Melatonin reduces TNF-a induced expression of MAdCAM-1 via inhibition of NF-kB.

Background Endothelial MAdCAM-1 (mucosal addressin cell adhesion molecule-1) expression is associated with the oxidant-dependent induction and progress of inflammatory bowel disease (IBD). Melatonin, a relatively safe, potent antioxidant, has shown efficacy in several chronic injury models may limit MAdCAM-1 expression and therefore have a therapeutic use in IBD.

      Methods
      We examined how different doses of melatonin reduced endothelial MAdCAM-1 induced by TNF-a in an in vitro model of lymphatic endothelium. Endothelial monolayers were pretreated with melatonin prior to, and during an exposure, to TNF-a (1 ng/ml, 24 h), and MAdCAM-1 expression measured by immunoblotting.
    
    
      Results
      MAdCAM-1 was induced by TNF-a. Melatonin at concentrations over 100 μm (10-4 M) significantly attenuated MAdCAM-1 expression and was maximal at 1 mM.
    
    
      Conclusions
      Our data indicate that melatonin may exert therapeutic activity in IBD through its ability to inhibit NF-kB dependent induction of MAdCAM-1.