Kozlova Elena N
Neuroanatomy, Department of Neuroscience, Biomedical Center, PO Box 587, SE-751 23 Uppsala, Sweden.
Eur J Neurosci. 2003 Feb;17(4):782-90. doi: 10.1046/j.1460-9568.2003.02518.x.
Nerve fibre degeneration in the spinal cord is accompanied by astroglial proliferation. It is not known whether these cells proliferate in situ or are recruited from specific regions harbouring astroglial precursors. We found cells expressing nestin, characteristic of astroglial precursors, at the dorsal surface of the spinal cord on the operated side from 30 h after dorsal root injury. Nestin-expressing cells dispersed to deeper areas of the dorsal funiculus and dorsal horn on the operated side during the first few days after injury. Injection of bromodeoxyuridine (BrdU) 2 h before the end of the experiment, at 30 h after injury, revealed numerous BrdU-labelled, nestin-positive cells in the dorsal superficial region. In animals surviving 20 h after BrdU injection at 28 h postlesion, cells double-labelled with BrdU and nestin were also found in deeper areas. Labeling with BrdU 2 h before perfusion showed proliferation of microglia and radial astrocytes in the ventral and lateral funiculi on both sides of the spinal cord 30 h after injury. Nestin-positive cells coexpressed the calcium-binding protein Mts1, a marker for white matter astrocytes, in the dorsal funiculus, and were positive for glial fibrillary acidic protein (GFAP), but negative for Mts1 in the dorsal horn. One week after injury the level of nestin expression decreased and was undetectable after 3 months. Taken together, our data indicate that after dorsal root injury newly formed astrocytes in the degenerating white and grey matter first appear at the dorsal surface of the spinal cord from where some of them subsequently migrate ventrally, and differentiate into white- or grey-matter astrocytes.
脊髓中的神经纤维变性伴随着星形胶质细胞的增殖。目前尚不清楚这些细胞是在原位增殖还是从含有星形胶质前体细胞的特定区域募集而来。我们发现，在背根损伤后30小时，在手术侧脊髓的背表面有表达巢蛋白的细胞，巢蛋白是星形胶质前体细胞的特征性标志物。在损伤后的最初几天，表达巢蛋白的细胞分散到手术侧背侧索和背角的更深区域。在损伤后30小时实验结束前2小时注射溴脱氧尿苷（BrdU），结果显示在背侧浅表区域有大量BrdU标记的、巢蛋白阳性的细胞。在损伤后28小时注射BrdU后存活20小时的动物中，在更深区域也发现了BrdU和巢蛋白双标记的细胞。灌注前2小时用BrdU标记显示，损伤后30小时脊髓两侧腹侧和外侧索中的小胶质细胞和放射状星形胶质细胞发生增殖。在背侧索中，巢蛋白阳性细胞共表达钙结合蛋白Mts1，这是白质星形胶质细胞的标志物，并且对胶质纤维酸性蛋白（GFAP）呈阳性，但在背角中对Mts1呈阴性。损伤一周后，巢蛋白表达水平下降，3个月后无法检测到。综上所述，我们的数据表明，背根损伤后，变性白质和灰质中新生的星形胶质细胞首先出现在脊髓的背表面，其中一些随后从那里向腹侧迁移，并分化为白质或灰质星形胶质细胞。
