METHODS. Albino rats received b-alanine in the drinking water to induce taurine depletion. One month later, half of the animals were exposed to white light (3000 lux) continuously for 48 hours and the rest remained in normal environmental conditions. A control group of animals nontreated with b-alanine also was prepared, and half of them were exposed to light using the same protocol. All the animals were processed 2 months after the beginning of the experiment. Retinas were dissected as wholemounts and immunodetected with antibodies against Brn3a, melanopsin, S-opsin, and L-opsin to label different retinal populations: Brn3a þ retinal ganglion cells (RGCs) (image-forming RGCs), m þ RGCs (non-image-forming RGCs), and S-and L/M-cones, respectively. RESULTS. Light exposure did not affect the numbers of Brn3aþ RGCs or m þ RGCs but diminished the numbers of S-and L/M-cones and caused the appearance of rings devoid of cones, mainly in an ''arciform'' area in the superotemporal retina. Taurine depletion caused a diminution of all the studied populations, with m þ RGCs the most affected, followed by Scones. Light exposure under taurine depletion increased photoreceptor degeneration but did not seem to increase Brn3a þ RGCs or m þ RGCs loss. CONCLUSIONS.Our results document that taurine is necessary for cell survival in the rat retina and even more under light-induced photoreceptor degeneration. Thus, taurine supplementation may help to prevent retinal degenerations, especially those that commence with S-cone degeneration or in which light may be an etiologic factor, such as inherited retinal degenerations, AMD, or glaucoma.

Dystrophin contributes to force transmission and has a protein-scaffolding role for a variety of signaling complexes in skeletal muscle. In the present study, we tested the hypothesis that the muscle adaptive response following mechanical overloading (ML) would be decreased in MDX dystrophic muscle lacking dystrophin. We found that the gains in muscle maximal force production and fatigue resistance in response to ML were both reduced in MDX mice as compared to healthy mice. MDX muscle also exhibited decreased cellular and molecular muscle remodeling (hypertrophy and promotion of slower/oxidative fiber type) in response to ML, and altered intracellular signalings involved in muscle growth and maintenance (mTOR, myostatin, follistatin, AMPKα1, REDD1, atrogin-1, Bnip3). Moreover, dystrophin rescue via exon skipping restored the adaptive response to ML. Therefore our results demonstrate that the adaptive response in response to ML is impaired in dystrophic MDX muscle, most likely because of the dystrophin crucial role.