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S. Kaliappan, P. Jha, V. V. Lyzogubov, R. G. Tytarenko, N. S. Bora, P. S. Bora; Increased Severity of Choroidal Neovascularization in Laser Treated Rats After Alcohol and Nicotine Feeding. Invest. Ophthalmol. Vis. Sci. 2008;49(13):5171.
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To investigate the effect of alcohol and nicotine consumption on the pathology of choroidal neovascularization (CNV) in rats after laser-photocoagulation.
Male Brown Norway rats were divided into five groups. The animals in all five groups received the regular diet and CNV was induced by laser photocoagulation. After laser, group I received alcohol (8 g/Kg body weight), group II received nicotine (200µg/ml) and group III was fed with a combination of alcohol and nicotine. The group IV and V were fed with water and glucose which served as the control and pair-fed control respectively. CNV was determined by confocal microcopy and the size of the complex was measured using Image Pro software. VEGF and MAC deposition was detected by immunofluorescent staining of paraffin sections. Another set of animals which did not receive laser treatment were sacrificed after four weeks of alcohol and nicotine feeding. The choroid and serum samples from these animals were collected and mRNA and protein levels of CD59 were detected using RT-PCR and Western blot analysis. The levels of VEGF were detected by RT-PCR. Total hemolytic complement activity was also detected in these samples.
Confocal microscopic analysis showed a 3.4 fold increase in CNV complex size in alcohol fed rats compared to water fed and pair-fed controls. Our results further demonstrated that there was a 2 fold increase in CNV complex size in rats treated with nicotine as compared to the control group while the combination of alcohol and nicotine treatment resulted in 3.5 fold increase in CNV size. Immunohistochemical analysis of paraffin sections of choroid demonstrated increased presence of MAC and VEGF in lasered animals that were fed with alcohol, nicotine or combination of both. There was no significant difference in total serum hemolytic activity between the animals that received the alcohol or nicotine treatment but no laser treatment. However, the levels of CD59 were dramatically reduced in the choroid of alcohol and nicotine fed animals compared to water fed controls. Interestingly, VEGF mRNA was also up-regulated in these samples.
Our results demonstrated that the alcohol and nicotine treatment reduced the levels of CD59 that resulted in increased MAC deposition. Increased MAC deposition in turn leads to increase in VEGF release and thus higher severity of CNV. These results implicate that increased complement activation due to loss of regulation may be a possible mechanism responsible for the association between alcohol and nicotine consumption and higher risk for AMD.
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