实验动物瘢痕模型经^(90)Sr照射后超微结构的变化

Ultrastructural changes of animal scar models after being exposed to radionuclide ^(90)Sr

目的 :观察实验动物微型猪瘢痕模型经90 Sr照射后的超微结构改变 ,从形态学角度探讨90 Sr防治瘢痕的作用机制以及最有效治疗时间和剂量 ,为临床应用提供形态学基础。方法 :采用西双版纳微型猪 ,于面部、背部两侧制作 1cm× 2cm、深达皮下组织的创口数个 ,随机分为实验组和对照组。实验组于术后 1周用90 Sr敷贴器照射 ,剂量分别为 2 0 0、4 0 0、6 0 0、80 0、1 0 0 0、2 0 0 0、4 0 0 0cGy。然后在照射后 1 ,3,7,1 1周 (即术后 2 ,4 ,8,1 2周 ) ,分别切取对照组和实验组的瘢痕组织 ,进行透射电镜 (TEM)观察。结果 :小、中剂量 ( 2 0 0～ 6 0 0cGy) 90 Sr显著促进伤口毛细血管和成纤维细胞增生 ,成纤维细胞表现为数量多 ,体积大、粗面内质网增多并扩张 ,胶原纤维排列致密 ;大剂量 ( 80 0～ 2 0 0 0cGy) 90 Sr照射能显著抑制成纤维细胞增生 ,表现为数量少 ,体积小 ,粗面内质网欠丰富 ,核异染色质丰富 ,胶原纤维排列稀疏。结论 :小中剂量90 Sr照射能促进成纤维细胞合成胶原纤维 ,从而促进伤口愈合 ,临床上可在伤后早期进行照射 ,剂量为 2 0 0～ 6 0 0cGy ;大剂量90 Sr照射可抑制成纤维细胞合成胶原纤维的能力。为防治瘢痕过度增生 ,临床上可在伤口愈合后进行照射 ,剂量为 1 0 0 0～ 2 0 0 0cGy。

The ultrastructural changes of scar tissue of experimental micropigs after being exposed to 90 Sr applicator were observed by electron microscopy. The exposure time and the most effective dose of 90 Sr for prevention of scar formation were studied. Small and medium dose (200～600cGy) of 90 Sr irradiation accelerated the capillaries and fibroblasts proliferation. There were many rough endoplasmic reticulum (RER) in the cytoplasm of fibroblasts and abundant of loosened collagenous fibers scattered in the intercellular space randomly. Large dose (800～2000cGy) of 90 Sr irradiation inhibited the multiplication of fibroblasts. Fibroblasts showed less RER and rich in heterochomatin. These results suggested that the small and medium dose of 90 Sr irradiation may accelerate wound healing, while large dose of 90 Sr irradiation may prevent and treat hypertrophic scar tissue.