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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 radioactive 125I particles on the morphology of rat dorsal root ganglion (DRG) and surrounding tissues. Methods: Twenty-four adult male Sprague-Dawley rats were randomly divided into four groups: blank control group (A), 0.4 (B), 0.6 (C) and 0.8 (D) mCi (1Ci = 3.7 × 1010Bq) 6 only. 125I particles with different activities were implanted into the left lumbar 5 (L5) DRG of rats in each group. And observed under CT to ensure the accuracy of particle implantation position. Each group was implanted with two 125I particles of the same activity. The activity of 125I particles in each group were 0, 0.4, 0.6 and 0.8 mCi, respectively. Sixty days after implantation, L5 DRG and surrounding muscle tissue of rats in each group were obtained surgically. Morphology was observed under light microscope and the rate of positive cells was calculated. Results: With the increase of radioactive activity of 125I particles, the degree of DRG cell injury increased from slight edema of cells, decrease of Nissl body to obvious swelling of cells, nucleus deflected to one side, nuclear pyknosis and nuclear fragmentation. At 0.8mCi DRG injury group the most serious. The positive cell rate also increased with increasing radioactivity. The rate of positive cells in the group of 0.8mCi 60 days was (73.80 ± 2.38)%. Muscle tissue injury around the DRG is similar to DRG. CONCLUSIONS: Radioactive 125I particles implanted near the foramen may cause radiation damage to DRG cells and surrounding muscle tissue. The higher the activity of radioactive particles, the greater the degree of cell damage.