大鼠脊髓腰节段神经营养因子及其受体的增龄变化

Aging-variation of neurotrophic factors and their receptors in lumbar spinal cord of age-increasing rats

目的观察不同月龄(1、3、6、12、18和24月龄)大鼠脊髓腰节段神经营养因子及其受体的变化,探讨其与增龄之间的关系。方法用免疫组织化学和Western blot法观察脊髓腰节段神经营养因子及其受体的表达,用尼氏染色法观察脊髓腰节段存活神经元数量。结果大鼠脊髓腰节段神经生长因子(NGF)及其受体TrkA、脑源性神经营养因子(BDNF)及其受体TrkB和胶质细胞源性神经营养因子(GDNF)表达具有明显的随增龄变化规律,即1月龄(幼年期)时表达量较低,随年龄增高逐渐上升,至6月龄(青年期)达高峰,24月龄(老年期)明显减低,其中以GDNF的变化更为明显。大鼠脊髓腰节段存活神经元数量在1月龄至6月龄均保持在较高水平,之后开始逐渐下降,24月龄时降至最低。结论神经营养因子及其受体在大鼠脊髓腰节段中的表达存在增龄变化,特别是老年期表达量显著降低,可能是导致脊髓老化的重要机制之一。

Objective To observe the changes in neurotrophic factors and their receptors in the lumbar spinal cord of aging rats （ 1, 3, 6, 12, 18 and 24 months）, and to investigate their correlation with gowth. Methods The expression of neurotrophic factors and their receptors in the lumbar spinal cord of rats were measured by immunohistochemistry and western blot. Nissl staining was used for quantitative detection of survival neurons. Results The expression of nerve growth factor （NGF） and its receptor TrkA, brain derived neurotrophic factor （BDNF） and its receptor TrkB and gliocyte derived neurotrophic factor （GDNF） in lumbar spinal cord of rats showed changes in relation to the aging process. Their expression was lower at the age of 1 month, reached the peak at 6-month, and decreased significantly at 24 months, in which the decline of GDNF was more obvious. The number of survival neurons in lumbar spinal cord kept at a high level from 1 to 6-month, then decreased gradually, and reached the lowest level at the age of 24 months. Conclusion The expression of neurotrophic factors and their receptors change with aging process, decreases in aged rats especially, which may be one of the mechanisms involved in spinal cord aging.