Lenticular Oxygen Toxicity

Abstract

High oxygen load has a toxic effect on bovine lenses in organ culture. These effects appear to be cumulative: the higher the oxygen partial pressure and the greater the number of exposures, the more severe the changes observed in the lenses. Changes marking toxicity follow the route of oxygen diffusion into the lens, from the periphery to the center. Cautious interpretation of the results may indicate a role of oxygen (and/or its derivatives) in human cataract formation.

Age-Dependent Control of Lens Growth by Hypoxia

“…Several studies have shown that exposure of the lens to increased oxygen is associated with increased opacification of the lens nucleus or frank nuclear cataracts. 33,36,37,[53][54][55] Epidemiologic studies revealed that lens thickness is a significant risk factor in age-related cataract formation. 39,40 In these studies, individuals with smaller lenses at the time of examination were more likely to have cortical cataracts, whereas those with larger lenses more frequently had nuclear cataracts.…”

Role of Glutathione S-Transferases in Lens under Oxidative Stress

“…As is the case in other tissues, the high content of glutathione in the lens is believed to protect the thiols in structural proteins and enzymes and thus allow for proper biological function. [8][9][10][11] Aging lenses or lenses under oxidative stress exhibit an extensively consumed GSH pool. The lens depends on a balanced redox state to maintain transparency.…”

“…Exogenous sources include ultraviolet light, ionizing radiation, chemotherapeutics, and environmental toxins. [8][9][10][11][12] Of the exogenous sources, polycyclic aromatic hydrocarbons are an important risk factor for the cataract formation through lipid peroxidation generated from the redox-imbalance in the cell, namely, oxidative stress. Additionally, ROS also directly damage the antioxidant-system, indicating that such damage leads to a lens weakened in certain aspects of the innate protection against oxidative stress.…”

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Among these GSTs, the majority (GSTA, GSTM, GSTP, GSTT, GSTZ and GSTO) are located in the cytosolic fraction and GSTK is located in the mitochondrial fraction. Based on the amino acid sequences, cytosolic GSTs within α class exhibit a greater than 40% identity and those between classes share an identity of less than 25%.…”

Oxidative stress and antioxidant defense elements in the genesis of cataracts

“…Протеини сочива који чине највећи део његове солидне масе имају дуг животни век и током старења долази до њиховог оштећења под дејством светлости, тачније ултраљубичастих зрака (79,192).…”