Myelin ultrastructure of sciatic nerve in rat experimental autoimmune neuritis model and its correlation with associated protein expression

摘要

Objective:To explore the relationship of peripheral nerve ultrastructure and its associated pro-tein expression in experimental autoimmune neuritis ( EAN) . Methods:EAN was established in Lewis rats using an emulsified mixture of P0 peptide 180-199,Mycobacterium tuberculosis,and incomplete Freund's adjuvant. Rats given saline solution were used as a control group. Sciatic nerve ultrastructure and immunofluorescence histopathol-ogy were measured at the neuromuscular severity peak on day 18 post-induction. Cell-specific protein markers were used for immunofluorescence histopathology staining to characterize sciatic nerve cells:CD3 ( T cell) , Iba-1 ( mi-croglia), S100(myelin), and neurofilament 200(axon). Results:The results showed that swelling of the myelin lamellae, vesicular disorganization,separation of the myelin lamellae, and an attenuation or disappearance of the axon were observed by transmission electron microscopy in the EAN group. CD3 and Iba-1 increased significantly in the structures characterized by separation or swelling of the myelin lamellae,and increased slightly in the struc-tures characterized by vesicular of the myelin lamellae, S100 decreased in the structures characterized by vesicular disorganization or separation of the myelin lamellae. And neurofilament 200 decreased in the structures character-ized by separation of the myelin lamellae. Moreover,we found that Iba1 were positive in the myelin sheath, and o-verlapped with S100 , which significantly indicated that Schwann cells may play as macrophage-like cells during the disease progression of ENA. Our findings may be a significant supplement for the knowledge of EAN model, and may offer a novel sight on the treatment of GBS.