人神经生长因子β基因转染对神经病理性痛大鼠脊髓背角致痛物质含量的影响

目的 探讨人神经生长因子β(hNGFβ)基因转染对神经病理性痛大鼠脊髓背角降钙素基因相关肽(CGRP)和P物质(SP)含量的影响.方法 雄性SD大鼠48只,体重200～250 g,随机分为3组(n=16):假手术组(Ⅰ组)假手术后立即鞘内注射人工脑脊液;Ⅱ组和Ⅲ组制备坐骨神经慢性压迫性损伤(CCI)模型,术后分别立即鞘内注射人工脑脊液或重组腺病毒介导入神经生长因子β(Ad-hNGFβ)基因.于术前1 d、转染后28 d内每4天测定热痛阈、机械痛阈及行为学评分.每组分别于转染后4、7、14及28 d各处死4只大鼠,取脊髓组织,采用免疫组织化学法测定SP和CGRP含量.结果 与Ⅰ组比较,Ⅱ组和Ⅲ组行为学评分升高,机械痛阈及热痛阈均降低(P<0.01);与Ⅱ组比较,Ⅲ组行为学评分及机械痛阈差异无统计学意义(P>0.05),转染后8～24 d热痛阈升高(P<0.05).术后Ⅱ组和Ⅲ组术侧脊髓背角SP及CGRP含量明显高于Ⅰ组,术后7～28 dm组术侧脊髓背角SP及CGRP含量明显低于Ⅱ组(P<0.05或0.01).结论 Ad-hNGFβ基因转染可能通过降低脊髓背角SP及CGRP含量减轻神经病理性痛大鼠的热痛觉过敏.

Effects of transfection of human beta-nerve growth factor gene on substance P and calcitonin gene-related peptide content of the spinal cord in a rat model of neuropathic pain

Objective To investigate the effects of adenovirus containing human beta-nerve growth factor (Ad-hNGFβ) gene on substance P (SP) and calcitonin gene-related peptide (CGRP) content of the spinal cord in a rat model of neuropathic pain by chronic constrictive injury (CCI). Methods Forty-eight male SD rats weighing 200-250 g were randomly divided into 3 groups (n=16 each) : group Ⅰ sham operation; group Ⅱ CCI and group Ⅲ CCI + Ad-hNGFβ gene IT. The animals were anesthetized with intraperitoneal choral hydrate 300-350 mg/kg. The right sciatic nerve was exposed and 4 ligatures were placed on the sciatic nerve at 1-2 nun intervals as described by Bennet and Xie5]. In sham operation group, right sciatic nerve was exposed but not ligated. In group Ⅰ and Ⅱ artificial cerebrnspinal fluid was injected IT instead of Ad-hNGFβ gene. The behavior score and the paw-withdrawal latency (PWL) to radiant heat and mechanical stimulus were measured one day before operation and every 4 days within the 28 days after gene transfection. Four animals were killed at 4, 7, 14 and 28 day after IT gene transfection in each group and lumbar segment (L4-6 ) of the spinal cord was removed for determination of SP and CGRP content by immunohistochemistry. Results The behavior scores were significantly higher and PWL to radiant heat and mechanical stimulus were significantly lower in group Ⅱ and Ⅲ than in group Ⅰ. There was no significant difference in the behavior score and PWL to mechanical stimulus between group Ⅱ and Ⅲ while the PWL to radiant heat was significantly higher in group Ⅲ than in group Ⅱ. After operation SP and CGRP content were significantly higher in group Ⅱ and group Ⅲ than in group Ⅰ , and significangly lower in group Ⅲ than in group Ⅱ 7-28 days after operation. Conclusion The recomhinant Ad-hNGFβ gene transfection can attenuate heat hyperalgesia by reducing SP and CGRP content of the spinal cord in a rat model of neuropathic pain induced by CCI.