[Effect of the adenosine A1 receptor agonist on demyelination and remyelination processes in lysolecithin induced demyelination in rat optic chiasm]

ABSTRACT

Demyelination in central nervous system is usually followed by remyelination; however, chronic lesions with subsequent functional impairment result from the eventual failure of remyelination process, as seen in multiple sclerosis. Remyelination is the process through which oligodendrocyte-progenitor cells [OPCs] restore new myelin sheathes around demyelinated axons. This study aimed to investigate the effect of A1 receptor agonist, N6-cyclohexyladenosine [CHA], on the demyelination and remyelination processes in rat optic chiasm following lysophosphatidylcholine [LPC]-induced demylination. In this experimental study, LPC was injected into the optic chiasm of three groups of rats [n=6]. Control group received aCSF on different days following LPC injection. Two groups of animals received CHA on days 0-14 or 14-28 post-lesion. Demyelination and remyelination levels were evaluated by recording visual evoked potential [VEP] from the scalp. The highest level of demyelination was occurred on day 7 post-lesion LPC injection and gradually reduced during the days 7-28. The P-wave latency was significantly increased on day 7 and then partially restored during the days 7-28 post-lesion. CHA administration during the days 0-14 attenuated demyelination process. In addition, CHA administration in remyelination phase [days 14-28] was able to potentiate the endogenous myelin repair. Injection of CHA could prevent the lysolecithin-induced variations in VEP. The effects of CHA may be mediated through increment of OPCs proliferation and their differentiation into myelinating oligodendrocytes