GEMSP exerts a myelin-protecting role in the rat optic nerve

Abstract

Objectives: Chronic experimental autoimmune encephalomyelitis (EAE) was induced in rats to evaluate the potential protective effect of GEMSP, a mixture made up of fatty acids (FA), vitamins, and amino acids or their derivatives, linked to Poly-L-Lysine, on the myelin sheath of the optic nerve.

Methods: To evaluate the effects of GEMSP on the optic nerve, animals were divided into three experimental groups: (1) EAE rats treated with GEMSP; (2) EAE rats treated with 0·9% NaCl; and (3) control, non-EAE rats. Using electron microscopy, we investigated the possibility that this new drug candidate has a myelin-protective role.

Results: A marginally significant reduction in the thickness of the myelin around optic nerve medium-size axons (diameter between 0·8–1·3 μm) was found in EAE rats. Treatment of EAE rats with GEMSP ameliorated myelin damage. Significantly increased myelin thickness was found when animals in groups 2 and 3 were compared. However, the number of myelinated axons studied was not altered in groups 1 or 2 when compared to controls.

Discussion: Our results suggest that in a model of demyelination, GEMSP protects and enhances the formation of the myelin sheath of the optic nerve and therefore could be a potential drug candidate to reduce optic nerve pathogenesis in multiple sclerosis (MS).

Keywords:

• Demyelination
• Experimental autoimmune encephalomyelitis (EAE)
• Multiple sclerosis (MS)
• Optic nerve

This work has been supported by GEMACBIO (St Jean d'Illac, France), the Institut pour le Developpement de la Recherche en Pathologie Humaine et Therapeutique (IDRPHT) (Talence, France), Red de Terapia Celular de Castilla y León (Spain), Consejería de Educación de la Junta de Castilla y León (Spain) (Ref.: SA099A08), the INCYL-Federación de Cajas de Ahorro de Castilla y León (Spain) and Ministerio de Educación y Ciencia (Spain) (Ref.: SA F2007-62060), Grupos Consolidados del Gobierno Vasco (2010-2015), RETICS Red Patología Ocular RD07/0062, BIOEF08/ER/006. The technical assistance of Ms Belén Armario is gratefully acknowledged. The authors gratefully acknowledge Dr Jennifer Higginson for the English revision of the manuscript.