IL-6 up-regulates CNTF mRNA expression and enhances neurite regeneration

Interleukin-6 (IL-6) is a neurotrophic cytokine, however, its direct effect on nerve regeneration has not been well characterized. We therefore examin ed the effect of IL-6 on neurite regeneration using the rat dorsal root gan glion. IL-6 significantly enhanced neurite regeneration from transected ner ve terminals. We also examined the mRNA expression of IL-6 family cytokines and their receptors during the regeneration. The mRNA expressions of IL-6, IL-6 receptor, leukemia inhibitory factor (LIF), ciliary neurotrophic fact or (CNTF) receptor alpha, and LIF receptor beta showed no significant diffe rences by the addition of IL-6. In contrast, IL-6 enhanced the mRNA express ion of gp 130 and CNTF. In addition, CNTF significantly increased neurite r egeneration when added exogenously. Our data suggest that IL-6 enhanced reg eneration via up-regulating CNTF expression. NeuroReport 12:1081-1085 (C) 2 001 Lippincott Williams & Wilkins.