光动力作用对鸡冠皮肤微循环影响的研究

Photodynamic Effect on Chicken Comb Microcirculation

目的观察光动力作用对鸡冠皮肤微循环结构和血流的影响。方法以来亨鸡鸡冠为实验动物模型。静脉注射HpD10mg/kg后,以波长为532nm、功率密度为100mW/cm2的倍频半导体激光照射。分别于照光5min后即刻、照光10min后即刻、照光20min后即刻、照光20min后第1天、照光20min后第3天分别取6只鸡冠行肉眼、活体显微镜、激光多普勒血流图、光镜和电镜检查,观察鸡冠激光照射处皮肤微循环结构和血流状态的动态变化。结果在本实验条件下,光动力作用5min时,微循环结构无改变,血流量增至对照组的1·17倍(P<0·05);光动力作用10min时,内皮细胞及管腔内血细胞轻度损伤改变,管腔扩张,血流量明显增加,为对照组的1·70倍(P<0·05);光动力作用20min时,微血管损伤明显,血流明显减慢,血流量为对照组的94·3%(P>0·05);光动力作用后第1天和第3天,微血管损伤加重,血流基本停滞,血流量分别为对照组的19·3%和21·6%(P<0·05)。结论光动力作用可造成鸡冠真皮乳头层毛细血管网损伤,初期微血管轻度扩张,血流加速,之后微血管损伤加重,血流紊乱。

Objective To gain an understanding of the changes in the microcirculation during and after photodynamic therapy （PDT）, compare the effect on different microvasculature and assess the relationship between the dose of photosensitizer and the injury of microcirculation. Methods The Lengon chicken comb microcirculation model was established for studying microvascular effect of photodynamic therapy in vivo. Animals were irradiated by 532 nm laser with power densities of 100 mW/cm^2 for 20 min after they were injected with HpD 10 mg/kg iv. The gross observation, light microscopy, electron transmission microscopy, intravital microscopy and laser Doppler flowmetry were conducted on the combs at time of 5 rain, 10 min, 20 min and d 1 ,d 3 after irradiation. Results In this test, the capillaries were dilatated in the initial stage of PDT, and the blood perfusion increased. While after longer PDT, the endothelial ceils （EC） of capillary net were phototoxic necrosis, walls of capillary net were destroyed and the microvasculature was decreased dramatically. The degree of this selective photosensitive destruction was positively related to doses of laser irradiations. The blood perfusion values at the time of 5 min, 10 min, 20 min and d 1 ,d 3 after irradiation were 1.17, 1.69, 0. 93, 0. 19 and 0. 22 times of that before PDT. Conclusions The characteristics of photodynamic effect on chickens comb microcirculation are slight reaction and blood flow speed up at first and then drop down quickly.