我们报道,在大鼠dMCAO模型中,浸润的Ly6C巨噬细胞仅在大脑皮层梗死处表达脑源性神经营养因子(BDNF)。然而,神经元表达的BDNF的变化,诱导Ly6C+细胞表达BDNF的生态位成分,这些成分的细胞来源,仍然不清楚。在这项研究中,在雄性大鼠大脑中动脉远端闭塞(dMCAO)后3、24和48h,进行免疫荧光双重染色以在脑切片上标记BDNF和Ly6C,并用Ly6C染色BDNF,IL-4R,和IL-10R.将中和抗IL-4抗体注射到梗死中,使用酶联免疫吸附试验测定梗死子区的IL-4和BDNF浓度。为了找出小胶质细胞的标志物IL-4的细胞来源,T细胞,和神经元分别与IL-4共染色。在某些梗塞亚区域,在中风后24-48小时内,主要的BDNF表达细胞迅速从NeuN+神经元转移到Ly6C+细胞,Ly6C+/BDNF+细胞主要表达IL-4受体。IL-4中和抗体注射后,BDNF,IL-4蛋白水平,BDNF+/Ly6C+细胞明显下降。该梗死子区中主要的IL-4表达细胞类型也不是神经元,但是免疫细胞,包括小胶质细胞,单核细胞,巨噬细胞,和T细胞。神经元,维持梗死周围区域的BDNF和IL-4表达。总之,在大鼠dMCAO模型的特定脑区,免疫细胞分泌的IL-4是Ly6C+细胞表达BDNF的主要诱导因子之一。
We reported that infiltrated Ly6C+ macrophages express brain-derived neurotrophic factor (BDNF) only at the cerebral cortex infarct in a rat dMCAO model. However, the changein neuron-expressed BDNF, the niche components that induce the Ly6C+ cells to express BDNF, and the cellular sources of these components, remain unclear. In this study, immunofluorescence double staining was performed to label BDNF and Ly6C on brain sections at 3, 24, and 48 h following distal middle cerebral artery occlusion (dMCAO) of male rats, and to stain BDNF with Ly6C, IL-4R, and IL-10R. A neutralizing anti-IL-4 antibody was injected into the infarct, and the IL-4 and BDNF concentrations in the subareas of the infarct were determined using enzyme-linked immunosorbent assay. To find out the cellular sources of IL-4, the markers for microglia, T cells, and neurons were co-stained with IL-4 separately. In certain infarct subareas, the main BDNF-expressing cells shifted quickly from NeuN+ neurons to Ly6C+ cells during 24-48 h post-stroke, and the Ly6C+/BDNF+ cells mostly expressed IL-4 receptor. Following IL-4 neutralizing antibody injection, the BDNF, IL-4 protein levels, and BDNF+/Ly6C+ cells decreased significantly. The main IL-4-expressing cell type in this infarct subarea is not neuron either, but immune cells, including microglia, monocyte, macrophages, and T cells. The neurons, maintained BDNF and IL-4 expression in the peri-infarct area. In conclusion, in a specific cerebral subarea of the rat dMCAO model, IL-4 secreted by immune cells is one of the main inducers for Ly6C+ cells to express BDNF.