Ooi Theng Choon, Chan Kok Meng, Sharif Razinah
Biomedical Science Programme, School of Diagnostic and Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300, Kuala Lumpur, Malaysia.
Environmental Health and Industrial Safety Programme, School of Diagnostic and Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300, Kuala Lumpur, Malaysia.
Biol Trace Elem Res. 2016 Aug;172(2):458-464. doi: 10.1007/s12011-015-0615-x. Epub 2016 Jan 9.
This study aimed to investigate the role of the mitogen-activated protein kinases (MAPKs) signaling pathway in the anti-inflammatory effects of zinc carnosine (ZnC) in lipopolysaccharide (LPS)-induced RAW 264.7 cells. Cells were pretreated with ZnC (0-100 μM) for 2 h prior to the addition of LPS (1 μg/ml). Following 24 h of treatment, ZnC was found not to be cytotoxic to RAW 264.7 cells up to the concentration of 100 μM. Our current findings showed that ZnC did not protect RAW 264.7 cells from LPS-induced "respiratory burst". Significant increment in intracellular glutathione (GSH) level and reduction in thiobarbituric acid reactive substances (TBARS) concentration can only be observed in cell pretreated with high doses of ZnC only (50 and 100 μM for GSH and 100 μM only for TBARS). On the other hand, pretreatment of cells with ZnC was able to inhibit LPS-induced inducible nitric oxide synthase and cyclooxygenase-2 expression significantly. Furthermore, results from immunoblotting showed that ZnC was able to suppress nuclear factor-kappaB (NF-κB) activation, and highest suppression can be observed at 100 μM of ZnC pretreatment. However, pretreatment of ZnC did not inhibit the early activation of MAPKs. In conclusion, pretreatment with ZnC was able to inhibit the expression of inflammatory mediators in LPS-induced RAW 264.7 cells, mainly via suppression of NF-κB activation, and is independent of the MAPKs signaling pathway.
本研究旨在探讨丝裂原活化蛋白激酶（MAPKs）信号通路在肌肽锌（ZnC）对脂多糖（LPS）诱导的RAW 264.7细胞抗炎作用中的作用。在添加LPS（1μg/ml）之前，细胞先用ZnC（0 - 100μM）预处理2小时。处理24小时后，发现浓度高达100μM的ZnC对RAW 264.7细胞无细胞毒性。我们目前的研究结果表明，ZnC不能保护RAW 264.7细胞免受LPS诱导的“呼吸爆发”。仅在高剂量ZnC预处理的细胞中（GSH为50和100μM，TBARS仅为100μM）才能观察到细胞内谷胱甘肽（GSH）水平显著升高和硫代巴比妥酸反应性物质（TBARS）浓度降低。另一方面，用ZnC预处理细胞能够显著抑制LPS诱导的诱导型一氧化氮合酶和环氧化酶-2的表达。此外，免疫印迹结果表明，ZnC能够抑制核因子-κB（NF-κB）的激活，在100μM ZnC预处理时观察到最高抑制作用。然而，ZnC预处理并未抑制MAPKs的早期激活。总之，ZnC预处理能够抑制LPS诱导的RAW 264.7细胞中炎症介质的表达，主要是通过抑制NF-κB的激活实现的，且与MAPKs信号通路无关。
