308nm准分子激光照射兔耳最小红斑量

Determination of minimum erythema dose on rabbit ear irradiated by 308 nm excimer laser

目的:明确308 nm准分子激光照射兔耳最小红斑量(Minimum Erythema Dose,MED)。方法:应用308 nm准分子激光照射30只兔子左耳,分别给予单次单剂量150、300、450、600、900、1350mJ/cm^2,右侧作对照。计算30只兔耳激光照射24、48、72 h后的MED平均值,并观察96 h后组织病理和透射电子显微镜(transmission electron microscopy,TEM)下超微结构的改变。结果:经308 nm准分子激光照射后,24、48和72 h后MED平均值均为(300+55.39)mJ/cm^2,其中86.6%(24只兔)MED值为300 mJ/cm^2。照射96 h后MED区较未照射区的组织病理:表皮和真皮层增厚,真皮水肿、毛细血管扩张,血管周围大量炎症细胞浸润,可见红细胞外渗。TEM:MED区照射96 h后胶原纤维变性、排列紊乱,纤维细胞细胞器凝聚呈团块状变性;血管周围可见炎症细胞浸润,红细胞外渗;部分血管管腔狭窄,血管内皮细胞和周细胞细胞核形态异型。96 h后红斑逐渐消退,10~14天内消失,病理和TEM均未见大面积坏死。结论:308 nm准分子激光是一种高效稳定和安全的光源。

Objective：To determine the minimum erythema dose （ MED） on rabbit ear irradiated by 308 nm excimer laser. Methods：The left ears of 30 rabbits were irradiated with the 308 nm eximer laser and the right ears were taken as the negative controls. The irradiation doses of the eximer laser on the left ears were 150, 300, 450, 600, 900 and 1350 mJ/cm2 . Then the average MED after 24 h, 48 h and 72 h in 30 rabbitswas calculated, and the micro-structure was observed under transmission electron microscopy （ TEM） , at 96 h after irradiation. Results：The average MED after 24 h, 48 h and 72 h was 300±55.39 mJ/cm2. Compared with non-irradiated areas, the MED area after 96 h irradiation showed that the epidermis and dermis were thick,edema, and angiotelectasis. The blood vessels were infiltrated with lots of inflammatory cells. Under TEM, in the MED area irradiated after 96 h, there were degeneration and disorganization of collagen fibres, and fibrocyte organelle was coalesced presenting as crumby degeneration. Around blood vessels there was infiltration with inflammatory cells and erythrocyte exosmosis. Erythema gradually regressed in 96 h and disappeared in 10-14 days, without any large area of necrosis in pathology and TEM. Conclusion：308 nm eximer laser is highly stability and safety.