Abstract
Melatonin is a natural hormone-like compound mainly produced by the pineal gland. It possesses
a number of important biologic activities, including oncostatic, anti-oxidant and immunostimulatory actions; however, the dose-response relationship was not well characterized. The present study was designed to evaluate the dose-response relationship for the anti-inflammatory activity of melatonin in an experimental animal model of formalin-induced chronic inflammation in rats. Fifty-four Sprague-Dawley rats were allocated into 9 subgroups, with six rats in each one. These subgroups represent saline-treated, piroxicam (5 mg/kg), dexamethasone (1mg/kg) and melatonin (0.25, 0.5, 1.0, 2.0, 5 and 10 mg/kg)-treated subgroups. All drugs were administered intraperitoneally (IP) 30 minutes before inducing inflammation by injecting 0.1 ml of 2% formalin into the subplanter surface of the right hind paw of ether-anesthetized rats and continuing for 7 consecutive days. The results of the study showed that all treatment groups (except melatonin 0.25 mg/kg) significantly reduced paw thickness (P<0.05) compared to the saline treated group after 7 days of treatment. The melatonin 5 mg/kg group produced the highest level of anti-inflammatory activity, which is comparable to that of the piroxicam 5 mg/kg group. In conclusion, melatonin exerts a well defined anti-inflammatory activity in an animal model of chronic inflammation that is comparable in certain circumstances to that produced by standard drugs in this respect.
Customer Reviews
Thanks for submitting your comment!