Abstract
Experimental autoimmune neuritis (EAN) serves as a model for studying autoimmune peripheral neuropathies. This study investigated the effects of a sphingosine-1-phosphate receptor 5 (S1Pr5) agonist on EAN recovery and nerve regeneration. Lewis rats with induced EAN were treated with the S1Pr5 agonist A-971432. Clinical scores, cytokine production, and expression of regeneration factors were analyzed. Histological examination of the cauda equina was also performed. Treatment with the S1Pr5 agonist promoted recovery of clinical symptoms in the later stages of EAN. While the agonist did not significantly modulate pathogenic cytokine expression, it enhanced the expression of Jun proto-oncogene and Sonic Hedgehog (Shh) mRNA, crucial molecules for peripheral nerve regeneration. Histological analysis revealed increased Shh-positive cells in the nerves of treated rats. These findings suggest that S1Pr5 agonists have the potential to enhance recovery from EAN by promoting nerve regeneration rather than by modulating the inflammatory response. This study provides insights into novel therapeutic approaches for autoimmune peripheral neuropathies, highlighting the role of S1Pr5 in nerve repair processes. Further research is needed to fully elucidate the mechanisms and validate these findings for potential clinical applications.