[The protective effect of hypoxic preconditioning against light-induced photoreceptor degeneration in mice]

To study the protective roles of hypoxic preconditioning in light induced retinal injury in a mice model and investigate the possible mechanism of related gene regulation.

54 BALB/c mice were randomly divided into simple light exposure group (SL), hypoxic pretreatment group (HP) and control group (CON). The mice of SL and HP were continually exposed to light for 3 h, which built model of light-induced damage. Morphologic changes of photoreceptor cells in different group were examined by light microscope and the apoptosis was detected by TdT-mediated dUTP nick end labeling. Different expressions of c-fos and caspase-1 gene were examined by immunohistochemical staining.

In group SL, the photic injury appeared very obviously and early. Different changes appeared in the outer nuclear layer after light exposure. Photic injury was aggravated following the increased light exposure. Positive staining of c-fos and caspase-1 could be seen in the outer nuclear layer. In group HP, the changes of retinal morphology appeared slightly and lately. Compared with group SL, caspsae-1 expression was decreased obviously, while no difference was seen in the expression of c-fos. The retinal structures was normal in the mice of control group and c-fos and caspase-1 were stained negative.

Hypoxic preconditioning has neuroprotective effect on photoreceptor cells by inhibiting the expression of apoptosis-related genes in photic injured mice model. caspase-1 may be involved in the protective mechanism.