Document Detail

Analysing the role of COX-2 in acute oesophagitis and in melatonin-exerted protection against experimental reflux oesophagitis in rats.
MedLine Citation:
PMID:  22060288     Owner:  NLM     Status:  In-Data-Review    
Objectives  Cyclooxygenase(COX)-2 is implicated in variety of pathophysiological processes, although its role in acute reflux oesophagitis is debatable. This study was designed to evaluate the role of COX-2 during oesophagitis and in melatonin-elicited protection in rats. Methods  Reflux oesophagitis was induced in rats by ligating the pyloric end and the limiting ridge of the stomach for 5 h. Celecoxib (COX-2 blocker; 10 mg/kg), 16,16-dimethyl prostaglandinE(2) (dmPGE(2) ; a synthetic analogue of PGE(2) ; 10 µg/kg), melatonin (20 and 40 mg/kg) and omeprazole (10 mg/kg) were given intra-peritoneally 45 min before induction of oesophagitis in rats. Alterations in COX-1 and 2 gene expression and protein levels level were analysed via RT-PCR and Western blotting, respectively. Mucosal PGE(2) level and myeloperoxidase (MPO) activity were measured using an enzyme immunoassay (EIA) kit and spectrophotometrically, respectively. Key findings  COX-2 over-expression during reflux oesophagitis promotes inflammation of the oesophagus as celecoxib pretreatment significantly reduced tissue damage and MPO activity in rats with reflux oesophagitis (RE-rats). By contrast, dmPGE(2) pretreatment significantly exacerbated tissue injury and simultaneously increased COX-2 expression, PGE(2) levels and MPO activity in RE-rats. Further, melatonin pretreatment significantly reduced the tissue injury, COX-2 over-expression, PGE(2) level and MPO activity in RE-rats. Melatonin offered more potent suppression of COX-2, PGE(2) and MPO activity than the proton-pump inhibitor omeprazole; however, both reduced the lesion injury to a similar extent. Melatonin at a dose of 20 mg/kg failed to inhibit significantly the dmPGE(2) -induced tissue damage, COX-2 expression, PGE(2) level and MPO activity in RE-rats while at a higher dose of 40 mg/kg it significantly attenuated these changes. Conclusion  Our results suggest that COX-2 plays an important pro-inflammatory role during acute reflux oesophagitis in rats and its inhibition contributes significantly to melatonin-exerted protection against reflux oesophagitis.
Pratibha Singh; Neetu Singh; Gautam Palit
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Publication Detail:
Type:  Journal Article     Date:  2011-10-10
Journal Detail:
Title:  The Journal of pharmacy and pharmacology     Volume:  63     ISSN:  2042-7158     ISO Abbreviation:  J. Pharm. Pharmacol.     Publication Date:  2011 Dec 
Date Detail:
Created Date:  2011-11-08     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0376363     Medline TA:  J Pharm Pharmacol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1572-80     Citation Subset:  IM    
Copyright Information:
© 2011 The Authors. JPP © 2011 Royal Pharmaceutical Society.
Division of Pharmacology, Central Drug Research Institute, C.S.I.R, Lucknow, Uttar Pradesh, India.
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