光动力疗法与Nd：YAG激光对胃胶原纤维损伤机制的比较

光动力疗法对于胃肠道肿瘤治疗效果令人鼓舞。但有关ＰＤＴ对胃肠道正常组织损伤的研究甚少。探讨了ＰＤＴ与Ｎｄ：ＹＡＧ激光对胃组织损伤的差异。结构发现：Ｎｄ：ＹＡＧ激光治疗过程中光纤周围组织温度明显高于ＰＤＴ组。光镜下二者均可造成明显组织损伤，但二周后修复方式不同，Ｎｄ：ＹＡＧ激光以纤维疤痕组织修复，而ＰＤＴ以正常组织再生修复，电镜发现Ｎｄ：ＹＡＧ激光致胃粘膜下胶原纤维明显损伤。

Contrasting Mechanisms of Gastric Collagen Damage Induced by Photodynamic Therapy and Nd:YAG Laser

Photodynamic therapy(PDT) has promising potential for the treatment of gastrotestinal cancer.However, there is a little data on the response of normal gastrointine to PDT. In this sudy, the differing mechanisms of damage to gastric wall induced by Nd YAG Laser and PDT were examined.The temperature measured in the gastric wall surrounding the laser fiber tip during the Nd:YAG laser treatment was much higher than during the PDT(P<0.01).The histological changes induced by PDT and Nd:YAG laser were seen.Healing by regeneration was complete by two weeks of PDT, and by fibrosis after Nd:YAG laser treatment.Using transmission electron microscopy we examined collagenn from normal gastric wall and gastric wall damged by PDT and Nd: YAG laser. Following PDT collagen maintained its architecture and Petidicity. Damaged Collsgen by Nd: YAG laser became grossly swollen and lost its fibrillary architectrure.It is concluded that PDT shows no harmful effect on collagen.