Changes in expression of sodium channel?subunit mRNA in dorsal root ganglion in a rat model of neuropathic pain / 中华麻醉学杂志

ABSTRACT

Objective To examine the changes in the expression of voltage-gated sodium channel?subunit mRNA in the dorsal root ganglion(DRG)and the role it plays in the neuropathie pain.Methods Thirty- two male SD rats weighing 250-400g were randomly divided into 2 groupsgroupⅠneuropathic pain(SNL,n= 20)and groupⅡsham operation(n=12).Neuropathic pain was produced by ligation of right sciatic nerve according to Seltzer.Paw withdrawal latency to noxious thermal(PWHL)and mechanical(PWML)stimulation were measured before(baseline)and 1,2,3,5,8,11,14,28 day after sciatic nerve ligation(SNL).DRG at L_(4,5) was isolated on the 14th day after SNL in 8 SNL and 4 sham-operated animals for determination of sodium channel?subunit mRNA expression(by in-situ hybridization).Results PWHL and PWML were significantly decreased on the 2nd-28th day after SNL as compared to the baseline in SNL group.There was no significant difference in?_1 subunit mRNA expression between the 2 groups.The?_2 subunit mRNA expression in DRG was hardly detectable.The?_3 subunit mRNA expression in DRG on the operated side was significantly higher in SNL group than in sham-operation group.Conclusion The up-regulation of sodium channel?_3 subunit mRNA expression in DRG may play an important role in neuropathic pain.