Basic Research of Gene Therapy for Intractable Pain with siRNA

为了研究BDNF的哪个外显子与炎性疼痛有关，我们对大鼠背根神经节中信息诱导的BDNF外显子的表达进行了定量。将完全弗氏佐剂(CFA)皮下注射至大鼠左后爪足底表面。CFA处理组大鼠同侧背根神经节外显子I的表达显著增加。我们的结果支持炎症增加了总的BDNF mRNA。此外，我们的结果表明，外显子I在炎症后BDNF mRNA的增加中起着重要作用，因此，我们以BDNF的外显子I为靶点，用siRNA下调BDNF的表达。我们为BDNF的Exson I创建了两个不同的siRNA。在注射CFA前10天置入鞘内导管。在注射CFA前，BDNF外显子I上的两个不同的siRNAs可以减轻小鼠的疼痛行为，但不能完全抑制。应用两种siRNA后，DRG中BDNF的表达并未完全被抑制，未来我们还需要研究应该给予多少剂量的siRNA。我们还必须检查何时应该注射siRNA。

To investigate which exon of BDNF is involved in inflammatory pain, we quantitated infIammation-induced expression of BDNF exons in the rat DRG. Rats received subcutaneous injections of complete Freund's adjuvant (CFA) into plantar surface of the left hind paw. InCFA-treated rats, the expressions of exon I in ipsilateral DRGincreased significantly. Our results support that inflammation increases total BDNF mRNA. Furthermore, our results indicate that exon I plays important role in increase in BDNF mRNA after inflammation.Therefore, we targeted the exon I of BDNF for knock-down with siRNA. We created the two different siRNAs for exson I of BDNF. The intrathecal catheter was inserted 10 days before CFA injection. The two different siRNAs for the exon I of BDNF twice before CFA injection.The pain behaviors were decreased by the administration of siRNAs, but not completed suppressed. The expression of BDNF was not completed suppressed in DRG after the administration of the two siRNAs.In the future, We have to investigate how much doses of siRNA should be administered. We also have to check the timing when siRNA should be administerd.