AIM: To investigate the effects of different forms of light on the expression of TGF-β₂ of guinea pig retinal pigment epithelial(RPE)cells.

METHODS: Ten two weeks old healthy guinea pigs, RPE cells were cultured conventionally and divided into four groups: focused light group, defocused light group, parallel light group and the control group. The first three groups were exposed to the focused light, defocused light(passed though lens from parallel light)and the parallel light, the control group was untreated. The level of the expression of TGF-β₂ protein and TGF-β₂mRNA was measured by immunocytochemistry and real-time fluorescence quantitative chain reaction 24 hours after light exposure and the pattern-effect relations were explored. The data were analyzed by means of analysis of variance(ANOVA).

RESULTS: The level of both TGF-β₂ protein and TGF-β₂ mRNA were significantly increased in the focused light exposed group compared with the other groups, followed with the defocused group(P<0.05).

CONCLUSION: It was suggested that different forms of light can affect the expression of TGF-β₂ in guinea pig RPE cells, and was most obvious in the focused light exposed group.