γ射线对小鼠记忆及Ⅳ型胶原表达的影响

Effects of γ-rays on memory and expression of collagen Ⅳ in mice

目的建立放射性脑损伤模型,观察放射前后小鼠记忆、海马齿状回颗粒下层(SGZ)和室管膜下区(SVZ)Ⅳ型胶原的改变,探索放射性脑损伤的发生机制,探讨放射性脑损伤机制。方法 30只2月龄雌性昆明小鼠随机分为对照组、放射1d组、放射7d组,每组各10只,放射组给予^(60)Coγ射线照射,10Gy/次,隔天照射,共20Gy。放射前、后分别采用Morris水迷宫观察小鼠记忆能力的变化,于照射结束后1d、7d采用免疫组化方法观察海马齿状回的颗粒下层(subgranular zone,SGZ)和侧脑室的室管膜下区(subventricular zone,SVZ)内Ⅳ型胶原(CollagenⅣ)的表达变化情况。结果与对照组相比,放射后1d、7d组小鼠找到平台的时间明显延长,而穿越平台次数显著减少(P<0.01);SGZ和SVZ区内Ⅳ型胶原数量减少、表达减弱(P<0.05)。结论放射线干预可损害小鼠空间记忆能力,其机制可能与Ⅳ型胶原降解影响血管新生有关。

Objective The model of radiation brain injury was established to observe the changes of memory of mice with radiation brain injury and the changes of typeⅣ collagen in the subgranular zone（SGZ）and subventricular zone（SVZ）,and to explore the occurrence mechanism of radiation brain injury,so as to provide basis for its prevention and treatment. Methods Thirty 2-month-old female mice from Kunming were randomly divided into 3 groups：control group,1 dafter radiation group and 7 dafter radiation group,with 10 cases in each group.The radiation groups were irradiated by 60 Coγ-ray,10 Gy each time,every other day with the total dose of 20 Gy.The changes of mice memory ability before and after radiation were observed by Morris water maze.On 1 dand 7 dafter the end of irradiation,the expression of collagen Ⅳin subventricular zone（SVZ）and subgranular zone（SGZ）of hippocampal dentate gyrus were observed by immunohistochemical method. Results Compared with the control group,the time of finding the platform in the 1 dafter radiation group and 7 dafter radiation group prolonged and the times of crossing the platform decreased significantly（P〈 0.01）;the number of collagenⅣ positive cells in SGZ and SVZ reduced,and the expression weakened（P〈 0.05）. Conclusion Radiation intervention may damage the spatial memory ability of mice,and its mechanism may be related to the effect of typeⅣ collagen degradation on angiogenesis.