| Objective To study the protective function of hypoxic preconditioning in photic injury mice and investigate the possible mechanism of gene regulation. Methods 54 BALB/C mice were randomly divided into simple light-induced group(SL), hypoxic pretreatment group (HP) and control group (CON). 6h 12h 36h and 7d~th f our sub-groups were got from SL and HP group separately. The mice of SL and HP were continually exposed to light for 3 h, which built model of light-induced damage. Morphology and thickness difference of photoreceptor cells in different group was examined by light microscope. Different expreesion of c-fos and caspase-1 gene was examined by immunohistochemical method, t-check and linear correlation analysis were used to deal with the results. Results (1)The histopathologic findings showed that normal mice had clear layers of retinal structures and outer nuclear layers were neatly arranged and the dying was clear. The other layers had no obvious changes. Morphological changes in receptors gradually deteriorated under progressive light exposure. The main changes were as follows : the outer nuclear layer became thinner and sparser. The outer segments of the optic rod photoreceptors were in a disorganized pattern and vesiculated in different degree, while no significantly retinal changes in the hypoxic pretreatment group; (2)In the normal retina, c-fos was negative. A great quantity of positive numbers appeared in outer nuclear layer 6h after light exposure and the retinal light injury reached its peak. There was still positive expression 12h and 36h after light exposure, which decreased gradually. No expression was found 7d after light exposure. The same regularity appeared in HP group. There were no statistical significance (p>0.05) between the SL group and HP group;(3) In the normal retina, caspase-1 was negative. A few of positive cells appeared in outer segment 6h after light.exposure. The positive expression increased as... |
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