| 摘要: | 發炎性大腸症（inflammatory bowel disease, IBD）為人類相當重要的腸胃道疾病。目前對於發炎性大腸症的致病機轉仍是不清楚，但有些報告指出proinflammatory cytokine基因的表現，包括 Interleukin -1β、Interleukin -6、Interleukin -4、tumor necrosis factor -α和interferon-γ，可能與發炎性大腸症的發炎有關，而這些proinflammatory cytokine基因的表現主要是由Nuclear factor-kappa B (NF-κB)調控的。所以抑制NF-κB的活性對於發炎性大腸症病患的治療上，也許是一個相當不錯的標的。香草醛(vanillin)為天然香草的化合物，主要作為香料而廣泛地運用在食品及化妝產品上。有文獻指出vanillin具有抗微生物及抗發炎的功能，並且可大量使用在食品的防腐及藥物運用上。因此，本研究利用trinitrobenzene sulfonic acid（TNBS）誘發老鼠的發炎性大腸症，探討香草醛預防及治療發炎性大腸症的效果。將不同濃度的TNBS直接灌入老鼠直腸內，於一天後剖檢進行肉眼及顯微病兆的檢查，結果發現隨著TNBS濃度的上升病兆指數也隨之上升，顯示TNBS確實可以誘發發炎性大腸症的發生。進一步將vanillin於TNBS誘發前、誘發中或誘發後再灌入老鼠直腸內，於不同時間剖檢分析，發現vanillin可以明顯地降低病兆指數，而且大腸重量也隨之下降，但老鼠體重不受影響。因此，這些結果顯示vanillin具有預防及治療發炎性大腸症的潛能。藉由reverse transcription polymerase chain reaction分析vanillin的作用機轉，發現vanillin可以改變Interleukin -1β、Interleukin -6、Interleukin -4、tumor necrosis factor -α和interferon-γ的表現，因為這些cytokine的表現主要受到NF-κB的調控。因此，我們藉由electrophoretic mobility shift assay及西方轉漬法分析vanillin是否會干擾NF-κB活性。結果顯示vanillin可以藉由抑制p65移動至細胞核內，而抑制TNBS所誘發的NF-κB的活性。我們進ㄧ步利用活體影像分子系統分析vanillin治療發炎性大腸症的效果。將vanillin於TNBS誘發後注入帶有NF-κB/luciferase的基因轉殖鼠的直腸內，再將luciferin以腹腔注射的方式注入老鼠腹腔內，利用活體冷光儀分析，發現vanillin抑制NF-κB活性導致降低luciferase的活性。綜合以上結果，vanillin可以藉由NF-κB訊息傳導路徑抑制cytokine的表現，而達到預防及治療發炎性大腸症的效果。
The inflammatory bowel diseases (IBD) is recognized as an important gastrointestinal diseases in children and adults. Pathogenesis of IBD is ambiguous. The expressions of proinflammatory cytokine genes, including interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, IL-4 and interferon (IFN)-γ, might be involved in the pathogenesis of IBD. Since the expression of cytokine gene is mainly regulated by the transcription factor nuclear factor-κB (NF-κB), the NF-κB might be the target for the development of anti-IBD drugs. Vanillin is a widely used flavor compound in food and cosmetics, with an estimated annual worldwide consumption of over 2000 tons. Moreover, vanillin displays antimicrobial and anti-inflammatory properties, and is used as a food preservative and for medicinal purposes. This study therefore investigated the preventive and therapeutic effects of vanillin on trinitrobenzene sulfonic acid（TNBS）-induced colitis in mice. TNBS induced colitis in mice in a dose-dependant manner. However, the administration of vanillin before, during, or after TNBS induction decreased the macroscopic and microscopic scores of IBD. The TNBS-induced colon weight was also decreased by vanillin treatment. Vanillin down-regulated the TNBS-induced expression of IL-1β, IL-6, TNF-α, IL-4 and IFN-γ by reverse transcription polymerase chain reaction. Moreover, vanillin inhibited NF-κB activity via suppressing p65 translocation to nuclear. Furthermore, the in vivo imaging also showed that vanillin inhibited NF-κB activity, resulted in the decrease of luciferase activity in transgenic mice. Taken together, vanillin might be the potential compound for the treatment and preventive of IBD. |
