Herbal Medicine Resources Research Center, Korea Institute of Oriental Medicine, Naju-si, Jeollanam-do 58245, Korea.
Clinical Medicine Division, Korea Institute of Oriental Medicine, Daejeon 34054, Korea.
Int J Mol Sci. 2019 Jul 22;20(14):3574. doi: 10.3390/ijms20143574.
The purpose of the present study was to evaluate the effects of bakuchiol on the inflammatory response and to identify the molecular mechanism of the inflammatory effects in a lipopolysaccharide (LPS)-stimulated BV-2 mouse microglial cell line and mice model. The production of prostaglandin E (PGE), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) was measured by enzyme-linked immunosorbent assay. The mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α, and IL-6 was measured using reverse transcription-polymerase chain reaction analysis. Mitogen-activated protein kinase (MAPK) phosphorylation was determined by western blot analysis. In vitro experiments, bakuchiol significantly suppressed the production of PGE and IL-6 in LPS-stimulated BV-2 cells, without causing cytotoxicity. In parallel, bakuchiol significantly inhibited the LPS-stimulated expression of iNOS, COX-2, and IL-6 in BV-2 cells. However, bakuchiol had no effect on the LPS-stimulated production and mRNA expression of TNF-α or on LPS-stimulated c-Jun NH2-terminal kinase phosphorylation. In contrast, p38 MAPK and extracellular signal-regulated kinase (ERK) phosphorylation were inhibited by bakuchiol. In vivo experiments, Bakuchiol reduced microglial activation in the hippocampus and cortex tissue of LPS-injected mice. Bakuchiol significantly suppressed LPS-injected production of TNF-α and IL-6 in serum. These results indicate that the anti-neuroinflammatory effects of bakuchiol in activated microglia are mainly regulated by the inhibition of the p38 MAPK and ERK pathways. We suggest that bakuchiol may be beneficial for various neuroinflammatory diseases.
本研究旨在评估补骨脂素对炎症反应的影响，并确定其在脂多糖（LPS）刺激的 BV-2 小鼠小胶质细胞系和小鼠模型中炎症作用的分子机制。通过酶联免疫吸附试验测定前列腺素 E（PGE）、肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6）的产生。采用逆转录-聚合酶链反应分析测定诱导型一氧化氮合酶（iNOS）、环氧化酶-2（COX-2）、TNF-α和 IL-6 的 mRNA 表达。通过 Western blot 分析测定丝裂原活化蛋白激酶（MAPK）磷酸化。在体外实验中，补骨脂素显著抑制 LPS 刺激的 BV-2 细胞中 PGE 和 IL-6 的产生，而无细胞毒性。同时，补骨脂素显著抑制 LPS 刺激的 BV-2 细胞中 iNOS、COX-2 和 IL-6 的表达。然而，补骨脂素对 LPS 刺激的 TNF-α产生和 mRNA 表达或 LPS 刺激的 c-Jun NH2-末端激酶磷酸化没有影响。相比之下，p38 MAPK 和细胞外信号调节激酶（ERK）磷酸化被补骨脂素抑制。在体内实验中，补骨脂素减少 LPS 注射小鼠海马和皮质组织中的小胶质细胞活化。补骨脂素显著抑制 LPS 注射产生的 TNF-α和 IL-6 在血清中的表达。这些结果表明，补骨脂素在激活的小胶质细胞中的抗炎作用主要通过抑制 p38 MAPK 和 ERK 通路来调节。我们建议补骨脂素可能对各种神经炎症性疾病有益。
