Kobayashi Hiroyuki, Yokoyama Masataka, Matsuoka Yoshikazu, Omori Megumi, Itano Yoshitaro, Kaku Rhuji, Morita Kiyoshi, Ichikawa Hiroyuki
Department of Anesthesiology and Resuscitology, Okayama University Graduate School Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Okayama City 700-8558, Japan.
Brain Res. 2008 Apr 24;1206:13-9. doi: 10.1016/j.brainres.2007.12.004. Epub 2007 Dec 8.
Brain-derived neurotrophic factor (BDNF) expression changes in the dorsal root ganglion (DRG) and spinal cord in some pain models. Recently, rat BDNF transcripts containing novel 5' untranslated exons were identified and characterized, and a new numbering system for rat BDNF exons was introduced. We examined the expression profiles of these novel BDNF transcripts in bilateral L4/5 DRGs in an L5-selective spinal nerve ligation (SSNL) model and bilateral L5 DRGs in a complete Freund's adjuvant (CFA) model of rats. L5SSNL increased significantly (P<0.05) the expression of total BDNF mRNA and exon I, IIA, IIB, IIC, III, IV, VI, and IXA transcripts in ipsilateral L4 DRG. Although expression of total BDNF mRNA remained unchanged in ipsilateral L5 DRG in the L5SSNL model, expression of exon I transcript increased significantly (P<0.05) and that of exon IV transcript decreased significantly (P<0.05). The expression profiles of the variant exons in ipsilateral L4 DRG of the L5SSNL model were quite similar to those in ipsilateral DRG of the CFA model, and exon I transcript was the most common BDNF mRNA in these DRGs. Although L5SSNL increased significantly (P<0.05) the expression of total BDNF mRNA and exon IIC and IXA transcripts in the contralateral L4/5 DRGs, CFA treatment did not alter the expression of total BDNF mRNA or specific transcripts in the contralateral DRGs. These findings suggest that exon I plays an important role in the increase in BDNF expression in ipsilateral DRGs regardless of condition.
在一些疼痛模型中，脑源性神经营养因子（BDNF）在背根神经节（DRG）和脊髓中的表达会发生变化。最近，含有新的5'非翻译外显子的大鼠BDNF转录本被鉴定和表征，并引入了大鼠BDNF外显子的新编号系统。我们在大鼠的L5选择性脊神经结扎（SSNL）模型中检测了双侧L4/5 DRG中这些新的BDNF转录本的表达谱，以及在完全弗氏佐剂（CFA）模型中双侧L5 DRG中这些新的BDNF转录本的表达谱。L5 SSNL使同侧L4 DRG中总BDNF mRNA以及外显子I、IIA、IIB、IIC、III、IV、VI和IXA转录本的表达显著增加（P<0.05）。尽管在L5 SSNL模型中同侧L5 DRG中总BDNF mRNA的表达保持不变，但外显子I转录本的表达显著增加（P<0.05），而外显子IV转录本的表达显著降低（P<0.05）。L5 SSNL模型中同侧L4 DRG中可变外显子的表达谱与CFA模型同侧DRG中的表达谱非常相似，并且外显子I转录本是这些DRG中最常见的BDNF mRNA。尽管L5 SSNL使对侧L4/5 DRG中总BDNF mRNA以及外显子IIC和IXA转录本的表达显著增加（P<0.05），但CFA处理并未改变对侧DRG中总BDNF mRNA或特定转录本的表达。这些发现表明，无论何种情况，外显子I在同侧DRG中BDNF表达增加中起重要作用。
