SD大鼠放射性脊髓损伤后形态学变化及凋亡表达

Morphological changes and apoptosis expression after radioactive spinal cord injury in SD rats

目的观察大剂量电子线放射治疗对SD大鼠脊髓损伤及其凋亡的影响。方法将30只SD大鼠随机分为对照组和实验组两组,每组各15只。实验组采用5 MeV电子线照射胸部中段脊髓,照射剂量为5 Gy/次,总剂量为40 Gy。照射结束后,心脏灌注取脊髓组织行HE染色和透射电镜观察脊髓组织的形态学变化,免疫组化检测凋亡相关蛋白Bax、Bcl-2和Caspase-3的表达,流式检测其凋亡水平。结果HE染色实验组的脊髓白质神经纤维紊乱排列,部分灰质细胞肿胀、破坏,细胞固缩。透射电镜结果为髓鞘板层模糊不清、粘连。免疫组化结果显示对照组凋亡基因Bcl-2表达量多,实验组表达的Bax和Caspase-3阳性细胞增加(P<0.05)。流式凋亡检测表明对照组的细胞凋亡率显著低于实验组(P<0.05)。结论大剂量电子线放射治疗会造成SD大鼠放射性脊髓损伤,凋亡相关蛋白在放射性脊髓中过表达,凋亡率明显增加。

Objective To observe the effect of high dose electron beam radiotherapy on spinal cord injury and apoptosis in SD rats.Methods Thirty SD rats were randomly divided into control group and experimental group,fifteen rats in each group.In the experimental group,5MeV electronic wire was used to illuminate the mid-thoracic spinal cord,and the radiation dose was 5Gy/time,and the total dose was 40Gy.After the end of irradiation,the spinal cord tissues were collected for HE staining and transmission electron microscope was used for observation of morphological changes of the spinal cord tissues.The expressions of apoptosis-related proteins Bax,bcl-2 and caspase-3 were detected by immunohistochemistry,and the level of apoptosis was detected by flow cytometry.Results HE staining showed that in the experimental group the white matter nerve fibers of the spinal cord were arranged in disorder,and some gray matter cells were swollen,damaged and pyknotic.The results of transmission electron microscope showed that the lamina layer of myelin sheath was blurred and adhered.Immunohistochemical results showed that the expression level of apoptotic gene bcl-2 was high in the control group,while the numbers of Bax and caspase-3 positive cells increased in the experimental group(P<0.05).Flow cytometry showed that the apoptosis rate of the control group was significantly lower than that of the experimental group(P<0.05).Conclusions High-dose radiation therapy may cause spinal cord injury in SD rats,and apoptosis-related proteins are over expressed in the radioactive spinal cord,and the apoptosis rate is significantly increased.