Abstract
Abstract: :
Purpose: To study the choroid and retina wound healing events in the mouse eye. Methods: Wild type C57BL mice, six to eight weeks old underwent krypton laser photocoagulation: After pupil dilatation and ketamine anesthesia, krypton laser fundal lesions were created. The three essential parameters of the photocoagulation burns were varied as follows: Group I, treatment consisted of the "classic protocol", 50um spot size, 0.05''duration and 400mW power.For Group II, the power and duration were similar to Group I (400mW and 0.05") and the spot sizes 50, 100 and 200um. For Group III, the power and spot sizes were similar to Group II (400mW and 50,100 and 200um) and the burn duration was 0.1". For Group IV, the spot size and the duration remained constant (100um and 0.1") and the power 100, 200 and 300mW. Forty mice (80 eyes) received one single lesion located one to two disc diameters nasal to the optic nerve in both eyes. Ten mice (one of Group I and three from each of the Groups II,III,and IV) were sacrificed 24 hours, 3,7, 14 and 30 days after photocoagulation. One eye of each mouse was snap frozen, cryopreserved in OCT and processed for immunohistochemical analysis using specific antibodies directed against GFAP, CD4, Lectin and von-Willibrand factor receptors.The second eye was preserved in 4% PAF and processed for conventional histology. Analysis of the staining patterns and cellular composition changes within the laser lesion and its vicinity were carried out. Results: The retinal nuclear cell layers, glial cells and retinal blood vessels participated actively in the wound healing processes when the photocoagulation affected the integrity of the choroid.The retinal nuclear cell layers underwent anatomy "remodulation and adaptation" and the retinal vessels appeared to follow these changes with excessive engorgement and elongation of the capillaries. Their normal anatomy relations however were kept at all times.The GFAP positive cells of the retina on the other hand undergo rapid stimulation, elongate and fill the void within the choroid. The contribution of the choroid to the wound healing activity appeared to be localized mainly on the immediate vicinity of the laser lesion. Conclusions: In this model, wound healing processes of the chorio-retinal complex appear to be mostly driven by the retinal cells which undergo remodelling (nuclear layers and vessels) and proliferation (GFAP positive cells).
Keywords: retina • wound healing • animal model