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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、45Gy 4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 ;15Gy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。 45Gy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 ,基底膜有缺损 ,毛细血管内有血栓形成 ,纤维母细胞染色质边集。结论 高能电子线皮肤辐射损伤超微结构病理改变程度同照射剂量大小直接相关 ,基底细胞核固缩 ,线粒体、内质网肿胀 ,出现凋亡小体血管内皮细胞肿胀 ,核固缩 ,血管腔狭小 ,毛细血管内血栓形成 ,胶原纤维断裂 ,纤维母细胞出现凋亡小体等超微结构改变 ,为高能电子线造成皮肤辐射损伤和溃疡难以愈合提供了
OBJECTIVE: To study the pathological changes and mechanism of delayed necrosis and difficult-to-heal healing of ulcer due to radiation damage of high-energy electron skin in animal model, and lay the foundation for further clinical research. Methods In this experiment, SD rat was used as the experimental object to irradiate the buttocks skin with a 4 MeV electron beam generated by a linear accelerator to make a skin radiation injury model. The experimental animals were divided into 5Gy, 15Gy, 30Gy and 45Gy groups. The pathological gross examination, light microscopy and electron microscopy were performed 2 months after one-time irradiation. Results The morphology of the light microscope in 5 Gy group was not obvious. Electron microscopy showed spongocytic swelling, pyknosis of basal cell nucleus, chromatin margination of nuclear membrane, swelling of vascular endothelial cell, partial nuclear condensation, narrow lumen and subcutaneous collagen fiber. In 15Gy group, the edema of spinous cells and basal cells were obvious, the intracellular cytoplasmic tension microfilaments, desmosomes and hemidesmosomes were significantly reduced, and the vascular endothelial cells and hair follicle epithelial cells were degenerated. The 30 Gy group showed spine cells and basal cell nucleus pyknosis and edema obviously under the electron microscope . The formation of skin ulcers was observed in the 45 Gy group at 3 weeks. The apoptotic cells and apoptotic bodies were found in the basal cell layer by electron microscopy. The basement membrane was deficient. Thrombus was formed in the capillaries and the chromatin margination of fibroblasts. Conclusion The pathological changes of the ultrastructures of radiation-induced skin lesions are directly related to the radiation dose. The basal cell nucleus pyknosis, swelling of mitochondria and endoplasmic reticulum, swelling of the apoptotic body endothelial cells, nuclear pyknosis, narrowing of the lumen, Capillary thrombosis, collagen fibers break, fibroblasts apoptotic bodies and other ultrastructural changes, high-energy electron rays caused by skin radiation damage and ulcers difficult to heal provided