Abstract
Abstract: :
Purpose:Our aim was to induce photochemical injury in RPE cells in murine high fat diet model resulting in the formation of basal linear (BlinD) and basal laminar (BlamD) like deposits and to examine the carbohydrates composition of the basal deposits in our murine model. Methods:C57BL/6 mice (n=15) 8 weeks old were fed high fat rodent diet for three months. The right eye was then exposed to blue light from an Argon laser source for 7 seconds every other day over 2 weeks at a wavelength of 488 nm and energy of 20mJ. One month after treatment, the mice were sacrificed and their eyes were enucleated. A piece from the posterior pole, 1 mm away from the optic nerve, measuring 2x2 mm in the area of laser exposure was harvested for transmission electron microscopy (TEM) and immunostaining with biotinylated lectins that binds to carbohydrates moieties(soybean agglutinin (SBA), Dolichos Bifloris (DBA) and wheat germ agglutinin (WG), commercially available lectins, Vector labs, CA). A control group consisted of the same number of mice at the same age, which were fed a normal rodent diet for the same time and then subjected to the same treatment as the high fat diet group. Results: 10/15 mice in the high fat diet group survived the experiment. Sections from 9 mice were sent for TEM. 7/9 lasered eyes developed BlamD on TEM; whereas, 4/9 control eyes developed BlamD to a much lower extent. WG staining was positive in 4/8 eyes of the high fat diet group. None of the controls had detectable BlamD by immunostaining. SBA and DBA were negative in both groups. Conclusion:Laser and high fat diet enhance the development of basal deposits in murine model. Murine basal deposits contain sialic acid (N-acetyl Neuraminic acid), the carbohydrate moiety detected by WG agglutinin. It does not contain N-acetyl galactose-amine detected by SBA and DBA. This carbohydate moiety was found in the human macular basal deposits. However, mice do not have a macula and this could explain the absence of both lectins in mice basal deposits.
Keywords: 506 pathology: experimental • 308 age-related macular degeneration • 421 glycoconjugates/glycoproteins