小鼠血小板早期光动力学损伤的定量超微结构研究

Early Photodynamic Changes of Mouse Platelets: A Quantitative Ultrastructural Study

正常小鼠静脉注射血卟啉衍生物后不同时间取血分离血小板,照射红光后不同时间离心固定作电镜观察、形态测定和体视学分析。发现照光后即刻各实验组血小板的平均面积、周长、短轴及长短轴比、单个血小板的平均表面积和体积都显著增大,提示血小板被激活。照光后8小时不少血小板已坏死,16小时后几乎全部坏死,说明血小板对PDT非常敏感,且可在无血管内皮细胞参与的情况下直接被破坏。

Normal mice received hematoporphyrin derivative (10 mg/kg I.V.) immediately, 24 or 48 hours prior to red light irradation. The blood was collected and the platelet-rich plasma was irradiated by red light (100 J/cm^2). The platelets were fixed immediately, 8 or 16 hours after irradiation and processed for electron microscopie ex- amination and stereological analysis. Immediately after irradiation most platelets were swollen and deformated, showing significant increased mean area, perimeter, short axis and long axis/short axis ratio, mean cell surface area and mean cell volume. 8 hours after irradiation many platelets were necrotized and the remaining consider- ably damaged. 16 hours after irradiation almost all platelets were necrotized. Our findings provided a clear evi- dence that platelets are highly sensitive to PDT action, can be rapidly and directly activated and injuried by PDT even in the absence of vascular endothelium. The results obviously indicate that platelets may play an important role in the initiation of early vascular damage and microcirculatory alteration induced by photodynamic therapy in vivo.