Stratmann U, Schaarschmidt K, Lehmann R R, Schürenberg M, Willital G H, Berens A
Institute of Anatomy, Faculty of Medicine, University of Münster, Germany.
J Anat. 1995 Dec;187 ( Pt 3)(Pt 3):661-70.
The oesophagus of 18 minipiglets was exposed to endoscopic intraluminal irradiation with a 1320 nm Nd:YAG laser (10 W, 20 s) via a radial applicator with strictly radially symmetric light distribution. Immediately and at 2, 3, 4 and 8 wk after irradiation, the oesophagus was perfusion-fixed and filled with contrast solution. Radiographs were taken for evaluation by microradiometry. The specimens were subsequently prepared for light and transmission electron microscopy. The immediate reaction to irradiation was a morphological gradient of damage extending from the centre of the laser exposure where there was cellular thermonecrosis in all layers of the wall and condensation of the extracellular matrix, to a peripheral zone (at a distance of up to 8 mm from the region where the laser was centred) which showed only minor tissue damage manifested by intracellular vacuolation. In this zone dilatation of most vascular lumina was prominent. In the period between 2 and 8 wk after irradiation all phases of wound healing were observed and resulted in occlusion of the lumen of the oesophagus by early scar tissue after an interval of more than 3 wk at the former centre of laser exposure. Peripherally, epithelial regeneration resulted in a new luminal lining. Both the process of epithelial regeneration and that of fibrous repair indicated a good reparative capacity of laser-irradiated oesophageal wall tissues resembling the phases of normal wound healing. The immediate laser interaction with tissue indicated that the noncellular matrix components of tissues are more resistant to the photothermal effect than the cellular components.
18只小型猪的食管通过具有严格径向对称光分布的径向施照器，接受波长1320 nm的Nd:YAG激光（10 W，20秒）的内镜腔内照射。照射后即刻以及在2、3、4和8周时，将食管进行灌注固定并注入造影剂。拍摄X光片，通过显微放射测量法进行评估。随后将标本制备用于光镜和透射电镜检查。照射后的即刻反应是损伤呈现形态学梯度，从激光照射中心向外延伸，在该中心处食管壁各层均出现细胞热坏死以及细胞外基质凝聚，直至外周区域（距激光中心区域最远达8 mm），该区域仅表现为轻微组织损伤，表现为细胞内空泡形成。在该区域，大多数血管腔明显扩张。在照射后2至8周期间，观察到了伤口愈合的各个阶段，在激光照射前的中心区域经过超过3周的间隔后，早期瘢痕组织导致食管腔闭塞。在外周，上皮再生形成了新的管腔内膜。上皮再生过程和纤维修复过程均表明，激光照射的食管壁组织具有良好的修复能力，类似于正常伤口愈合的阶段。激光与组织的即刻相互作用表明，组织的非细胞基质成分比细胞成分对光热效应更具抗性。
