Department of Optometry, Asia University, Taichung, Taiwan.
Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan.
J Food Drug Anal. 2017 Oct;25(4):908-918. doi: 10.1016/j.jfda.2016.11.018. Epub 2017 Feb 14.
Recent investigations have demonstrated that carotenoid extract of Dunaliella salina alga (Alga) contains abundant β-carotene and has good anti-inflammatory activities. Murine macrophage (RAW264.7 cells) was used to establish as an in vitro model of pseudorabies virus-induced reactive oxygen species (ROS) response. In this study, antioxidant activities of Alga were measured based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, trolox equivalent antioxidant capacity assays, reducing power, and virus-induced ROS formation in RAW264.7 cells. Anti-inflammatory activities of Alga were assessed by its ability to inhibit the production of interleukin-6 and nitric oxide (NO) using enzyme-linked immunosorbent assay, then the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway was investigated by measuring the inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor-κB (p50 and p65), JAK, STAT-1/3, and suppressor of cytokine signaling 3 (SOCS3) by Western blotting. In addition, Alga inhibited virus replication by plaque assay. Our results showed that the Alga had high antioxidant activity, significantly reduced the virus-induced accumulation of ROS, and inhibited the levels of nitric oxide and interleukin-6. Further studies revealed that Alga also downregulated the gene and protein expressions of iNOS, COX-2, nuclear factor-κB (p50 and p65), and the JAK/STAT pathway. The inhibitory effects of Alga were similar to pretreatment with specific inhibitors of JAK and STAT-3 in pseudorabies virus -infected RAW264.7 cells. Alga enhanced the expression of SOCS3 to suppress the activity of the JAK/STAT signaling pathway in pseudorabies virus-infected RAW264.7 cells. In addition, Alga has decreased viral replication (p < 0.005) at an early stage. Therefore, our results demonstrate that Alga inhibits ROS, interleukin6, and nitric oxide production via suppression of the JAK/STAT pathways and enhanced the expression of SOCS3 in virus-infected RAW264.7 cells.
最近的研究表明，盐生杜氏藻（Alga）的类胡萝卜素提取物含有丰富的β-胡萝卜素，具有良好的抗炎活性。鼠巨噬细胞（RAW264.7 细胞）被用于建立伪狂犬病病毒诱导的活性氧（ROS）反应的体外模型。在这项研究中，基于 2,2-二苯基-1-苦基肼（DPPH）自由基清除、trolox 等效抗氧化能力测定、还原能力以及 RAW264.7 细胞中病毒诱导的 ROS 形成，测量了 Alga 的抗氧化活性。通过酶联免疫吸附试验（ELISA）测定 Alga 抑制白细胞介素 6 和一氧化氮（NO）产生的能力，评估了 Alga 的抗炎活性，然后通过测量诱导型一氧化氮合酶（iNOS）、环氧化酶-2（COX-2）、核因子-κB（p50 和 p65）、JAK、STAT-1/3 和细胞因子信号转导抑制因子 3（SOCS3），研究了 Janus 激酶/信号转导和转录激活因子（JAK/STAT）途径，通过 Western blot。此外，Alga 通过噬斑试验抑制病毒复制。我们的结果表明，Alga 具有较高的抗氧化活性，显著减少了病毒诱导的 ROS 积累，并抑制了一氧化氮和白细胞介素 6 的水平。进一步的研究表明，Alga 还下调了 iNOS、COX-2、核因子-κB（p50 和 p65）和 JAK/STAT 途径的基因和蛋白表达。Alga 在伪狂犬病病毒感染的 RAW264.7 细胞中的作用类似于 JAK 和 STAT-3 特异性抑制剂预处理。Alga 通过增强 SOCS3 的表达来抑制 JAK/STAT 信号通路在伪狂犬病病毒感染的 RAW264.7 细胞中的活性。此外，Alga 在早期阶段减少了病毒复制（p<0.005）。因此，我们的研究结果表明，Alga 通过抑制 JAK/STAT 途径抑制 ROS、白细胞介素 6 和一氧化氮的产生，并增强病毒感染的 RAW264.7 细胞中 SOCS3 的表达。
