Chronic Alcohol Feeding Increases the Size of the Choroidal Neovascular Complex in Rats

Abstract

Abstract: : Purpose: To investigate whether chronic and heavy alcohol consumption influences the pathology of choroidal neovascularization (CNV). Methods:Male Brown Norway rats (4–6 weeks old) were divided into two groups. Control group (gp1) was fed regular diet and water. Alcohol fed (gp 2) received 8 g/kg alcohol and a regular diet. The animals in both groups were sacrificed after 10 weeks. The eyes were enucleated to separate choroids. Choroidal homogenate was used to perform enzyme assay for rates of fatty acid ethyl ester synthesis. Also Paraffin embedded sections of the alcohol fed and control rat eyes were used for immunostaining for FAEES with rabbit anti–rat FAEES. Experimental CNV was induced on day 60 of feeding by laser photocoagulation (using the krypton red laser) in both groups. Three laser spots were placed in each eye. The animals were sacrificed on day 70, their eyes enucleated and RPE–choroidal –scleral flat mounts were stained with an anti–elastin (CY3 conjugated) antibody. The incidence and size of the CNV was determined by confocal microcopy. The CNV complex size was measured (µ) using Image Pro–Plus software. FAEES was purified from rat choroids. Western blot analysis was done for the expression of cyclin E and cyclin E/CDK 2 proteins. Results: A 4.0 fold increase in FAEES activity was observed in the choroid of alcohol fed rats compared to controls. However, no significant increase in FAEES activity was observed in the cornea, iris & ciliary body, lens and retina. Histoligic sections of the eye of alcohol fed rat showed increased staining for FAEES compared to control rats, which showed only a very light stain for FAEES. There was a 28 % increase in the CNV complex size (n=80 laser spots/group) in alcohol fed rats compared to control rats. The incidence of CNV in each group was 92%. We also observed three fold increase in the expression cyclin E and cyclin E/CDK 2 in the choroid of alcohol fed rats compared to control rats. Conclusions: Our results suggest that heavy and chronic alcohol feeding enhances the CNV complex size by increasing the expression of cell cycle proteins. Thus, we suggest that heavy and chronic alcohol use may enhance the progression of vision loss in ARMD patients.

Keywords: age-related macular degeneration • choroid: neovascularization • inflammation