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Acutely administered melatonin is beneficial while chronic melatonin treatment aggravates the evolution of TNBS-induced colitis
- Source :
- Journal of Pineal Research. 40:48-55
- Publication Year :
- 2006
- Publisher :
- Wiley, 2006.
-
Abstract
- The aim of this study was to evaluate the effects of melatonin on the inflammatory response and hydroxyproline production in an experimental acute and chronic model of trinitrobenzene sulfonic (TNBS) acid-induced colitis in Wistar rats. In the acute model, melatonin (0.5, 1, and 2 mg/kg, i.p.) was applied 48, 24, and 1 hr prior to the induction of colitis and 24 and 48 hr after; the severity of colitis was less evident in melatonin-treated animals with significant response in the group treated with 2 mg/kg. All doses investigated significantly reduced the myeloperoxidase activity (MPO). In the chronic studies, melatonin (1 and 2 mg/kg, i.p.) was administered daily 24 hr before hapten instillation and for 7 or 21 days after TNBS; melatonin (2 mg/kg) worsened colitis evolution in the 21-day study with a significant increase in MPO activity and tumor necrosis factor-alpha production with respect to TNBS group. Histological slides were in concordance with macroscopic data where areas of extensive necrosis and edema, fibrosis, and absence of regenerated epithelium were observed. Moreover, the hydroxyproline determination, used as indicator of collagen production and fibrosis, also showed a marker increase. The results obtained in this experimental model showed that short-term administration is protective while in the long term it negatively influences evolution of inflammatory colitis; therefore, the immunostimulatory effect of melatonin in some situations when given chronically, such as during inflammatory bowel disease, might lead to negative consequences.
- Subjects :
- Male
medicine.medical_specialty
Colon
Inflammatory bowel disease
Drug Administration Schedule
Melatonin
Hydroxyproline
chemistry.chemical_compound
Endocrinology
Fibrosis
Internal medicine
Edema
medicine
Animals
Intestinal Mucosa
Rats, Wistar
Colitis
Peroxidase
biology
Tumor Necrosis Factor-alpha
business.industry
medicine.disease
Rats
Disease Models, Animal
Trinitrobenzenesulfonic Acid
chemistry
Myeloperoxidase
biology.protein
Tumor necrosis factor alpha
medicine.symptom
business
medicine.drug
Subjects
Details
- ISSN :
- 1600079X and 07423098
- Volume :
- 40
- Database :
- OpenAIRE
- Journal :
- Journal of Pineal Research
- Accession number :
- edsair.doi.dedup.....54f53059e335b51ff26d363e69a4b483
- Full Text :
- https://doi.org/10.1111/j.1600-079x.2005.00275.x