光动力疗法与热损伤对正常大鼠胃损伤的研究

为了初步探讨ＰＤＴ与热损伤对正常胃损伤作用机制的差异，本实验以血卟啉衍生物及氩离子泵染料激光器为光敏剂及光源，观察了大鼠胃壁在单纯氩离子激光照射和ＰＤＴ时，照射部位的温度及组织学在照射后７２小时和二周的改变。结果：氩离子激光照射组和ＰＤＴ组胃壁温度均高于对照组（Ｐ＜０．０１），但ＰＤＴ组温度均低于３７℃。氩离子激光照射后的胃壁组织在７２小时各层组织均明显出血，炎细胞浸润，组织凝固坏死。电镜下见胶原纤维肿胀，排列紊乱，甚至溶解吸收。二周后损伤部位以纤维瘢痕组织修复。ＰＤＴ组在７２小时胃壁组织也有充血和炎细胞浸润，但仅有轻度组织坏死，损伤深度未超过粘膜下层。电镜下见胶原纤维结构基本正常。二周后损伤部位以组织再生修复，未留瘢痕。结论：ＰＤＴ与氩离子激光组织损伤及修复方式不同，ＰＤＴ不损伤胃粘膜下胶原纤维。

A Comparison of Damages on the Normal Rat Gastric Wall Induced by Photodynamic Therapy and Thermal Injury

There have been many reports on photodynamic therapy(PDT) of gastrointestinal cancer, but little data on the response of normal tissues to PDT. In this study, the mechanisms of damage to gastric wall induced by PDT and thermal injury were examined. The temperature measured in the gastric wall surrounding the laser fiber tip during the thermal injury was much higher than during the PDT(P<0 01) The histological examination revealed that the healing of gastric mucosa was complete by regeneration at two weeks after PDT, but by fibrosis after thermal injury. The transmission electron microscopy showed that following PDT collagen fibrils maintained their structure and periodicity, but by thermal injury became markedly swollen and lost their periodicity structure after thermal injury. We would conclude that PDT is collagen sparing.