顺铂联合放射治疗对大鼠脊髓损伤影响的观察

Morphological Observation of the Rats Spinal Cord Injury Induced by Combined Treatment With Cisplatin and Radiation

目的探讨顺铂(c isp latin,DDP)联合放射治疗对大鼠脊髓损伤的影响。方法40只W istar大鼠随机分为5组,即空白组、单纯化疗组、单纯放射组、先化后放组和先放后化组。单化组单次腹腔注射顺铂5 mg/kg。单放组和放化联合组采用瓦里安2300 C/D直线加速器6M eV电子线照射大鼠胸段脊髓,照射野为2 cm×4 cm,5Gy/次,隔日1次,总剂量为40 Gy。联合组顺铂与照射的间隔时间为3天。照射结束后5个月,行活体灌注固定,取材,光镜和电镜观察脊髓的形态学变化。结果光镜下,CT组灰质未见改变,白质内部分有髓神经纤维排列紊乱,部分髓鞘板层结构松解、扭曲。RT组灰质未见改变,白质出现部分水肿坏死,髓鞘板层模糊不清。CT+RT组脊髓灰质、白质改变明显,其中CT+放疗组的灰质内可见到明显的神经元核变成细长形,尼氏体数量减少,白质出现大片坏死。电镜下,CT组髓鞘结构出现轻度变化,表现为部分髓鞘的板层结构松解、扭曲。RT组脊髓损伤表现为板层结构水肿、粘连,模糊不清。CT+RT组的脊髓损伤程度严重,表现为正常髓鞘的板层结构完全消失,轴突及神经纤维裸露,血管增生,部分血管内皮细胞坏死。RT+CT组脊髓损伤表现为正常髓鞘的板层结构部分松解、扭曲、断裂。结论顺铂与放疗联用明显加重脊髓损伤,且放疗前加用顺铂脊髓损伤加重。

Objective To explore the morphological change of the injuried spinal cord caused by the combination of cisplatin（CT） and radiotherapy（RT）. Methods 40 Wistar rats were divided into groups as following： normol control, CT, RT, CT ＋ RT, RT ＋ CT. The thoraxs of rats were irradiated with 6MeV electron beam of Varian 2300 C/D llne accelerator（5Gy/one time,total 40Gy,field size 2 ×4cm,3 days interval in RT,CT ＋ RT and RT ＋ CT groups ）. The rats were killed 5 months after irradiation and structures of the spinal cord were observed by light microscope and transmission electron microscope. Results In CT group, some of the myelinated nerve fibers were tuebu- lenced and swollen, the lamina of the myelin sheaths was incompact and twisting partly, but with no any change in gray matter. In RT group,the white matter was dropsical and necrosised partially,mith unclear myelin sheaths lamina. In CT ＋ RT and RT ＋ CT groups, long and thin nucleus, and decreased nissl body in number were observed with neerosed white matter,disappearance of myelin sheaths and exposed axon and myelinated nerve fibers were seen with hyperplastic blood vessels and necrosed endothelial cells. Conclusion The combination of cisplatin and RT caused the spinal cord injury of rats obviously with more serious injury by CT ＋ RT than by RT ＋ CT.