Analgesic Effect Of Sulfasalazine On Neuropathic Pain In Rats

Objective: To explore the effect of sulfasalazine(SFZ)on neuropathic pain caused by chronic constriction injury(CCI)of sciatic nerve in rats,the expression of inflammatory cytokines(TNF-α、IL-1βand IL-6)and activation of spinal glial cells in dorsal horn of spinal cord.Methods: SD rats were randomly divided into 3 groups(Sham group,CCI group and SFZ group).CCI was used to build neuropathic pain model.The rats were given 65 mg·kg-1 SFZ by intragastric administration at a volume 1ml/100 g body weight.Mechanical withdrawal threshold was measured by von Frey filaments.The expression levels of Iba-1 and GFAP in spinal cord of rats were detected by Western blotting and immunofluorescent staining.Cellular localization of NF-κB p65 was performed by immunofluorescence staining.NF-κB p65 and NF-κB p50 were detected by Western Blot.The effect of SFZ administration on m RNA expression of TNF-α 、 IL-1β and IL-6 was analyzed by real-time q PCR.Results: The MWT value of CCI group was significantly lower than that of Sham group(P<0.05);The MWT value of SFZ group was significantly higher than that of CCI group(P<0.05).The expression levels of Iba-1 and GFAP in CCI group was significantly higher than that in Sham group(P<0.05);The expression level of Iba-1 in SFZ group was not significantly different from that in CCI group(P>0.05);Theexpression of GFAP in SFZ group was lower than that in CCI group.(P<0.05).NF-κB p65 is mainly expressed in neurons and astrocytes of the spinal dorsal horn.SFZ can reduce the increase of NF-κ B p65 induced by CCI(P<0.05).The levels of TNF-α、IL-1β and IL-6 m RNA in CCI group were significantly higher than those in Sham group(P<0.05);The TNF-α 、 IL-1β and IL-6 m RNA levels in SFZ group were significantly lower than those in CCI group(P<0.05).Conclusion: SFZ may attenuate CCI-induced neuropathic pain by inhibiting the activation of spinal astrocytes and the production of TNF-α,IL-1β,and IL-6.