Chondroitin sulfate attenuates formalin-induced persistent tactile allodynia

We examined the effect of chondroitin sulfate (cs),a compound used in the treatment of osteoarthritis and joint pain,on the formalin-induced tactile allodynia in mice. a repeated oral administration of cs (300 mg/kg,b.i.d.) significantly ameliorated the formalin-induced tactile allodynia from day 10 after formalin injection. on day 14,the phosphorylation of spinal p38 mapk and subsequent increase in c-fos-immunoreactive dorsal lumbar neurons were attenuated by the repeated administration of cs. these findings suggest that cs attenuates formalin-induced tactile allodynia through the inhibition of p38 mapk phosphorylation and subsequent up-regulation of c-fos expression in the dorsal lumbar spinal cord. © 2016 the authors