Abstract
Abstract: :
Purpose: To investigate the developmental pattern of the Rho GTPases Rac1, Cdc42, and RhoB in the rd/rd mice, considering their potential importance for neuronal differentiation and dendritic remodeling, as well as for apoptosis. Methods: Rd mice (C3H/HeJ) and wild–type (wt) mice (C57BL/6J) were sacrificed at postnatal days 5 (P5), P9, P11, P15, P21 and P60. Their eyes were enucleated and processed for Western blotting and immunofluorescence. Results: Western blotting showed that the antibodies against Rac1, RhoB, and Cdc42 recognized proteins around 21–25 kDa in the wt and rd mice retina. Rac1, Cdc42, and RhoB were present in neurons and glial cells in the wt and rd mice retina during postnatal development, and continued to be expressed in adult. Amacrine, horizontal and ganglion cells contained these Rho GTPases, as well as Müller glial cells in both strains. In addition, Rac1 and Cdc42 were clearly seen in photoreceptor outer segments of wt mice, whereas in the rd these proteins disappeared concomitantly with rods degeneration. Interestingly, Rac1 was intensively expressed by photoreceptors nuclei at P10 rd mice, but not in the wt mice. These labeled cells belong to apoptotic photoreceptors, as confirmed by using TUNEL technique. Conclusions: The developmental pattern of the studied Rho GTPases was very similar in both species. Rac1 was the only exception, suggesting a possible role for this GTPase during photoreceptor degeneration.
Keywords: retinal degenerations: cell biology • retinal development • photoreceptors