AIM: To study the expression of Bcl-2/Bax in contusion of the rat retina and the effect of N-acetyl-cysteine(NAC)on it.

METHODS: The animal model of retinal injury was created by a free falling iron bar hitting the rat cornea. The rats were divided into normal group(n=6), contusion group(n=24)and treatment groups of NAC(n=24)randomly. After retina contusion, the latter two groups were subdivided into 1 day, 3 days, 7 days and 14 days group; there were 6 rats in each observation period. Structural changes of retina were observed with light microscope, and the expression of Bcl-2/Bax was observed by immunohistochemistry.

RESULTS: In the contusion of the rat retina, retinal damage was concentrated in sensory layer. RGC layer, inner nuclear layer, and outer nuclear layer cells were obviously observed. After contusion, retinal tissue edema, cell disorder, cytoplasm vacuolated changes, thinning of retinal tissue, and cell loss were began to appear. No expression of Bax was found in normal group and treatment group, and low expression of Bcl-2 was observed. Most of Bax positive cells had expression at 1 day after contusion injury in contusion group, and then increased obviously at 3 days, and decreased at 7 days and much further at 14 days, and Bcl-2 positive cells had expression at a low stage. Treatment group had the same trend with the contusion groups in each index, but the expressive intensity of each period weakened in evidence. There were significant differences between two groups at 1 day,3 days and 7 days after contusion(P<0.05). The expression of Bcl-2 in each period of time was increased. Compared the two groups with 1 day, 3 days after contusion and 7 days had a significant difference(P<0.01 ).

CONCLUSION:In the contusion of the rat retina, NAC can improve the retina damage, and may protect the retinal tissue from contusion injury by regulating Bcl-2/Bax protein expression.