大鼠脊髓硫酸软骨素蛋白多糖4细胞的生后发育特征

Postnatal development characteristics of NG2 cells in spinal cords of rats

目的研究大鼠脊髓中硫酸软骨素蛋白多糖4(NG2)细胞生后发育特征。方法采用免疫组织化学及West-ern blot,观察大鼠生后不同发育阶段的脊髓中NG2细胞形态变化。结果大鼠生后各发育阶段的脊髓内均有NG2阳性细胞表达;NG2细胞的胞体逐渐增大,其形态由圆形或卵圆形变为不规则形,突起数目和长度随之增加,与同时期大脑皮质的NG2细胞形态比较,脊髓内的NG2细胞胞体要大,突起短而少。P1d脊髓内NG2表达值最高,为0.75±0.11,P7d显著下降为0.40±0.05,P21d表达值降至最低,为0.16±0.06,P60d回升为0.37±0.06。结论在大鼠不同发育阶段的脊髓内,NG2细胞形态数量有所不同;P7d到P21d是脊髓内神经纤维髓鞘主要形成期;脊髓内NG2细胞可能处于少突胶质细胞系发育的早期阶段。

Objective To observe the postnatal development characteristics of NG2 cells in spinal cord of rats. Methods Immunohistochemistry （IHC） was applied to examine the morphologic characteristics of NG2 cells. Western blot was used to observe the expression of NG2 in spinal cord during the different postnatal developmental stages. Results NG2 cells persistently existed during different postnatal developmental stages in spinal cord. There were a great number of NG2 cells with few processes and round or oval cell bodies at P1 d. At P7d, a few NG2 cells were detected with short processes in spinal cord. But at P21d,few NG2 cells were found in spinal cord. At P60 d, NG2 cells with irregular cell bodies and 1 - 3 short processes were found. Compared with the cerebral cortex in the corresponding stages, NG2 cells in spinal cord showed bigger soma, shorter and thin processes. Western blot showed that the expression of NG2 at P1,7,21 and 60 d was （0.75 ±0. 11 ）, （0.40±0. 05）, （0. 16 ±0.06） and （0. 37_±0.06） respectively. NG2 expression was highest at Pld,declined at P7d and reduced significantly to the lowest at P21d,and then increased at P60d. Conclusions The NG2 cells persistently exist in spinal cord and are different in cell number and morphology at the different postnatal development stages. From P7d to P21d may be the majormyelination period. NG2 cells in spinal cord may be at an earlier stage in oligodendrocyte lineage.