Anti-oxidative vitamins prevent lipid-peroxidation and apoptosis in corneal endothelial cells

Abstract

To determine the effects of vitamin supplementation on the lipid-peroxidation-mediated toxicity of iron-ions on corneal endothelial cells (CECs) leading to apoptosis, murine CECs were maintained in tissue culture medium supplemented with increasing concentrations of free iron-ions, a treatment known to lead to increased lipid-peroxidation. The concentration of anti-oxidative vitamins (ascorbic acid, tocopherol and retinoic acid) in the cell supernatant and in the cells was determined by high-pressure liquid chromatography. Apoptosis was assessed by quantification of caspase-3-like activity and by using annexin-V/propidium iodide stains for flow cytometry. Lipid-peroxidation was measured by the malondialdehyde method. Supplementation with anti-oxidative vitamins was tested for the ability to counteract the induction of apoptosis. The production of nitric oxide was assessed spectrophotometrically and the expression levels of inducible and endothelial nitric oxide synthase were determined by Western blot. Increasing levels of free iron led to a rapid loss of anti-oxidative vitamins in the supernatant and in the CECs. This was correlated with rising levels of malondialdehyde and increased apoptosis. Supplementation with ascorbic acid or alpha-tocopherol alone did not prevent lipid-peroxidation in the cells. A combination of vitamins C and E (ascorbic acid, tocopherol) or solitary supplementation with vitamin A (retinoic acid) prevented lipid-peroxidation. We thus present a novel in vitro model for testing the direct influence of pro-oxidative species on CECs. We also show that supplementation with anti-oxidative vitamins to CECs significantly prevents the generation of free-radical-induced oxidative injury and apoptosis. These findings may have important implications for the storage of human corneae prior to transplantation and for the prolongation of corneal graft survival.

Protective Effect of a Synthetic Antioxidant “Acetyl Gallate Derivative” Against Dimethoate Induced DNA Damage and Oxidant/Antioxidant Status in Male Rats

“…Compounds showing antioxidant activity can reduce the main load of oxidative stress but when there is an imbalance between oxidizing and reducing equivalents where the former predominates, for example when the antioxidant is oxidized and thus converted into a prooxidant, the antioxidant cellular defenses cannot fully keep up with the oxidative stress and important cellular constituents are damaged [60]. In our model, the supplementation of the two tested antioxidants resulted in attenuation of oxidative stress and consequently reduction in DNA damage, especially with the SAC compound.…”

Protective Effects ofN-Acetylcysteine Amide (NACA) on Gentamicin-Induced Apoptosis in LLC-PK1 Cells

“…Induction of iNOS by p38 MAPK has been demonstrated previously, [16][17][18] and iNOS-derived NO is a key molecule in tubular epithelial apoptosis induced by different toxic agents. [19][20][21] One mechanism by which NO can induce apoptosis is through increased expression or translocation of the pro-apoptotic protein Bax from cytosol to mitochondria. 22,23 In agreement with this, we observed Gen-induced increased expression of the pro-apoptotic protein Bax and decreased expression of the anti-apoptotic protein Bcl-2.…”

Processing and Development of Frying Oil from Fruit of Some Varieties of Dwarf Coconut

“…Senyawa hasil oksidasi seperti peroksida, aldehid dan keton berbahaya terhadap kesehatan manusia. Akumulasi senyawa-senyawa tersebut dapat menginduksi terjadinya penuaan (apoptosis) sel endotelial pada kornea mata (Serbecic dan Beutelspacher, 2005). Cara yang dilakukan untuk menghindari dan menghambat oksidasi pada minyak, yaitu penambahan antioksidan.…”