竹红菌乙素-光动力学疗法治疗脉络膜新生血管方案的初步探讨

Effect of Photodynamic Therapy Using Hypocrellin B on Choriocapillaris in Rabbits:An Experimental Study

目的观察不同参数的竹红菌乙素-光动力学疗法(HB-PDT)对青紫蓝兔脉络膜毛细血管层的生物学效应以及对视网膜的非选择性损伤,为临床应用HB-PDT疗法治疗脉络膜新生血管(CNV)提供依据。方法青紫蓝兔18只,随机分为6组,每组3只。其中药物对照组耳缘静脉注射HB1.5mg/kg,不照激光。激光对照组耳缘静脉注入生理盐水2.0mg/kg,PDTⅠ-Ⅳ组耳缘静脉注射HB各1.0mg/kg,分别以能量密度为240、14.4、30.0、48.0和56.0J/cm2,波长为532nm的倍频YAG激光照射兔眼底。观察兔眼底变化、荧光素渗漏情况及视网膜、RPE、视细胞、脉络膜的组织病理学变化。结果在PDT后第1天,单纯照光组和单纯药物对照组眼底和组织学无改变;HB剂量为1.0mg/kg,功率密度120～700mW/cm2、能量密度14.4～56.0J/cm2的532nm激光照射,可以导致脉络膜毛细血管层的闭塞,视网膜外层损伤,内层无明显改变。HB剂量1.0mg/kg,功率密度300～600mW/cm2,照光时间80～100s,能量密度30～50J/cm2是适宜的治疗参数。结论HB对视网膜和脉络膜的生物学效应与光敏剂的剂量和激光照光时间、功率密度、能量密度密切相关。生物学效应与能量密度呈量效依赖性关系。

Objective To compare the biological effects of different treating parameters of HB-PDT on choroid and retina and to supply the basic study of HB-PDT in treating choroidal neovascularization (CNV). Methods The 532 nm laser and split microscope as the irradiation system were used.Chichilan rabbits weighing from 2.5 to 3.5 kilogram were used as the experimental animals. After rabbit was anesthetized and the pupil was dilated,the rabbit′s fundus was irradiated with different treating parameters.Three cases were in every group.The fundus photography,fluorescein angiography and histological examination were performed at the first after PDT.The samples of light only control group and photosensitizer only control group were dealt with by the same method. Results There was no structural change in light only and the photosensitizer only control groups.The closure of choriocapillaris was seen at drug dose 1.0 mg/kg,power density 300-600 mW/cm2 and energy fluence 14.4-56.0 J/cm2. Conclusions The biological effect is determined by dose of sensitizer,interval between injection of photosensitizer and irradiation,power density and energy fluence.The higher the dosage of the photosensitizer is and the stronger the energy fluence is,the greater the choroidal biological effect is and the more serious the retinal damage is.