FIGURE 8.

Enhanced expression of Park2 is associated with light-induced retinopathy and Park2 deficiency results in light-induced retinopathy. A, Park2 expression in the retina of albino WT mice at 6 weeks of age was examined by immunohistochemistry, revealing that Park2 is ubiquitously expressed in the retina. Bars indicate 20 μm. B, Abca4^−/−Rdh8^−/− mice at 6 weeks of age were exposed to white light at 10,000 lux for 30 min. Park2 expression in the retina was then examined by SDS-PAGE followed by Western blotting with triplicate samples. Up-regulated Park2 expression was observed in response to light exposure. Compared with no light. *, p < 0.01; #, p < 0.05. Is, inner segment; OPL, outer plexiform layer; INL, inner nuclear layer; GC, ganglion cell; OS, outer segment. C, Park2^−/− mice together with Park2^+/+ littermate controls were exposed to intermittent white light for 40 min given by 20 min each with a 2-h dark adaption between each illumination. Histological examination on plastic sections after toluidine blue staining revealed the photoreceptor damage in Park2^−/− mice compared with the intact photoreceptor structure in Park2^+/+ mice. Bars indicate 20 μm. D, the ONL thickness was measured by SD-OCT and plotted (*, p < 0.01; #, p < 0.05).