摘要
目的:探讨张力蛋白1（TNS1）对放射性脑损伤（RBI）小鼠认知功能的影响。方法:选用6周龄健康的C57BL/6小鼠共40只，体质量为（20±2）g，随机将其分为正常对照组（Control组）、单纯放射组（Rad组）、慢病毒敲低TNS1放射组（Rad+LV组，LV即TNS1干扰慢病毒）、对照慢病毒放射组（Rad+LV-NC组，LV-NC即空载慢病毒），每组10只小鼠。（1）RBI模型小鼠的建立：C57BL/6小鼠深度麻醉后固定于木板上，使用医用直线加速器对小鼠进行单次全剂量全脑放射性照射（30 Gy）。（2）各组干预如下，Control组：在进行放射时，仅进行麻醉，不进行放射处理；Rad组：与Rad+LV-NC组、Rad+LV组同时进行30 Gy单次全剂量放射性照射；Rad+LV组：脑立体定位注射TNS1敲低慢病毒，3周后行30 Gy单次全剂量放射性照射；Rad+LV-NC组：脑立体定位注射LV-NC空载慢病毒，3周后行30 Gy单次全剂量放射性照射。实验过程中持续观察各组小鼠生长情况和一般状况，并于放射性照射后第6周进行行为学测试，通过旷场实验、悬尾实验观察小鼠生长情况，通过新物体识别实验和水迷宫实验来检测小鼠的认知功能。结果:TNS1在RBI模型小鼠脑组织中表达量下降，差异有统计学意义（P＜0.05）；LV3慢病毒可有效敲低BV2细胞及脑组织中TNS1表达，差异有统计学意义（P＜0.05）；Control组、Rad组、Rad+LV-NC组、Rad+LV组小鼠体质量生长情况及旷场实验总路程等实验结果比较，差异均无统计学意义（P＞0.05）；新物体识别实验中与Rad组小鼠相比，Rad+LV-NC组、Rad+LV组小鼠识别系数无显著差异（P＞0.05）；水迷宫实验显示，与Control组相比，Rad组、Rad+LV-NC组、Rad+LV组小鼠的空间记忆能力削弱，而Rad+LV组在第2天和第6天的潜伏期更长（P＜0.05），第7天穿越平台时长更短（P＜0.05），穿越平台次数显著减少（P＜0.01），差异均有统计学意义。结论:放射性照射后小鼠认知功能损伤，脑组织中TNS1表达量下降；降低脑组织中TNS1的含量在一定程度上加重了RBI模型小鼠的认知损伤。
Abstract
Objective:To investigate the effect of tensin 1 (TNS1) on brain injury and cognitive function in animal models with radiation-induced brain injury.Methods:A total of 40 healthy 6-week-old C57BL/6 mice, with weight about (20±2) g, were randomly assigned into normal control group (Control group), radiation-only group (Rad group), knock-down lentiviral radiation group (Rad+LV group, LV stands for TNS1-interfering lentivirus), control lentiviral radiation group (Rad+LV-NC group, LV-NC stands for empty lentivirus), with ten mice in each group. (1) Establishment of radioactive brain injury model mice: C57BL/6 mice were fixed on a wooden board after deep anesthesia, and a single full-dose whole-brain irradiation (30 Gy) was administered to the mice using a medical linear gas pedal. (2) Control group: only anesthesia was administered without radiation treatment when radiation was administered; radiation-only group: a single full dose of 30 Gy was administered simultaneously with the Rad+LV-NC and Rad+LV groups; Rad+LV group: stereotaxic injection of TNS1 knockdown lentivirus, followed by 30 Gy single full-dose radiation three weeks later; Rad+LV-NC group:stereotaxic injection of LV-NC control lentivirus, followed by 30 Gy single full-dose radiation three weeks later. The growth and general condition of the mice in each group were continuously detected during the experiment, and behavioral tests were performed at 6 weeks after radiation. Mice's growth and emotion were observed through the open field experiment, the hanging tail experiment, the cognitive function of mice was tested by the old and new object recognition experiment and the water maze experiment.Results:TNS1 expression decreased in the brain tissue of radiation model mice (P＜0.05); LV3 lentivirus effectively knocked down TNS1 expression in BV2 cells and brain tissue (P＜0.05); there were no significant differences in body weight growth, and total distance traveled in the open field experiment among Control group, Rad group, Rad+LV group, and Rad+LV-NC group (P＞0.05); in the new object recognition experiment, there was no significant difference in cognitive coefficient beween Rad+LV-NC group and Rad+LV group compared with Rad group. The water maze experiment showed that compared with the normal control group, the spatial memory ability of mice in the radiation-only group, Rad+LV group and Rad+LV-NC group was weakened, respectively, while the Rad+LV group had a longer latency time on day 2 and day 6 (P＜0.05). The day 7 crossing platform duration was shorter (P＜0.05), and the number of crossing platforms was significantly reduced (P＜0.01); all differences were statistically significant.Conclusion:Cognitive impairment in mice after radiation exposure is performed, and TNS1 expression in brain tissue decreased after radiation exposure; reducing TNS1 content in brain tissue can aggravate cognitive impairment in radiation model mice to some extent.
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