Luminal antioxidants enhance the effects of mesalamine in the treatment of chemically induced colitis in rats.
Previous experiments in rats with chemically induced colitis have shown that the antioxidant N-acetylcysteine plus mesalamine (5-ASA) exerted a significantly greater therapeutic effect in promoting mucosal healing when compared to either agent alone. The aims of the present study were to compare the effects of three antioxidants plus mesalamine vs. 5-ASA alone in treatment of colitis induced by trinitrobenzene sulfonic acid (TNBS) in rats.


METHODS
Three days following induction of TNBS colitis, rats received 8 days of rectal therapy with 5-ASA, or 5-ASA plus vitamin C (ascorbic acid), 5-ASA plus phenyl butylnitrone (PBN) and 5-ASA plus vitamin E (alpha-tocopherol). Distal colonic tissues were examined for microscopic colitis and myeloperoxidase (MPO) activity.


RESULTS
Global assessments of microscopic colitis induced by TNBS indicated that 5-ASA alone significantly changed colonic injury by -31%. Combination therapy with ascorbic acid plus 5-ASA or alpha-tocopherol plus 5-ASA caused further significant change in TNBS colitis by -65 and -82%, respectively. Each of these values was significantly below scores observed with 5-ASA as monotherapy. Reduction in colitis with PBN plus 5-ASA was not different from 5-ASA alone. MPO activity was decreased significantly in response to monotherapy with 5-ASA and each of the antioxidants plus 5-ASA when compared to TNBS. alpha-Tocopherol plus 5-ASA, however, was the only treatment strategy that reduced significantly MPO activity below that recorded for 5-ASA alone. In conclusion, our results indicate that antioxidants other than N-acetylcysteine significantly enhance the therapeutic effectiveness of 5-ASA in the treatment of TNBS colitis. alpha-Tocopherol plus 5-ASA exerted profound anti-inflammatory and reparative effects upon colitis induced by TNBS.
Ancha
Hanumantha R
HR
Department of Gastroenterology, University of Oklahoma Health Sciences Center, 920 Oklahoma City, OK 73104, USA.
Kurella
Ravi R
RR
McKimmey
Christine C
CC
Lightfoot
Stanley
S
Harty
Richard F
RF
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000494:pharmacology / Q000627:therapeutic use; D003092:Colitis / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology*; D003497:Cyclic N-Oxides / Q000494:pharmacology / Q000627:therapeutic use; D004195:Disease Models, Animal; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology; D008297:Male; D019804:Mesalamine / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014302:Trinitrobenzenesulfonic Acid; D014810:Vitamin E / Q000494:pharmacology / Q000627:therapeutic use
D000975:Antioxidants; D003497:Cyclic N-Oxides; D014810:Vitamin E; C029217:phenyl-N-tert-butylnitrone; D019804:Mesalamine; D014302:Trinitrobenzenesulfonic Acid; D001205:Ascorbic Acid