内源性神经生长因子在大鼠炎性痛中的作用及其机制

目的：探讨神经生长因子（nerve growth factor,NGF）在大鼠炎性痛中的作用及其机制。方法：将雌性SD大鼠50只,随机分为5组（每组10只）,I组为模型对照组,Ⅱ组为炎性痛组,Ⅲ组为模型对照组＋NGF中和抗体,Ⅳ组为炎性痛组＋IgG对照抗体;V组为炎性痛组＋NGF中和抗体。造模后第1～第3天,鞘内分别注射NGF中和抗体或IgG对照抗体,每天1次,剂量20μg/10μL。分别于造模前及造模后隔日开始测定大鼠热缩足反射潜伏期（PWTL）;并于第1天注药后连续测定24 h。造模后第3天测痛后（最后一次注药后3 h）处死大鼠,测定脊髓NGF的蛋白表达水平（荧光免疫组化和Western-Blot）。结果：造模后第1～第14天,与I组比较,Ⅱ组、Ⅳ组PWTL值显著下降;造模后第3天,NGF的平均光密度值（IOD）及蛋白表达显著增加,差异均有统计学意义（均P〈0.01）;Ⅲ组上述指标（包括PWTL和IOD及蛋白表达）与I组比差异无统计学意义（P〉0.05）;与Ⅱ组、Ⅳ组比较,V组PWTL值显著增高,脊髓部位的NGF表达显著减少,差异均有统计学意义（均P〈0.01）。结论：内源性NGF可能参与了炎性痛大鼠痛觉过敏的形成。

The role of endogenous nerve growth factor in pain facilitation and spinal mechanism in rat model of inflammatory pain

Objective: To investigate the role of neurotrophic factor(NGF)in pain facilitation and its mechanisms in the rat model of inflammatory pain.Methods: Fifty SD female rats were divided into 5 groups(n =10 in each) randomly:group I:control group(sham operation);groupⅡ:model group;group Ⅲ:control group+anti-NGF intrathecal(i.t.);group Ⅳ:model group+control IgG i.t.;group V :model group+anti-NGF i.t..Anti-NGF or control IgG was injected i.t.during 1 to 3th day.Paw withdrawal thermal latency(PWTL) was measured one day before model injection and every 2 days after model injection.On the 3th day after i.t.injection of either anti-NGF or control IgG,rats were sacrificed after threshold tested,the lumbar 4-6 spinal cord were removed.The expression of NGF was detected by immunohistochemistry assay and Western-Blot.Results: From the 1 to 14th day after operation,PWTL threshold in groups Ⅱ and Ⅳ was significantly lower than that in group I and group V(P <0.01),group V was remarkly higher than that in group Ⅳ(P <0.01).The NGF expression in groupⅡor Ⅳ were significantly increased compared with that in group I or V(P <0.01),intrathecal anti-NGF was significantly suppressed the protein expression of NGF(P <0.01).Conclusion: NGF maybe involved in the inflammatory pain.