Journal Article

Forced Remyelination Promotes Axon Regeneration in a Rat Model of Spinal Cord Injury

Bekisz, Marek, Miazga, Krzysztof, Sławińska, Urszula, Kwaśniewska, Anna, Niedziółka, Sylwia, Yeghiazaryan, Marine, Zawadzka, Małgorzata

2022

Overview

Spinal cord injuries result in the loss of motor and sensory functions controlled by neurons located at the site of the lesion and below. We hypothesized that experimentally enhanced remyelination supports axon preservation and/or growth in the total spinal cord transection in rats. Multifocal demyelination was induced by injection of ethidium bromide (EB), either at the time of transection or twice during transection and at 5 days post-injury. We demonstrated that the number of oligodendrocyte progenitor cells (OPCs) significantly increased 14 days after demyelination. Most OPCs differentiated into mature oligodendrocytes by 60–90 dpi in double-EB-injected rats; however, most axons were remyelinated by Schwann cells. A significant number of axons passed the injury epicenter and entered the distant segments of the spinal cord in the double-EB-injected rats. Moreover, some serotoninergic fibers, not detected in control animals, grew caudally through the injury site. Behavioral tests performed at 60–90 dpi revealed significant improvement in locomotor function recovery in double-EB-injected rats, which was impaired by the blockade of serotonin receptors, confirming the important role of restored serotonergic fibers in functional recovery. Our findings indicate that enhanced remyelination per se, without substantial inhibition of glial scar formation, is an important component of spinal cord injury regeneration.

• Publisher: MDPI
• Subject: Animals / Axons - pathology / Demyelinating Diseases - pathology / Ethidium / Nerve Regeneration - physiology / Rats / Remyelination / Spinal Cord - pathology / Spinal Cord Injuries - pathology / Spinal Cord Regeneration