510.6nm激光诱导兔在体血管平滑肌细胞凋亡的研究

目的　观察510-6 nm 波长激光对兔在体血管平滑肌细胞(SMC) 凋亡的诱导作用。方法　日本大耳白兔36 只,由股动脉导入柱状光纤至腹主动脉,对腹主动脉血管壁进行分段激光照射,功率密度分别为50 、100 、200 或300 m W/cm2 ,照射500 或1 000 s 。于照射后4 、8 、12 、24 或72 h 处死动物,取照射段腹主动脉,光镜观察SMC 形态改变,DNA 末端标记法确定细胞凋亡率。结果　兔腹主动脉经100 m W/cm2 及以上功率密度的激光照射后24 h,SMC 可出现变性、凋亡和坏死三种损伤性改变,而血管内皮细胞无明显变化。激光诱导下SMC 呈现典型的细胞凋亡形态特征:细胞明显固缩,细胞质着色加深,染色质固缩深染,并沿核膜着边排列。DNA 末端标记显示,SMC 凋亡与激光照射剂量有关。在100 m W/cm2 照射1000 s 和200 m W/cm2 照射500 s组( 能量密度均为100 J/cm2) ,细胞凋亡的发生率最高。结论　510 .6 nm 激光以能量密度100 J/cm2 照射,能使兔在体腹主动脉SMC 发生细胞凋亡,且发生率较高。

Apoptosis of Vascular Smooth Muscle Cells in Vivo Induced by 510.6 nm Laser Irradiation

Objective To investigate the effect of 510.6 nm laser irradiation on apoptosis of vascular smooth muscle cells(SMC). Methods Rabbit normal abdominal aorta was irradiated by 510.6 nm laser with the power densities of 50, 100, 200 or 300 mW/cm 2 and the energy densities of 50, 100, 150, 200 or 300 J/cm 2. The apoptosis of SMC was identified by morphologic observation and specific labeling of nuclear DNA fragment (TUNEL) technique. Results A typical appearance of apoptosis was found in the groups of the power densities of 100, 200 and 300 mW/cm 2 at 24 hours after irradiation. Apoptotic SMC showed that the cells and nuclei were condensed, and the fragmented chromatin was arranged against the nuclear membrane. The TUNEL results indicated that the incidence rate of apoptosis in the group of the energy density of 100 J/cm 2 was higher than that of other groups. Conclusions 510.6 nm laser irradiation with the energy density of 100 J/cm 2 may initiate apoptosis of SMC in vivo.