Obeservation Of Choriocapillaris Closure From Domestic Photosensitizer Photodynamic Therapy

Objective:1 To observe the biological effect and to calculate the retinal damage threshold by 532nm consecutive wavelength to investigate whether 532nm wavelength laser can be used safely as light source during PDT.2 To observe the choriocapillaris closure during hematoporphyrin mono methyl ether(HMME) photodynamic therapy(PDT) in New Zealand rabbits in order to investigate whether HMME-PDT can be used to treat aging macular degeneration(AMD). To observe the retinal and choroidal photodynamic effect on the irradiated area during HMME-PDT with different light energy at different irradiation opportunity and dye dose. And to observe the retinal recovery and persistence of choriocapillaris occlusion at long-term follow-up.3 To observe the biological effect of hypocrellin B (HB) photodynamic therapy(PDT) on the normal retina and choroid of the rabbits in order to investigate whether HB-PDT can lead to the selective occlusion of choriocapillaris.Method:1 The fundi of the New Zealand's rabbits were irradiated by 532nm consecutive laser, the irradiation of the size were 1.5~2.5mm, the power density was 500~2400mW/ cm2 and the duration of irradiation 100~300s. Fundus photograph and fluorescein angiogaphy were performed 1 hour and 24 hour after the irradiation to determine the retinal damage threshold and the characteristics of the retinal damage at different level of irradiance.2 â‘  The normal choriocapillaris of the New Zealand rabbit was used to test photodynamic effect by HMME, which dose was HMME 5mg/kg body weight and was activated by 532nm laser with fluence of 20, 30, 45 and 60 J/cm within 10 seconds after intravenous injection of HMME. (2) Following intravenous injection of HMME 5mg/kg, the fundus was irradiated 10 seconds, 5, 10 and 15 minutes respectively after photosensitizer injection with an irradiance of 20, 30 and 40J/cm2 respectively. (3) The fundi were irradiated with a energy fluence of 20, 30 and 45 J/cm within 5 minutes after the drug injection of 2.5, 5 and 10 mg/kg. The treated area were imaged at 1 and 7 day after PDT in each above experiment. â‘£ Photodynamic therapy was performed with an irradiance of 400mW/cm and fluence of 40 J/cm . Follow-up studies were designed at 1, 2, 4, 6 and 8 week after PDT.3 HB, the dosage 0.5mg/kg, was activated by 532nm laser with different PDT parameter. At the 1, 7, 14 and 28 day after PDT, the fundus photograph, fluorescein angiography and histological examination were performed to test the biological effect on the irradiated area.