| Purpose: To make the model of local RPE degeneration in rabbits through argon laser and observe the functional and morphological characteristic of retina before and after laser photocoagulation. After transplanted the primary RPE cells into model rabbits' subretinal space, we studied the changes of visual function through F-ERG, the objectival measure combined with the observation of histological changes to discuss the efficiency of RPE transplantation for preventing the injuries and prepare for the study of clinical application.Methods: (1)10 healthy pigmented rabbits were selected. 7 of them were treated with argon laser photocoagulation. F-ERG was monitored from pre-exposure to various time points post-exposured to analyse the changes of visual function. The rest 3 rabbits were treated by the same way to be observed the pathological changes in the retina in7days after laser by light microscope. According to the functional and histological changes, the proper time of RPE transplantation was decided.(2)15 healthy pigmented rabbits were selected. 5 of them were suppliers of RPE cells. The rest 10 rabbits which prepared for the model of local RPE degeneration were randomly divided into two groups: the control group and the treatment group. No treatment was given to the control group after laser exposure. For the treatment group, the primary RPE cells were transplanted into the rabbits' subretinal space in the paths of pars plana in 7 days after laser exposure. F-ERG was detected from pre-transplant to various time points post-transplant. We compared the data between two groups and analyse the changes of visual function. Eyeballs were extirpated to be observed the pathological changes in 3 weeks after transplantation by light microscope.Results: (1)The b wave amplitudes of dark adaptation ERG (rod response) reduced to the nadir on day1 after laser photocoagulation, and a little recovered on day3, then keep balance which still lower than normal level. The latency time has no significant difference. The amplitudes of a or b wave (maximal combined response) reduced to the nadir at 4 hours after laser photocoagulation, and a little recovered on day1. Then keep balance after 7 days. The latency time has no significant difference. The amplitudes of OPs wave (oscillatory potentials) reduced to the nadir on day1 after laser photocoagulation, then recovered gradually after 3 days, but still lower than normal level. Through the slices of the laser eyes, we can find the demolished RPE cells. The choroid and the inner retina were not affected.(2) The b wave amplitudes (rod response) of treatment group were significantly increased in 1 week after transplantation as well as the a or b wave amplitudes of maximal combined response. Then there is a little decreased, but still higher than that of the control guoup. The amplitudes of the two groups have significant difference. There is no obvious difference in latency time. The OPs wave amplitudes of oscillatory potentials were recovered close to the normal level in 1 week after transplantation. There is significant difference between two groups after 1～2 weeks, but no obvious difference after 3 weeks. Through the slices of the retina, we can find the transplanted RPE cells can survive and there is no inflammation and immunoreaction.Conclusion: Laser photocoagulation can help to make the model of local RPE degeneration by demolishing the RPE cells and photoreceptors. The proper time of transplantation for the animol model is 7days after laser. RPE transplantation can improve the visual function and resume the blood supply and nutrition of retina, which shows its positive actions for the retinal injuries.
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