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.
OBJECTIVE
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.


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.


CONCLUSIONS
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.
Department of Medical Physiology, Faculty of Medicine, Assiut University, Asyût, Egypt.
Hayam G
HG
Sayyed
Rumi J
RJ
Jaumdally
Naglaa K
NK
Idriss
Dalia A
DA
El Sers
Andrew
A
Blann
D019342:Acetic Acid / Q000633:toxicity*; D000818:Animals; D015415:Biomarkers / Q000097:blood; D003092:Colitis / Q000139:chemically induced* / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D007249:Inflammation / Q000097:blood / Q000378:metabolism; D008297:Male; D008550:Melatonin / Q000627:therapeutic use*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D051381:Rats
D015415:Biomarkers; D016328:NF-kappa B; D008550:Melatonin; D019342:Acetic Acid