Astrocytes directly clear myelin debris through endocytosis pathways and followed by excessive gliosis after spinal cord injury

Abstract

Persisted myelin debris inhibit axon regeneration and contribute to further tissue damage after spinal cord injury (SCI). The traditional view is that myelin debris is mainly cleared by microglia and macrophages, while astrocytes cannot directly engulf myelin debris because they are absent from lesion core. Here, we definitely showed that astrocytes could directly uptake myelin debris both in vitro and in vivo to effectively complement the clearance function. Therefore, it can be shown that astrocytes can exert myelin clearance effect directly and indirectly after spinal cord injury. The damaged myelin debris was transported to lysosomes for degradation through endocytosis pathways, finally resulting in excessive gliosis. This process may be a potential target for regulating neural tissue repair and excessive glia scar formation after SCI.