高能电子线皮肤辐射损伤动物模型的超微病理学研究

目的 通过动物模型研究高能电子线皮肤辐射损伤产生延迟性坏死和溃疡难以愈合的病理改变和机理，为进一步临床研究打下基础。方法 本实验以ＳＤ大鼠作为实验对象，以直线加速器产生的４ＭｅＶ的电子线照射臀部皮肤制作皮肤放射损伤模型。实验动物分５Ｇｙ、１５Ｇｙ、３０Ｇｙ、４５Ｇｙ４个剂量组，一次性照射后２个月作病理学肉眼、光镜、电镜观察。结果 ５Ｇｙ组光镜形态改变不明显，电镜下可见棘细胞肿胀，基底细胞核固缩，核膜下染色质边集，血管内皮细胞肿胀，部分细胞核固缩，管腔狭小，皮下胶原纤维断裂水肿：１５Ｇ６ｙ组棘细胞和基底细胞肿胀明显，基底细胞胞浆内张力微丝、桥粒、半桥粒显著减少，血管内皮和毛囊上皮细胞变性；３０Ｇｙ组电镜下棘细胞、基底细胞核固缩、水肿明显。ｙ组３周时可见皮肤溃疡形成，电镜见基底细胞层有凋亡细胞和凋亡小体形成，基底膜

Ultrastructural pathological research on skin radiation injury induced by high energy electrons in an animal model

Objective\ In his study an animal model of skin radiation injury was established to research the pathological change,mechanism of delayed necrosis,and difficulty in healing of ulcers induced by high energy electrons,the results of which would be based for further clinical research. Methods\ In this model the radiation injury on hip skin of SD mice was induced by 4 MeV electrons from an electron linear accelerator.Experimental animals were divided into four exposure dose groups:5 Gy,15 Gy,30 Gy,45 Gy.The pathological changes was observed macroscopically and by light and electron microscopy. Results\ The morphologic change of the 5 Gy group wasn't obvious under light\|microscope but was evident under electron microscope,including swelling of spinous cells,pyknosis of nuclei in cells of stratum basale and chromatin margination,endothelial swelling and nuclear pyknosis in microvessels,decrease in microvessel diameter,the dermal interstitial edema and break of collagenous fibrils.In the 15 Gy group the swelling was obvious in spinous and basal cells.The amount of microfibrils,desmosomes and hemidesmosomes decreased remarkably in basal cells.There was degeneration in vessel endoethelium and hair follicle epithelium.In the 30 Gy group,swelling and pyknosis were evident in spinous cells and basal cells.In the 45 Gy group skin ulcers could be seen.Apoptosis and disruption of basement membrane were seen in stratum basal.There were thrombosis in capillaries and chromatin margination in fibroblasts. Conclusion\ The degree of ultrastructurall changes in skin with radiation injury induced by high energy electrons is directly related to exposure dose.The swelling of mitochondria and endoplasmic reticulum,apoptosis in basal cells,swelling,pyknosis,cavity narrowing and thrombosis in microvessels,disruption of collagenous fibrils and apotosis in fibroblasts can be observed.These findings provide morphologic basis for study of radiation skin injury and difficulty in healing of skin ulcers induced by high energy electrons.The mechanism of delayed trauma healing waits for further research.