Study On The Analgesic Effect Of Different Moxibustion Temperature And The Molecular Response Of DRG Pain Signal

Objective:To investigate the analgesic effect of moxibustion with different moxibustion temperature on chronic inflammatory pain and neuropathic pain and explore the molecular response of DRG analgesia signal caused by different moxibustion temperature.Methods:Dressing by screening basic pain threshold,healthy adult C57BL/6J mice were randomly divided into chronic inflammatory pain group and neuropathic pain group.The former was randomly divided into the following six subgroups: control group,CFA-model group,CFA-moxi-37?group,CFA-moxi-42?group,CFA-moxi-47?group and CFA-moxi-52?group.And the latter had control(sham operation)group,SNI-model group,SNI-moxi-37 ? group,SNI-moxi-42 ? group,SNI-moxi-47 ?group and SNI-moxi-52? group.Injected with complete Freund's adjuvant(20ul sigma)to the right hind paw for inducing inflammatory pain.Neuropathic pain model was established by spared nerve injury(SNI).Every moxibustion groups were given moxibustion intervention 30 min with different moxibustion temperature.The moxibustion temperature of ST36 was monitored by an digital thermodetector and stabilized at 37±1?,42 ± 1?,47 ± 1? and 52 ± 1?.Pain threshold were tested on day1 before modeling,on day 5 before moxibustion intervention and at the 0min,30 min,60 min,90 min,120 min after moxibustion intervention.PCR-array technique was used to detect the expression of 84 related signal molecules in the dorsal root ganglion(DRG)pain pathway in chronic inflammatory pain mice.Statistic analysis was performed with the software 21.0 and figures were made by Graph Pad Prism 6.0.Results:1.The analgesic effect of different moxibustion temperature on chronic inflammatory pain.While after CFA injection,the average of thermal withdrawal latency(TWL)in CFA group and moxibustion groups were decreased remarkably(P<0.05).Compared with model group,after intervention,all the four moxibustion groups demonstrated aclear evidence of TWL increasing(P < 0.05)at 30 min,60min,90 min after moxibustion,and all TWL arrived their peaks at 30 min after moxibustion.Compared between different moxibustion temperature groups,the results displayed an obvious temperature dependent TWL increasing pattern(TWL:CFA-moxi-37 ? <CFA-moxi-42?<CFA-moxi-47?<CFA-moxi-52?)from 0min to 120min(P<0.05,except between CFA-moxi-37? and CFA-moxi-42? group)and moreover the TWL in CFA-moxi-52 ? group was especially higher(P < 0.05)than other three moxibustion groups,even at 120 min after moxibustion(P<0.05).2.The analgesic effect of different moxibustion temperature on neuropathic pain.While after SNI surgery,the average of mechanical withdrawal threshold(MWT)in model group was decreased distinctly(P<0.05).Compared with model group,the MWT were significantly increased in four moxibustion intervention groups(P<0.05)and all have their peaked at 90 min after moxibustion.However,compared between different moxibustion temperature groups,there is no obviously moxibustion temperature dependent MWT increasing pattern displayed.It only,at 60 min after moxibustion,could be seen the trend that higher moxibustion temperature,the more higher MWT.At 90 min,120min after moxibustion,the MWT of 47 ? and 52 ?moxibustion groups were obviously higher than 37? and 42? moxibustion groups(P < 0.05),but there was no statistically significant difference between 52 ? and47? group(P > 0.05).3.The results of changes in pain-related molecules in the DRGCompared with the CFA-moxi-37 ? group,there were up-regulated 35genes(such as Scn10 a,Cd4,Oprd1,P2ry1,Oprk1)and 8 genes were down-regulated(such as Cck,Cckbr,Grm1,Grm5,Ptgs2)in CFA-moxi-42 ? group;there were up-regulated 8 genes(such as Scn10 a,Tlr4,Tlr2,Oprm1,Pla2g1b)and 10 genes was down-regulated(such as Cck,Grm1,Tacr1,Cx3cr1,Pnoc)in CFA-moxi-47 ?group;there were up-regulated 1 genes(Pla2g1b)and 56 genes was down-regulated(such as Comt,Cx3cr1,Ptger4,Cck,Ptges)in CFA-moxi-52?group.Conclusions:1.Moxibustion has significant analgesic effect on inflammatory pain and neuropathic pain.2.On different pain model,peak period of the onset time of moxibustion and the temperature-analgesia effect mode with diverse temperature are different.For inflammatory pain,all pain threshould arrive their peaks at 30 min after moxibustion and display the temperature-dependent mode.As to neuropathic pain,all pain threshould arrive their peaks at 90 min after moxibustion and the temperature-dependent mode is not showed.3.Different moxibustion temperature affected the expression of different analgesic signal molecules,and the expression levels of common signaling molecules are different.The higher the temperature,the more reduce response to pain signaling molecules.Among them,CCK,Grm5 and Pdyn genes may be the key molecules involved in different moxibustion temperature mediated different moxibustion effects.