Favorable response to subcutaneous administration of infliximab in rats with experimental colitis.

AIM: To investigate the influence of infliximab (Remicade) on experimental colitis produced by 2,4,6,trinitrobenzene sulfonic acid (TNBS) in rats. METHODS: Thirty-six Wistar rats were allocated into four groups (three groups of six animals each and a fourth of 12 animals). Six more healthy animals served as normal controls (Group 5). Group 1: colitis was induced by intracolonic installation of 25 mg of TNBS dissolved in 0.25 mL of 50% ethanol and infliximab was subcutaneously administered at a dose of 5 mg/kg BW; Group 2: colitis was induced and infliximab was subcutaneously administered at a dose of 10 mg/kg BW; Group 3: colitis was induced and infliximab was subcutaneously administered at a dose of 15 mg/kg BW; Group 4: colitis was induced without treatment with infliximab. Infliximab was administered on d 2-6. On the 7(th) d, all animals were killed. The colon was fixed in 10% buffered formalin and examined by light microscopy for the presence and activity of colitis and the extent of tissue damage. Tumor necrosis factor-alpha (TNF-alpha) and malondialdehyde (MDA) were also measured. RESULTS: Significant differences concerning the presence of reparable lesions and the extent of bowel mucosa without active inflammation in all groups of animals treated with infliximab compared with controls were found. Significant reduction of the tissue levels of TNF-alpha in all groups of treated animals as compared with the untreated ones was found (0.47+/-0.44, 1.09+/-0.86, 0.43+/-0.31 vs 18.73+/-10.53 respectively). Significant reduction in the tissue levels of MDA was noticed in group 1 as compared to group 4, as well as between groups 2 and 4. CONCLUSION: Subcutaneous administration of infliximab reduces the inflammatory activity as well as tissue TNF-alpha and MDA levels in chemical colitis in rats. Infliximab at a dose of 5 mg/kg BW achieves better histological results and produces higher reduction of the levels of TNF-alpha than at a dose of 10 mg/kg BW. Infliximab at a dose of 5 mg/kg BW produces higher reduction of tissue MDA levels than at a dose of 15 mg/kg BW.

Beneficial effect of a novel non-steroidal anti-inflammatory agent with basic character and antioxidant properties on experimental colitis in rats.

Ulcerative colitis is a chronic disorder of unknown etiology. Conservative treatment remains empirical, even today. The aim of this study was to test the efficacy of a novel non-steroidal anti-inflammatory agent [5-(2-hydroxy-ethylamino)-1-cyclohexyl-2-pentanone] (compound A), with basic character and antioxidant properties on an experimental model of ulcerative colitis in rats. The effect of this compound was compared with that of methylprednisolone on the histological abnormalities and serum levels of tumor necrosis factor-alpha (TNF-alpha) in experimental colitis produced by 2,4,6-trinitrobenzenesulfonic acid (TNB). A total number of 24 rats were randomly assigned to one of four groups of six rats each. Group 1: colitis without treatment (disease control), group 2: normal animals (control), group 3: induction of experimental colitis treated with methylprednisolone (5.3 x 10(-3) mmol/kg i.v. every day for 7 days) and group 4: induction of experimental colitis plus administration of compound A (0.6 mmol/kg i.v. every day for 7 days). The administration of compound A resulted in a statistically significant reduction of the extent of tissue damage and of certain histological features (edema, inflammatory infiltration) (P<0.05). Compound A also resulted in a statistically significant reduction of the levels of serum TNF-alpha, compared to those of controls (P<0.005). The beneficial effect of this compound was probably due to the combination, on a single molecule, of anti-inflammatory and antioxidant properties as well as to its basic character. The reduction of the serum TNF-alpha levels could be one of the possible mechanism(s) of action of the compound. Further studies are necessary to establish the direct mechanism of action(s) of the drug and to evaluate its long-term efficacy and safety.