Yang Zuozhang, Jin Congguo, Chen Ting, Sun Hongpu, Yang Dakuan, Huang Yunchao, Zhang Jin, Zhao Ruilian, Zhang Jinlei
Department of Orthopedics, Tumor Hospital of Yunnan Province, The Third Affiliated Hospital of Kunming Medical College, Kunming, Yunnan 650118, P.R. China.
Oncol Lett. 2012 Feb;3(2):315-320. doi: 10.3892/ol.2011.489. Epub 2011 Nov 17.
Brachytherapy is regarded as the most effective method in the treatment of metastatic spinal tumors since little damage is caused to surrounding healthy tissue. However, this method may cause radiation myelopathy if an overdose occurs. In the present study, we established a Banna mini-pig (125)I spinal cord implantation model to provide a tool for the study of how to reduce these types of side effects. Cell cycle alteration, apoptosis and necrosis of spinal cord neurons in the presence of various doses and durations of (125)I brachytherapy were also investigated. The pigs were randomly divided into four groups, A, B, C and D. In group A, four (125)I seeds (total radioactivity, 4.0 mCi) were implanted into the dura mater of the spinal canal at the level of T13. In groups B and C, eight (125)I sources (total radioactivity, 8.0 mCi) were inserted at the same location. Groups A and C were raised for up to 8 months and group B for only 2 months. Neurons from the swine spinal cord at the T13 level were collected and cell cycle analysis was performed. Apoptosis and necrosis were tested by a terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) assay. The Banna mini-pig brachytherapy model was successfully established. Radiation myelopathy was closely associated with radiation dose and duration, more neurons were blocked in the G2 and S phases as dose and time increased, and an increase in apoptosis and necrosis was detected. Ratios of apoptosis and necrosis were reduced as lower doses and shorter durations of radiation were applied. Our results demonstrate that the Banna mini-pig is an ideal animal to study (125)I brachytherapy. Low-dose and short-term brachytherapy may effectively decrease apoptosis and necrosis in spinal cord cells in Banna mini-pigs.
近距离放射治疗被认为是治疗转移性脊柱肿瘤最有效的方法，因为对周围健康组织造成的损伤较小。然而，如果出现剂量过量，这种方法可能会导致放射性脊髓病。在本研究中，我们建立了版纳微型猪碘-125脊髓植入模型，以提供一个研究如何减少这类副作用的工具。我们还研究了在不同剂量和照射时间的碘-125近距离放射治疗下脊髓神经元的细胞周期改变、凋亡和坏死情况。将猪随机分为A、B、C和D四组。A组在T13水平将4颗碘-125种子（总放射性活度为4.0毫居里）植入椎管硬脑膜。B组和C组在同一位置插入8颗碘-125源（总放射性活度为8.0毫居里）。A组和C组饲养长达8个月，B组仅饲养2个月。收集T13水平猪脊髓的神经元并进行细胞周期分析。通过末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）法检测凋亡和坏死情况。成功建立了版纳微型猪近距离放射治疗模型。放射性脊髓病与放射剂量和照射时间密切相关，随着剂量和时间增加，更多神经元阻滞于G2期和S期，并且检测到凋亡和坏死增加。当应用较低剂量和较短照射时间时，凋亡和坏死的比例降低。我们的结果表明，版纳微型猪是研究碘-125近距离放射治疗的理想动物。低剂量和短期近距离放射治疗可能有效减少版纳微型猪脊髓细胞的凋亡和坏死。
