Study of Alterations in Neurotrophin Expression in Chronic Spinal Cord Compression

神经营养因子在轻度脊髓压迫中的表达调控尚未得到详细研究，特别是其对运动神经元的影响。因此，我们研究了大鼠脊髓压迫（SCC）模型和对照动物运动神经元中BDNF和NGF的水平。观察脊髓鳞癌大鼠和对照组脊髓C4、C5-6、C7节段BDNF和NGF的表达模式。25周SCC大鼠运动神经元压缩区BDNF表达增加。相反，运动神经元中βNGF的表达在三个节段均逐渐下降。这种减少可能是由于proNGF加工的减少，该加工促进了proNGF的表达并降低了成熟NGF的水平。在9周的SCC大鼠中，在前角和压缩区周围的白质中观察到强烈的BDNF阳性胶质细胞。这些结果表明，BDNF的上调有助于运动神经元的再生和运动麻痹的改善。相反，NGF可能通过增加proNGF水平诱导运动神经元凋亡，类似于在阿尔茨海默病中观察到的变化。

The regulation of neurotrophic factor expression in mild spinal cord compression has not been investigated in detail, especially in regards to their effects on motoneurons. Therefore, we investigated the levels of BDNF and NGF, in motoneurons of a rat spinal cord compression(SCC) model developed by us and control animals. The expression pattern of BDNF and NGF were examined in spinal segments C4,C5-6,C7 in SCC and control rats. BDNF expression in motoneurons increased at the compressed region in 25-week SCC rats. In contrast, βNGF expression in the motoneurons decreased gradually in all three segments. This decrease may be due to a decrease in the processing of proNGF, which promotes proNGF expression and decreases the levels of mature NGF. In 9-week SCC rats, intensely BDNF positive glial cells were observed in the anterior horn and white matter around the compressed region. These results suggest that the upregulation of BDNF contributes to regeneration in motoneurons and an improvement of motor paresis. In contrast, NGF may induce motoneuron apoptosis through increased proNGF levels, similar to changes observed in Alzheimer's disease.