| 摘要: | 先前已有研究證實紅果釣樟 (Lindera erythrocarpa Makino) 的果實抽出物及其主成分Lucidone在體內和體外實驗中具有很好的抗發炎活性。在RAW264.7細胞株實驗中，紅果釣樟果實可以顯著地抑制脂多醣體（Lipopolysaccharide, LPS）所誘導一氧化氮（Nitric Oxide, NO）的產生；此外研究亦證實iNOS和COX-2的蛋白表現量也會隨Lucidone的劑量增加而被抑制。
本研究主要想探討Lucidone對人類皮膚細胞株HaCaT抗發炎的影響。因此本實驗想探討Lucidone是否可以減少水溶性自由基產生者AAPH對人類皮膚細胞株HaCaT所造成的傷害。實驗給予Lucidone不同濃度24小時後再給予AAPH（30 mM）處理4~6小時，細胞存活率顯示隨著Lucidone濃度的增加，可以減少AAPH對人類皮膚細胞株HaCaT的傷害。另外，AAPH會促進細胞內ROS量的增加，而Lucidone也可以很顯著地抑制細胞內ROS的產生。隨著給予AAPH的時間增加，COX-2蛋白的表現量也隨之增加；而有給予不同濃度Lucidone保護後的HaCaT細胞，可以顯著地抑制AAPH所誘導的COX-2和iNOS蛋白表現。接著以酵素免疫分析法來觀察 PGE2的結果顯示，Lucidone可以顯著地減少因AAPH所誘導的PGE2分泌。另外，在MAPKs訊息途徑方面，Lucidone也可以減少磷酸化蛋白(p-ERK1/2、p-p38、p-JNK1/2)的表現。然而，在MAPKs抑制劑結果上，顯示可能不是經JNK路徑而抑制COX-2的表現。而隨著Lucidone濃度的增加，可以增加IκBα的穩定性，預防其泛素化而被降解。
本研究的另一個目的想探討Lucidone在皮膚損傷癒合的機轉。結果顯示低濃度的Lucidone有促進HaCaT細胞增生的效果，且會經由MAPK訊息途徑促進HaCaT細胞的移行現象，進而促成皮膚損傷的癒合。在皮膚中，包括組織傷害、腫瘤形成、血管新生、細胞凋亡和發炎等都會使許多基質金屬蛋白酶（MMPs）表現。MMP-9已經被證實和皮膚真皮層的疾病及一般損傷癒合（wound healing）有關。本實驗結果顯示Lucidone促進皮膚細胞的癒合可能是藉由增加MMP-9、減少TIMP-2蛋白的表現，而促進細胞的遷移（migration）作用。
總結上述結果，Lucidone抑制發炎反應相關的ROS產生、PGE2分泌和COX-2及iNOS蛋白表現是經由抑制MAPKs訊息傳遞路徑中ERK、p38蛋白的磷酸化進而增加IκBα的穩定性最後減少皮膚的發炎反應；而HaCaT細胞中促進損傷癒合的過程是經由調節MAPKs訊息途徑及相關的MMP-9蛋白表現進而促成細胞遷移而達到皮膚損傷癒合的效果。
The anti-inflammatory activities of lucidone isolated from the fruits of Lindera erythrocarpa Makino in an in vivo and in vitro were investigated. Lindera erythrocarpa fruits inhibited significantly nitric oxide (NO) production in lipopolysaccharide (LPS) induced NO in the murine macrophage cell line (RAW264.7) assay. Futhermore, lucidone suppressed iNOS and COX-2 protein expression in a dose-dependent manner.
In this study, we here investigate the effect of lucidone on AAPH-induced oxidative stress in human keratinocyte (HaCaT) cell. Our data indicate that pretreatment of HaCaT cells with different concentration of lucidone inhibited AAPH (30mM)-mediated decrease in cell viability. In addition, AAPH is a potent inducer of reactive oxygen species (ROS), which can induce oxidative stress and cellular damage, including inflammatory response; whereas lucidone reduced AAPH-induced ROS generation in a dose-dependent manner. Moreover, a marked increase in COX-2 protein expression was observed 4~6 h after treating with 30 mM of AAPH. Lucidone also reduced the COX-2 and iNOS protein expression after AAPH treated in a dose-dependent manner. Additionally, examing the human PGE2 immunoassay kit, suggesting that AAPH-induced PGE2 production was inhibited by lucidone significantly. On the other hands, lucidone diminished AAPH-induced MAPKs signaling pathway activation (phosphorylation of ERK, p38 and JNK). However, the results of MAPKs inhibitor suggest that lucidone possibly not though JNK pathway inhibited AAPH-induced COX-2 expression. Besides, lucidone caused a dose-dependent enhancement of IκBα protein stability, prevention of its proteolytic degradation.
On the other side, the purpose of this study was to investigate the effect of lucidone on wound healing and its underlying mechanism. Our result demonstrated that a low dose of lucidone enhanced the proliferation and facilitated the migration of HaCaT cells through different MAPK signaling pathways, and accelerated scrape-wound healing in vitro. In the skin, expression of several matrix metalloproteinases (MMPs) occurs in response to tissue injury, tumorigenesis, angiogenesis, apoptosis and inflammation. MMP-9 has been reported to be implicated in both dermail diseases and normal wound healing. Our results demonstrate that lucidone-mediated migration and wound healing were increased MMP-9, inhibited TIMP-1 protein expression in HaCaT cells.
Taken together, lucidone inhibited pro-inflammatory mediators ROS generation, PGE2 production and COX-2, iNOS protein expression through regulation MAPKs family of ERK and p38 phosphorylation and promotes IκBα protein stability to reduce inflammatory responses in skin. Lucidone possesses a therapeutic effect in the wound healing process by regulating MAPKs signaling cascade and MMP-9 protein expression in human keratinocyte HaCaT cells. |
