Clarification of roles of gangliosides in nerve regeneration using mice lacking complex gangliosides

为了阐明神经节苷脂在神经功能（包括神经再生）中的作用或机制，使用缺乏复合神经节苷脂的小鼠进行了体内和体外研究。在体内研究中，对N-乙酰半乳糖胺-转移酶敲除（GalNacT-/-）小鼠的坐骨神经进行电生理学评价，并在挤压后间隔与野生型小鼠进行比较;挤压后4天的捏反射测试显示组间再生长度无差异。此外，神经传导研究也显示，坐骨胫神经复合肌肉动作电位和终末潜伏期在神经夹伤前和神经夹伤后7周之间没有差异。在体外研究中，MAG-Fc不与来自GalNacT-/-小鼠的小脑颗粒细胞结合，但与来自GD 3合酶-/-小鼠的小脑颗粒细胞部分结合，并且与来自wil型小鼠的小脑颗粒细胞良好结合。此外，通过神经丝染色评估那些结合蛋白与神经突延伸的幅度。鉴于GalNacT-/-小鼠不具有MAG的潜在配体GT 1b或GD 1a，而GD 3合酶-/-小鼠具有少量MAG配体，这些结果表明神经节苷脂可能在神经粘附或再生中发挥重要作用。

To clarify either the roles or mechanisms of gangliosides in nerve function including nerve regerneration, in vivo and in vitro studies were undertaken using mice lacking complex gangliosides. In in vivo study crushed sciatic nerves of N-acetylgalctosamine-transferase knockout (GalNacT-/-) mice were electrophysiologically evaluated and compared with wild-type mice at intervals after crush ; pinch reflex test 4 days after crush showed no difference in regeneration length between groups. In addition, nerve conduction study also showed no difference in compound muscle action potential and terminal latency of sciatic-tibial nerve before and up to 7 weeks after nerve crush between groups. In vitro study, MAG-Fc did not bind to cerebellar granular cells from GalNacT-/-mice, but partially bound to those from GD3 synthase-/-mice and well bound to those from wil type mice. Furthermore, those binding paralleled with the magnitude of neurite extension evaluated by staining of neurofilaments. In view of the fact that GalNacT-/- mice do not have GT1b or GD1a, potential ligand for MAG and GD3 synthase -/-mice have a small amount of MAG ligands, these results suggest that gangliosides may play an important role in nerve adhesion or regeneration.