FIGURE 9.

Impaired phagosomal digestion in RPE and ectopic mitochondria in photoreceptors in light-exposed Park2-deficient mice. Park2^−/− mice together with Park2^+/+ littermate controls at 6 weeks of age were exposed to intermittent light at 10,000 lux for 20 min per exposure, two exposures with a 2-h interval of dark adaptation. The ultra-structure of RPE and photoreceptors were examined 24 h after light exposure. No overt abnormality in RPE ultra-structure was displayed by Park2^+/+ mice (a). In Park2^−/− RPE cells, undigested or partially digested phagosomes were readily detected (arrows in b–d). A large amount of mitochondria was also present in Park2^+/+ RPE cells (d). The ectopic mitochondria were also frequently detected in Park2^−/− photoreceptors (e and f).