Effect Of Triptolide On Analgesic And The Neural Biology Mechanism Of Analgesic In Spinal Cord Of Rats With Adjuvant Arthritis

Objective：To study the effect of Triptolide(TP) on analgesic and expression of inducible nitricoxide synthase(iNOS),substance P(SP), interleukin-1β(IL-1β), tumour necrosis factor-α(TNF-α),Bandeiraea simplicifolia isolectin-B4(BSI-B4) binding sites and N-methyl-D-aspartate receptor subtypeR1(NMDAR1)in spinal dorsal horn and dorsal root ganglion(DRG) of rats with adjuvant arthritis in thehigh, middle and low dose groups of TP.To explore the possible mechanism of TP on analgesic of rats withadjuvant arthritis.Methods: Fifty healthy SD rats were randomly divided into normal group (group A), model group(group B), low(group C), middle (group D), high(group E) dose treatment group with TP. Except the groupA, each group of rats right rear toe injection of0.1ml freund’s complete adjuvant to establish model of AA.Rats in the C, D and E group were taken different doses (0.1mg/kg group C, group D0.2mg/kg,0.4mg/kggroup E) by intraperitoneal injection of TP for9days，and then thermal withdrawal latency,50%mechanical withdraw threshold(MWT), edema rate(ER%)and the expression of iNOS, SP, IL-1β,TNF-α,NMDAR1,and BSI-B4binding sites in lumbar5(L5) spinal dorsal horn and DRG were detected,and study on detection mRNA of iNOS、SP、IL-1β、TNF-α by RT-PCR.Results:50%MWT and Thermal withdrawal latency of rats in group B was significantly lower thanthat of group A(P<0.01) in14days after modeling. group C, D and E was significantly higher than that ofgroup B(P<0.01) in23days after modeling, TP increased the MWT and Thermal withdrawal latency by aquantity-effect relationship; ER%of rats in group B was significantly higher than that of group A(P<0.01)in14days after modeling, group C, D and E was significantly lower than that of group B(P<0.01) in23days after modeling. Results of immunochemistry analysis showed that iNOS、SP、IL-1β、TNF-α、NMDAR1and BSI-B4binding sites expression levels were significantly increased in group B than groupA(P<0.01); group C, D and E was significantly higher than that of group B(P<0.01)by a quantity-effectrelationship. RT-PCR results showed that: iNOSmRNA、SPmRNA、IL-1βmRNA、TNF-αmRNA expressionlevels were significantly increased in group B than those in group A(P<0.01); iNOSmRNA、SPmRNA、IL-1βmRNA expression levels in group C, D and E was significantly higher than those of groupB(P<0.01),TNF-αmRNA level of group C and group B there was no significant difference,TNF-αmRNAexpression levels in group D and E was significantly higher than that of group B(P<0.01).Conclusion: Effect of TP on analgesic is involved to reduce significantly levels of expression ofiNOS、SP、IL-1β、TNF-α、NMDAR1and BSI-B4binding sites in spinal dorsal horn and DRG in rats withadjuvant arthritis. This may be one of the mechanism of TP on analgesic of rats with adjuvant arthritis.