The effect of melatonin on plasma markers of inflammation and on expression of nuclear factor-kappa beta in acetic acid-induced colitis in the rat

Dig Dis Sci. 2013 Nov;58(11):3156-64. doi: 10.1007/s10620-013-2811-x. Epub 2013 Aug 8.

Abstract

Background and aims: Melatonin may be involved in gastrointestinal tract physiology and could affect inflammation-related gastrointestinal disorders. Rat models of ulcerative colitis imply melatonin is beneficial. To determine potential pathophysiological mechanisms, we assessed colonic nuclear factor-kappa beta expression and measured serum levels of pentraxin-3, lipid peroxides, and total thiols in an acetic acid model of this disease.

Materials and methods: Thirty rats were divided into five groups: a control group, an acetic acid-induced colitis group, a group treated with melatonin before colitis induction, a group treated short-term after colitis induction, and a group treated long-term after colitis induction. After four weeks, blood samples were taken for measurement of pentraxin-3, lipid peroxide, and total thiols. Sections of the colon were taken for histopathological examination and immunohistochemical detection of nuclear factor-kappa beta expression.

Results: Melatonin administration reduced nuclear factor-kappa beta immunohistochemical expression, reduced serum levels of lipid peroxide and pentraxin-3, and maintained serum levels of total thiols. However, in long-term treatment the protective effect of melatonin was not as marked.

Conclusion: Melatonin is effective in prevention and short-term treatment of the inflammatory process in acetic-acid induced colitis whereas the benefit of long-term treatment is unclear. Benefit may be linked to protection mechanisms against inflammatory processes by inhibiting the nuclear factor-kappa beta and conserving endogenous antioxidant reserves of total thiols, thus reducing the level of colonic damage possibly caused by lipid peroxides.

MeSH terms

  • Acetic Acid / toxicity*
  • Animals
  • Biomarkers / blood
  • Colitis / chemically induced*
  • Colitis / metabolism*
  • Gene Expression Regulation / drug effects*
  • Inflammation / blood
  • Inflammation / metabolism
  • Male
  • Melatonin / therapeutic use*
  • NF-kappa B / genetics
  • NF-kappa B / metabolism*
  • Rats

Substances

  • Biomarkers
  • NF-kappa B
  • Melatonin
  • Acetic Acid