Anti-inflammatory effects of 6S-5-methyltetrahydrofolate-calcium on RAW264.7 cells and zebrafish

Aim: 6S-5-methyltetrahydrofolate is the predominant form of dietary folate in circulation and is used as a crystalline form of calcium salt (MTHF-Ca). Reports revealed that MTHF-Ca was more safe than folic acid, a synthetic and highly stable version of folate. Folic acid has been reported to have anti-inflammatory effects. The study's objective was to assess the anti-inflammatory effect of MTHF-Ca in vitro and in vivo.Main methods: In vitro, the ROS production was assessed by H2DCFDA, and nuclear translocation of NF-& kappa;B were evaluated by the NF-& kappa;B nuclear translocation assay kit. Interleukin-6 (IL-6), interleukin-1 & beta; (IL-1 & beta;), and tumor necrosis factor-alpha (TNF-& alpha;) were assessed using ELISA. In vivo, ROS production was assessed by H2DCFDA, neutrophils and macrophages recruitment were evaluated in tail transection-induced and CuSO4-induced zebrafish inflammation models. Expression of inflammation related genes were also investigated based on CuSO4-induced zebrafish inflammation model.Key findings: MTHF-Ca treatment decreased LPS-induced ROS production, inhibited nuclear translocation of NF-& kappa;B and decreased the levels of IL-6, IL-1 & beta; and TNF-& alpha; in RAW264.7 cells. In addition, MTHF-Ca treatment inhibited ROS production, suppressed the recruitment of neutrophils and macrophages, and reduced the expression of inflammation related genes, including jnk, erk, nf-& kappa;b, myd88, p65, tnf-& alpha;, and il-1b in zebrafish larvae.Significance: MTHF-Ca may play an anti-inflammatory role by reducing the recruitment of neutrophils and macrophages and keeping the low levels of proinflammatory mediators and cytokines. MTHF-Ca may have a potential role in the treatment of inflammatory diseases.