兔视网膜脉络膜经瞳孔温热疗法生物学效应初探

The biological effect of transpupillary thermotherapy on rabbit retina and choroid

目的:探讨经瞳孔温热疗法(TTT)对灰兔视网膜脉络膜的生物学效应,为临床合理应用提供参考依据。方法:使用半导体激光器对8只灰兔视网膜进行照射,光斑直径1.2mm,曝光时间1min,激光功率分别为150,200,250,300mW,分别于激光后1h及1mo行光、电镜观察。结果:150mW激光照射时,仅使视网膜色素上皮(RPE)轻度变化;200mW时除RPE变化外,脉络膜细胞变性,毛细血管内红细胞淤滞、变形;随能量加大(250mW),RPE受损加重,外层视网膜也同时受累,晚期视细胞层及外颗粒层消失;当激光能量达到300mW时,全层视网膜均受到损伤,并可引起脉络膜出血,甚至出现新生血管内皮细胞。结论:TTT对正常灰兔视网膜脉络膜的效应与激光能量成正比,RPE及邻近脉络膜是TTT的主要作用部位。

AIM： To observe the biological effect of transpupillary thermotherapy （TTT） on rabbit retina and choroid, and to provide reference theoretically for the parameter choice of TTT in clinical treatment. METHODS： ITr was performed on 16 eyes of 8 pigmented rabbits using the 810nm diode laser （IRIS Medical Oculight SLx） in different intensity （spot size： 1.2mm; duration： 60s; power： 150, 200, 250 and 300mW）. Observations were made by light microscope and transmission electron microscope to investigate the changes of figure and structure of retina and choroid at lh and lmo after TTT, RESULTS： Only mild changes of retinal pigment epithelium （RPE） were found with the lowest irradiance （150mW）o In addition, cellular denaturation and stasis of the red blood cells in choroids also occurred for 200mW laser. When the irradiance was 250mW, the damage of outer part of sensory retina could be observed in the acute stage, and at lmo after TTT, the rod/cone cell and the outer nuclear layer disappeared, and the fibrous proliferation could also be found in choroid. With the energy of laser increased to 300mW, the total retina was damaged, and haemorrhage of choroids happened, even worse neovascularized endothelium was detected in some areas of choroid. CONCLUSION： TTT has a biological effect on rabbits retina and choroid in a laser energy-dependent manner.. RPE and the choroid nearby are the main targets of TTT therapy. The appropriate parameter may be used successfully in treatment of choroidal neovascularization （CNV）, whereas excessive intensity of TTT may induce CVN, which should be avoided in the clinical therapy.