不同丘脑核团毁损镇痛效果的实验研究

Comparison of analgesic effect following different thalamotomy in the rat formalin test

目的比较大鼠不同丘脑核团毁损的镇痛效果，为临床上核团毁损治疗顽固性疼痛靶点的选择提供实验依据。方法大鼠30只，分为假损伤组（Sham）及丘脑中央中核（CM）、丘脑束旁核（PF）、丘脑腹后外侧核（VPL）、丘脑中央中核加扣带回毁损组（CM＋cg），将2μl 10％苯酚／甘油立体定向注至相应核团进行毁损。测量福尔马林诱导的动物舔咬时间、挠曲时间、以及畏缩次数。结果各毁损组动物舔咬时间较Sham组明显缩短（P〈0．01），而挠曲时间及畏缩次数只有轻微差异。此外，VPL组动物舔咬时间比CM组和CM＋cg组为短（P〈0．05），而CM组和CM＋cg组间行为痛反应差异无统计学意义（P〉0．05）。结论CM、PF、VPL、CM＋cg毁损后急性期，毁损CM、PF、VPL、CM＋cg都能提高大鼠的痛阈，其中以VPL组最明显。大鼠由脊髓上神经中枢调控的行为痛反应均明显减少，其中以VPL组最明显。CM＋cg双核团毁损的镇痛效果并未明显优于CM单一核团毁损。

Objective To compare with the analgesic effect following different thalamotomy in rats, for provided an index of ablative targets for clinical application. Methods 30 rats were randomly divided into sham and 4 thalamotomy groups： central medial thalamic nucleus （CM）, parafascicular thalamic nucleus （PF）, ventral posterolateral thalamic nucleus （VPL）, and CM ＋ Cigulum （cg）. 2μl 10% concentration of phenol dissolved in glycerin were used for stereotactic thalamotomy. The formalin test was carried out in an open field apparatus where the animal＇s formalin-induced responses （licking duration, flexing duration, and flinching frequency of the injected paw） were recorded for 60 min. Results Significant of the factor thalamotomy were found due to the four ablative groups showing shorter licking than sham （ P 〈 0. 01 ）, Whereas flexing duration and flinching frequency were only slightly affected by thalamotomy. Moreover, licking duration was lower in VPL group than in CM and CM ＋ cg groups （P 〈0.05 ）, whereas nociceptive responses did not differ between the CM and CM ＋ cg groups （P 〉 0.05 ）. Conclusion In acute period, CM, PF, VPL, CM ＋ cg ablation all showed to reduce the pain-induced behavioral responses related to supraspinal neural circuits （ licking of the injected paw ）, among which damage of VPL might be most active. CM ＋ cg damage did not get better antinociceptive effect than single CM ablation.