Structural and Functional Reorganization of the Retina in an Experimental Simulation of Age-Related Macular Degeneration and the Melatonin Effect

Abstract

The aim of the study was to evaluate regularities of morphological and functional reorganization of the rabbit retina in the experimental simulation of age-related macular degeneration (AMD) and the use of melatonin.Material and methods. The study included 21 sexually mature male rabbits (42 eyes) weighed 2800– 3300 g, chinchilla breed. All the animals included in the study were divided into 3 groups: group 1 (experimental) (n=9), group 2 (control) included animals that were simulated AMD (n=9), and group 3 (intact) (n=3). Surgical interventions were performed in sterile conditions using an Opton operating microscope (Germany). Massage of the retina was performed under visual control through fixed caliber ports with a 25 G silicone-tip cannula at 10 and 2 hours in 4 mm from the limb, retreating from the optic nerve disk at a distance equal its one diameter, until the pigment epithelium was destroyed (dispersion). The size of the injury was 3 mm (RF Patent for the invention No. 2480844, 2011). Group 1 (experimental) was orally administered a suspended solution of the drug “Melaxen” (the active substance is melatonin), dosage 10 ml/kg daily once a day from 21.00 to 22.00 h for 3 months. Animals of group 2 did not receive treatment. Experimental animals were removed from the experiment on the 30th, 60th and 90th days. A histological and immunocytochemical study of the retina of experimental, control, and intact (without AMD simulation) animals was performed, including two-stage reactions to identify proteins p-53 and bcl-2.Results. Experimental histological studies allowed us to obtain a model of AMD, which corresponded to the morphological manifestations of the exudative form of chorioretinal dystrophy and destruction with a primary lesion of the choriocapillaris layer of the uveal tract. The use of melatonin for therapeutic purposes resulted in the resistant adaptation of pigment epithelium and retina gliocytes, reduction of pigment dystrophy and hemorrhage, destruction, reduction of apoptotic dominant and plexiform layers of the retina.