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S. D. Varma, K. R. Hegde, S. Kovtun; Antioxidant Effects of Caffeine. Prevention of Lens Damage and Cataract Formation. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3818. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Intraocular generation of reactive species of oxygen in the lens and aqueous and consequent physiological damage to the tissue has been shown to be involved in the genesis of cataracts in experimental animals as well as in humans. The present studies were undertaken to examine the feasibility of inhibiting this process by caffeine, an alkaloid present in many common beverages.
Oxyradical effects were studied in vitro as well as in vivo. In vitro studies were conducted by incubating mice lenses in medium exposed to UVA (365nm) in the presence of kynurenine with and without caffeine (5mM). The extent of lens damage was assessed by determining the ability of the tissue to conduct active transport of 86Rb+ and by measuring the levels of GSH and ATP. In vivo studies were conducted in rats by incorporating caffeine with galactose in the diet and determining the levels of GSH, ATP and hydration index of the lenses, combined with morphological studies.
Incubation of the lenses under UVA in the presence of kynurenine lead to substantial inhibition of active cation transport as well as decreases in the levels of GSH and ATP. These deleterious effects were significantly prevented by caffeine. Its protective effect in vivo using galactosemic animals was evident by its ability to prevent the early loss of GSH, the first index of oxidative damage in this animal model. Lens hydration and ATP were also better maintained. The anti-cataractogenic effects were also strongly apparent ophthalmoscopically, ascertained further morphologically.
Caffeine has hence been found to be effective in protecting the lens against in vitro damage by oxyradicals generated photochemically, as well as in vivo by its ability to modulate the cataractogenic process in galactose-fed animals. These effects of caffeine have not been reported before and are hence considered highly interesting in view of its relatively high content in widely consumed beverages. ESR findings combined with its ability to prevent GSH depletion suggest that these effects are attributable to its property of scavenging ROS. However, additional modes of its action and their pharmacological significance are under investigation.
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