in the SCR lens are increased, and reduced glutathione values are decreased.26) The proteolysis of some crystallins and cytoskeletal proteins was significantly enhanced in cataractous SCR lenses. The calcium concentrations in cataractous lenses rise markedly with age compared with non-cataractous lenses, and the autolytic product of calpain is also detected in cataractous lenses.27) It is noteworthy that SCR cataracts are not diabetic cataracts. T...

Effect of Magnesium Deficiency on Intracellular ATP Levels in Human Lens Epithelial Cells

“…[18][19][20][21][22][23] Recently, we reported that appropriate supplementation of Mg 2ϩ suppressed the decrease of Mg 2ϩ concentration and the increase of Ca 2ϩ concentration in SCR rat lenses, resulting in delayed cataract development. 24) These findings suggest that the Mg 2ϩ concentration in the lens relates to the progression of lens opacification. In this study, we investigated the effect of Mg 2ϩ deficiency on NO production, the ATP level and ATPase activity in HLE cells.…”

Taurine Prevents Oxidative Damage of High Glucose-Induced Cataractogenesis in Isolated Rat Lenses

“…Photographs of the lens were taken using a dark-field set up with illumination from a circular light situated above the lens by microscope equipped with a CCD camera (Olympus, Japan). The outline of the lens image was determined by selecting 4 points on the image, and then the transparent area within the outline and thread level were set automatically by the software ( 21 ). The total area of opacity, in pixels, was analyzed by a computer using Image Pro Plus system (Media Cybernetics, USA).…”

Cardiovascular protection of deep-seawater drinking water in high-fat/cholesterol fed hamsters

“…The biological functions of DSW have been investigated for various uses, including attenuating hyperlipidaemia, as well as atherosclerosis, dermatitis syndrome and allergic skin responses (Hataguchi, Tai, Nakajima, & Kimata, 2005;Kimata, Tai, & Nakajima, 2001;Miyamura et al, 2004;Ueshima, Fukao, Okada, & Matsuo, 2003;Yoshioka et al, 2003). Nagai et al (2006) indicated that intake of Mg from DSW delays cataract development in the shumiya cataract rat. Ouchi et al (1990) indicated that dietary Mg prevents atherosclerosis in rabbits fed a cholesterol-enriched (1%) diet.…”