A Experimental Study Of Treatment Of Venous Malformation With Photodynamic Therapy Combined Hematoporphyrin Monomethyl Ether With Red Laser Light

Objective: Photodynamic therapy(PDT) combined semiconductor laser(wavelength: 630nm) with hematoporphyrin monomethyl ether(HMME)is utilized to initially investigate the effects and application parameters on venous malformation(VM) by animal model. Also, the feasibility of red laser light treatment on VM is to be studied, especially its future application value on nodular or thicken VM.Methods: 36 adult hens were randomly divided into 12 experiment groups. Another 12 adult hens were equally created as blank group and control groups(i.e., three doses of photosensitiser injected groups without laser and four kinds of laser irradiated groups without HMME).Experiment groups were injected HMME at 5,10,15mg/kg dose in turn and immediately irradiated by argon ion pumped dye laser or semiconductor laser. The energy density of the former is 60J/cm~2 or 120J/cm~2.The latter's is 120J/cm~2 or 240J/cm~2.All of power density are 200mW/cm~2.After intravenous administration of laying dose HMME , two circular irradiated area with 10mm-diameter in every hen comb were quickly irradiated by two kind of laser with laying energy density. So every experiment group was repeated by 6 times. Observation by unaided eyes in groups each of six animals were conducted on the combs acutely and 1day,3days,7days,14days and 28 days after exposure to the laser light,including information of the color change and surface condition of irradiated area. Then the irradiated combs tissue were excised and fixed in 10%formalin.After stained with HE's stain, the degree and depth of injury in the blocks were examined with light microscope.Results: Neither blank group nor control group had significant change on combs appearance and architecture. But the area of irradiated site in the experiment groups with HMME combined with semiconductor laser light of wavelength 630nm showed blanching. The major architecture changes include injury of red blood cell and vascular endothelial cell, vessel wall damage, decrease of blood vessel amount. Furthermore, the blanching effect of combs in the experiment group with HMME dose of 10mg/Kg and energy density of 120J/cm~2 has lasted for about 2 weeks less than those with HMME dose of 10mg/Kg and energy density of 240J/cm~2 lasting for about 3 to 4 weeks. Besides, the blanching of experiment groups with semiconductor laser light was longer than those with argon ion pumped dye laser. The injury depth of experiment groups with semiconductor laser light dose of either energy density of 120 J/cm~2 and HMME dose of 15mg/Kg or energy density of 240J/cm~2 and HMME dose of 10mg/Kg or 15mg/Kg were notable deeper than those with argon ion pumped dye laser. Accordingly, the optimal treatment parameter should be recommended as HMME dose of 10mg/kg and semiconductor laser light (wavelength: 630nm) with energy density between 120 J/cm~2 and 240 J/cm~2.Conclusions: Photodynamic therapy of semiconductor laser(wavelength:630nm)with HMME could attain a favorable blanching effect in irradiated combs, as well as exerting much longer-term blanching and deeper treatment depth than argon ion pumped dye laser. The degree and depth of injury could be controlled by selecting suitable treatment parameter. So, it is likely to realize a preferable therapeutic efficacy on nodular or thicken VM only if treatment parameter be strictly controlled to avoid injuring non-target tissue.