The transcriptomic profile of the hippocampal microglia in the irradiated juvenile mouse brain. The transcriptomic profile of the hippocampal microglia in the irradiated juvenile mouse brain

Cranial irradiation (IR), an effective tool to treat malignant brain tumors, triggers a chronic pro-inflammatory microglial response, at least in the adult brain. Using bulk RNA sequencing, we show that the microglial response in the juvenile mouse hippocampus is rapid, but returns toward normal within 1 week. The sensome of irradiated hippocampal microglia reveals an immediate response that declines after one day. Irradiation of the juvenile brain induces a highly ordered temporal progression of the inflammatory and phenotypic microglial genes Overall design: Mice were irradiated on postnatal-day 21 with radiation dose of 8Gy. Miced were sacrifced at different time points after irradiation (2h, 6h, 1day, and 1wk). After perfusion, the hippocampus was dissected and the micgloa were FACS isolated based on the expression of Cx3cr1 expression. Total RNA was isloated and processed for bulk RNA-Seq. Each time point consisted iof 6 sham control (SH) and 6 irradiated (IR) animals.

颅脑照射（Cranial irradiation, IR）是治疗恶性脑肿瘤的有效手段，至少在成年大脑中，其可诱发慢性促炎型小胶质细胞应答反应。本研究通过批量RNA测序（bulk RNA sequencing）发现，幼年小鼠海马体中的小胶质细胞应答进展迅速，但可在1周内恢复至正常水平。受照射海马体小胶质细胞的感知组（sensome）呈现即刻应答特征，该应答在1天后出现衰减。幼年大脑的放射线照射可引发炎症相关及表型相关小胶质细胞基因的高度有序的时间动态变化过程。实验设计：实验小鼠于出生后第21天接受8Gy剂量的放射线照射，分别在照射后的2小时、6小时、1天及1周四个时间点实施安乐死。经灌流固定后，分离小鼠海马体，并基于Cx3cr1的表达水平通过荧光激活细胞分选术（Fluorescence-Activated Cell Sorting, FACS）获取小胶质细胞。提取总RNA并进行批量RNA测序（bulk RNA-Seq）。每个时间点均设置6只假照射对照（SH）小鼠与6只照射组（IR）小鼠。