Demyelination secondary to chronic nerve compression injury alters Schmidt–Lanterman incisures

Abstract

The role of Schmidt-Lanterman incisures (SLIs) within the myelin sheath remains the subject of much debate. Previous studies have shown a positive correlation between the number of SLIs per internode and internodal width for both normal and pathological myelin internodes. As chronic nerve compression (CNC) injury induces demyelination, we sought to evaluate if CNC injury altered the occurrence of SLIs using nerve-teasing techniques and light microscopy. Rigorous examination of the teased axons from nerves subjected to CNC injury for 1 month, 2 months or 8 months revealed that there is indeed a positive correlation between the number of SLIs per internode and the internodal width. However, unlike previous studies, the degree of positive correlation between these two parameters was greater in the internodes that had undergone remyelination in response to CNC injury as compared with the internodes from control nerves. These findings support the theory that SLIs are likely to assist in the metabolic processes of the myelin sheath, including growth and maintenance of the myelin sheath.

Functional assessment after sciatic nerve injury in a rat model

“…17 Our previously published research has consistently demonstrated that the dimensions of the tube are sufficient to cause compression without causing deformity to the nerve and thereby, inducing a progressive decrease in nerve conduction velocity. 16,17,[26][27][28][29][30][31][32][33] With the development of this rat model for CNC, we had found that tubing that constrained the nerve caused scarring at the site and subsequent axonal loss which is a different pathology from conditions seen in humans such as carpal tunnel syndrome. The tubing with its current dimensions comes into contact with the nerve and is able to transmit sufficient pressure to cause the subsequent changes we have observed in repeated studies at the cellular level.…”

Intra-axonal calcium changes after axotomy in wild-type and slow Wallerian degeneration axons

“…Furthermore, the altered appearance, i.e. increased prominence of pre-existing incisures during Wallerian degeneration (Krinke et al, 1986) and the increased occurrence of SLCs in nerves consisting of new myelin after chronic nerve compression (Berger and Gupta, 2006) suggest a role of SLCs during degeneration and also in maintenance of the myelin sheath.…”

F‐actin distribution at nodes of Ranvier and Schmidt‐Lanterman incisures in mammalian sciatic nerves

“…Under different pathological conditions, the appearance of SLIs can be altered, suggesting that these structures might play a role in myelin maintenance [Berger and Gupta, 2006]. In human inherited peripheral neuropathies (i.e., Charcot-Marie-Tooth type 1A disease), the organization of myelinated nerve fibers is altered.…”