Protective effects of bone marrow-derived mononuclear cells in young mice on ischemic brain damage

据报道，循环中的骨髓源性内皮祖细胞起源于骨髓源性单个核细胞(BMCs)，并与微血管系统的动态平衡有关。循环内皮祖细胞水平降低，与衰老相关，与一系列心血管疾病的不良临床结局相关。在这里，我们将幼年小鼠的骨髓细胞(=yBMCs)移植到脑缺血前后的老龄小鼠体内。老龄小鼠在缺血前移植yBMCs可减少缺血性脑损伤，而在缺血后移植yBMCs的动物则不能。此外，移植了在缺血前去除CD34阳性细胞的yBMCs的老年小鼠也减少了缺血性脑损伤。虽然还需要进一步的研究来阐明脑血管衰老的基本机制，但我们的结果表明，CD34以外的因素对缺血性脑损伤具有保护作用的可能性。

Circulating bone marrow-derived endothelial progenitor cells have been reported to beoriginated from bone marrow-derived mononuclear cells (=BMCs) and implicated in homeostasis of the microvasculature. Decreased levels of circulating endothelial progenitor cells, associated with aging correlate with poor clinical outcomes in a range of cardiovascular diseases. Herein, we transplanted BMCs from young mice (=yBMCs) into aged mice before and after cerebral ischemia. Aged mice transplanted with yBMCs before ischemia reduced ischemic brain damage whereas animals transplanted with yBMCs after ischemia did not. Furthermore, aged mice transplanted with yBMCs depleted of CD34 positive cells before ischemia also reduced ischemic brain damage. Although further investigations must be required to elucidate the fundamental mechanism underlying senescence of the brain vasculature, our results shows the possibility that factors other than CD34 have protective effects on ischemic brain damage.