Dose Effect Relationship of Methylsulfonylmethane on Carrageenan Induced Rat Paw Edema

Background & objectives: The purpose of this study was to show the dose response relationship of anti-inflammatory effect of methylsulfonylmethane (MSM) on carrageenan induced rat paw edema as an acute model of inflammation. Methods: A total of 54 male, Sprague-Dawley rats, weighing 180-190 g, were used. One hundred, 200, 400, 800 and 1200 mg/kg of MSM were administered intraperitoneally to the rats 30 minutes before induction of paw edema with injection of 0.1% carrageenan. Diclofenac was used as a control drug. Rats were divided into three groups: MSM, diclofenac and normal saline, and their paw tissue were collected for the study of inflammatory and oxidative markers (MDA, GSH, TNF-α and IL-1 β). The relationship between the different concentrations of MSM and decrease in rat paw edema was calculated using a simple Emax model. Results: the ED50 value for effect of MSM on carrageenan induced rat paw edema was 193±9.7 mg/kg. A significant reduction in paw edema following administration of MSM at 200, 400, 800 and 1200 mg/kg was observed, but statistical analysis did not reveal any significant reduction in paw edema after administration of 100 mg/kg. MSM did not show statistically significant difference from control group in tissue level of GSH, but it was able to decrease MDA level significantly. MSM was able to significantly alleviate IL-1 β and TNF-alpha tissue levels. Conclusion: The recommended anti-inflammatory dosing range of MSM is 200-800 mg/kg for pharmacological studies in rats and the average appropriate dose is 400 mg/kg. Also, it seems that anti-inflammatory effect of MSM is more profound than its anti-oxidant effects