Perineuronal nets are extracellular matrix structures that surround neuronal cell bodies and their proximal dendrites in the central nervous system. Chondroitin sulfate proteoglycans, which contain chondroitin sulfates (CSs) are major components of perineuronal nets. CSs are considered to have inhibitory roles in neural plasticity, although the effects differ according to their sulfation pattern. In the present study, we investigated the expression of the CS subtypes CS-A and CS-C surrounding spinal motoneurons in different postnatal periods to explore the potential influence of altered CS sulfation patterns on spinal development.

CS-A−positive structures were observed around motoneurons in the cervical, thoracic, and lumbar segments as early as postnatal day (P) 5. Most motoneurons were covered with CS-A−positive structures during the first 2 postnatal weeks. The percentage of motoneurons covered with CS-A−positive structures decreased after P20, becoming lower than 70% in the cervical, and lumber segments after P35. CS-C−positive structures were occasionally observed around motoneurons during the first 2 postnatal weeks. The percentage of motoneurons covered with CS-C−positive structures increased after P20, becoming significantly higher after P25 than before P20. The expression pattern of Wisteria Floribunda agglutinin-positive structures around motoneurons was similar to that of the CS-C−positive structures.

The present findings revealed that CS-A and CS-C are differentially expressed in the extracellular matrix surrounding motoneurons. The altered sulfation pattern with increased CS-C expression is associated with the maturation of perineuronal nets and might lead to changes in the motoneuron plasticity.

神经周围网是中枢神经系统中围绕神经元细胞体及其近端树突的细胞外基质结构。硫酸软骨素蛋白多糖含有硫酸软骨素 (CS)，是神经元周围网络的主要成分。 CS 被认为对神经可塑性具有抑制作用，尽管其效果根据其硫酸化模式而有所不同。在本研究中，我们研究了出生后不同时期脊髓运动神经元周围的CS亚型CS-A和CS-C的表达，以探讨改变的CS硫酸化模式对脊柱发育的潜在影响。

早在出生后第 5 天（P），就在颈椎、胸椎和腰椎段的运动神经元周围观察到 CS-A 阳性结构。在出生后的前 2 周内，大多数运动神经元被 CS-A 阳性结构覆盖。 P20后，覆盖有CS-A阳性结构的运动神经元的百分比下降，P35后颈椎和腰部节段的运动神经元比例低于70%。在出生后的前 2 周内，偶尔在运动神经元周围观察到 CS-C 阳性结构。 P20后覆盖有CS-C−阳性结构的运动神经元的百分比增加，P25后明显高于P20前。运动神经元周围紫藤凝集素阳性结构的表达模式与 CS-C−阳性结构的表达模式相似。

目前的研究结果表明，CS-A 和 CS-C 在运动神经元周围的细胞外基质中差异表达。随着 CS-C 表达增加而改变的硫酸化模式与神经周围网络的成熟相关，并可能导致运动神经元可塑性的变化。