Brazelton Timothy R, Nystrom Michael, Blau Helen M
Baxter Laboratory in Genetic Pharmacology, Stanford University School of Medicine, 269 W. Campus Drive, Stanford, CA 94305-5175, USA.
Dev Biol. 2003 Oct 1;262(1):64-74. doi: 10.1016/s0012-1606(03)00357-9.
While numerous reports indicate that adult bone marrow-derived cells can contribute to nonhematopoietic tissues in vivo in adult mice, the generally low frequency of these events has made it difficult to study the molecular and cellular pathways involved. Here, we show a 1000-fold range in the frequency with which diverse skeletal muscles incorporate adult bone marrow-derived cells in adult mice. Most striking was the finding of one specific muscle, the panniculus carnosus, in which up to 5% of myofibers incorporated bone marrow-derived cells over a 16- month period in the absence of experimentally induced selective pressure. These results suggest that muscles differ physiologically, establishing the panniculus carnosus as an assay for identifying the key regulators, such as trophic, homing, and differentiation factors, as well as the relevant cells within the bone marrow that are capable of circulating throughout the periphery and contributing to adult, nonhematopoietic tissues, such as skeletal muscle. Finally, the 5% incorporation of adult stem cells into skeletal muscle is the highest reported to date in the absence of experimentally induced selective pressure and is at a level that may be consistent with improving the function of defective muscle tissue.
尽管众多报告表明，成年小鼠体内源自成年骨髓的细胞可分化为非造血组织，但这些事件的发生频率通常较低，这使得研究其中涉及的分子和细胞途径变得困难。在此，我们发现成年小鼠体内不同骨骼肌摄取成年骨髓来源细胞的频率相差1000倍。最引人注目的是，在没有实验诱导的选择压力的情况下，特定肌肉——颈阔肌——在16个月的时间里，高达5%的肌纤维摄取了骨髓来源的细胞。这些结果表明，不同肌肉在生理上存在差异，从而确立了颈阔肌作为一种检测方法，用于识别关键调节因子，如营养因子、归巢因子和分化因子，以及骨髓中能够在外周循环并参与成年非造血组织（如骨骼肌）形成的相关细胞。最后，在没有实验诱导的选择压力的情况下，成年干细胞5%的骨骼肌摄取率是迄今为止报告的最高水平，这一水平可能与改善有缺陷的肌肉组织功能相一致。
