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Melatonin Inhibits a Process that Leads to Colitis in Animal Study

Published June 8th, 2008 in What's in the News

Melatonin Inhibits a Process that Leads to Colitis in Animal Study

VRP Staff
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In an animal study published in the Journal of Pineal Research, melatonin inhibited enzymes known as matrix metalloproteinases, thought to be involved in the development of colitis due to their ability to break down proteins such as collagen.

Matrix metalloproteinases function in tumor cell invasion and metastasis, wound healing, and angiogenesis (the formation of new blood vessels). They are normally found in the spaces between cells (extracellular) in tissues and play a role in breaking down extracellular matrix proteins such as collagens. This poses a problem in regards to cancer, since extracellular matrix compartments act as the primary barriers to tumor growth and spread. Matrix metalloproteinases have been linked to breast, ovarian, colorectal, and lung cancers and matrix metalloproteinase inhibitors are becoming a common treatment to inhibit tumor metastasis and angiogenesis.

Matrix metalloproteinases also play an important role in the pathogenesis of colitis. Additionally, past studies have documented that melatonin exerts an important anti-inflammatory effect in colitis. Therefore, researchers investigated melatonin’s effects on experimental colitis in rats to see whether it exerted its effects by influencing matrix metalloproteinases.

Researchers induced colitis in animals. Four days later, the scientists noted colonic damage in the rodents along with increased levels of the inflammatory marker TNF-alpha. The researchers then measured matrix metalloproteinase activity in colon tissues from the rats with colitis.

When the rodents were given melatonin, the hormone prevented colon injury and lipid peroxidation in rats 4 days after colitis was induced. Melatonin also reduced matrix metalloproteinase activities that occurred in the colon tissues of the rats with induced colitis. The reduced activity of the matrix metalloproteinases was associated with an accompanying reduction in the inflammatory marker TNF-alpha.

The researchers concluded that melatonin’s ability to reduce experimental colitis in rats is related to a reduction in matrix metalloproteinase activities and expression.


Esposito E, Mazzon E, Riccardi L, Caminiti R, Meli R, Cuzzocrea S. Matrix metalloproteinase-9 and metalloproteinase-2 activity and expression is reduced by melatonin during experimental colitis. J Pineal Res. 2008 Apr 21. Published online ahead of print.