放射性(125)~I粒子植入对大鼠背根神经节及周围组织形态学的影响

Histomorphological Changes in Rat Dorsal Root Ganglion and Surrounding Tissues after Implanting the Radioactivity of (125)~I Seeds

目的:观察放射性125I粒子对大鼠背根神经节(DRG)及周围组织形态学的影响。方法:24只成年雄性SD大鼠随机分为空白粒子对照组(A)、0.4(B)、0.6(C)、0.8(D)mCi(1Ci=3.7×1010Bq)共4个剂量组,每组6只。将不同活度的125I粒子植入各组大鼠左侧腰5(L5)DRG周围。并在CT下观察以确保粒子植入位置的准确性。每组均植入2粒活度相同的125I粒子。各组125I粒子的活度分别为0、0.4、0.6、0.8mCi。于粒子植入后60d,手术获取各组大鼠L5DRG及周围肌肉组织,在光镜下行形态学观察并计算阳性细胞率。结果:随125I粒子放射活度的增加,DRG细胞损伤程度从出现细胞轻度水肿,尼氏小体减少到细胞肿胀明显,细胞核偏向一侧,核固缩、核碎裂现象增加。在0.8mCi组DRG的损伤最严重。阳性细胞率也随放射活度增大逐渐增加。0.8mCi组60d时的阳性细胞率达到(73.80±2.38)%。DRG周围肌肉组织的损伤类似于DRG。结论:近椎间孔处植入放射性125I粒子可对DRG细胞和周围肌肉组织造成放射损伤。放射性粒子的活度越高,细胞损伤的程度越严重。

Objective： To observe the effects of different radioactivity of seeds on the histomorphology of dorsal root ganglion（DRG）and surrounding tissues. Methods： Twenty four adult male Sprague-Dawley （SD） rats（220-250 g）were ran- domly assigned to four groups according to different radioactivity of ;125Ⅰ seeds, which was respectively named group A （0 mCi）, group B （0.4 mCi）, group C（0.6 mCi） and group D （0.8 mCi）. There were 6 rats in each group. ;25I seeds were implanted around dorsal root ganglion. Computed tomography was used to check the position of seeds to be in an accurate location around corre- sponding dorsal root ganglion. The125Ⅰdorsal root ganghon and the surrounding muscular tissues were obtained to observe the histomorphology of specimens by high-power optical microscope, and to calculate the ratio of positive cells, when all rats were killed 60 days after implanting seeds. Results： As the increased dose of radioactivity, the injury of DRG became more severe accordingly. The changes ranged from moderate cellular swelling, cell edema, decrease of Nissl＇ s body originally to more cel- lular swelling, more edema, the nucleus was not in the center and more karyopyknosis, fragmentation at last. The injury of DRG was the most severe in the 0.8 mCi group. In addition, the ratio of positive cells was also increased with the increase of radioactivity, which was （73.80±2.38）% in 0.8 mCi group as the highest positive ratio. The changes of muscular tissues around DRG were similar with DRG. Conclusion DRG and muscular tissues ai＇ound could be injured after implanting radio- active ;125Ⅰ around DRG. The severity of injury was increased as dose of 125Ⅰ increased.