Abstract
Abstract: :
Purpose: To study the functional correlation between light responses and cell signatures in the rd1 mouse retina. Structural changes that affect horizontal cells, bipolar cells, Müller cells and rod photoreceptors were studied during the process of rod degeneration in the rd1 mouse model of retinal degeneration. Methods: Full field electroretinographic responses were recorded from the rd1 mouse retina at different postnatal days (p11, p14, p18 and p24). Immunocytochemical labeling of specific cell types of the rd1 mouse retina was performed at 11, 14, 18 and 24 postnatal days. Antibodies against the rod photoreceptors (anti-rodopsin), bipolar cells (anti-αPKC), horizontal cells (anti-calbindin), Müller cells (anti-glutamin synthetase, GS) were used. NMRI mouse retina was studied for control experiments. Results: Electroretinographic responses were observed in the rd1 mouse at eye-opening. Light responses decreased with time and a complete absence of light responses were observed by p24. Rod labeling in the rd1 mouse matched the functional recordings: the number of cell somas of rod photoreceptors did not show differences to control animals at p11; they decrease to 20% by p18 and were practically absent by p24. Immunocytochemical labeling of the mouse retina with anti-αPKC and anti-calbindin confirmed the profound morphological changes observed in bipolar and horizontal cells of the rd1 mouse (Strettoi et al, J.Neurosci. 22:5492, 2002). Positive immunocytochemical labeling of retinal Müller was observed by p11 in control animals, and was complete by p18. In the rd1 mouse retina, labeling of Müller cells showed no differences to control animals by eye opening; at p24, when no rods were present, no significant changes were observed in Müller cells; integrity of the external limiting layer was observed in absence of rod photoreceptors. Conclusions: Structural modifications in the rd1 mouse retina matched changes in the electroretinographic responses after eye opening (p11-p24) and affect mainly to rod photoreceptors and their postsynaptic cells, but not the Müller that surround the degenerated cells.
Keywords: retinal degenerations: cell biology • retina: distal(photoreceptors, horizontal cell • degenerations/dystrophies