The effect of steroidal and non-steroidal antiinflammatory drugs on chronic muscle inflammation

Zymosan (400 μg) and thioglycollate medium (0·1 ml of 2·4% w/v) have each been shown to induce a chronic inflammation when injected into the hamstring muscle of the mouse. The inflammation is characterized by an increase in muscle weight and N-acetylglucosaminidase concentrations. The response is not inhibited by oral treatment with hydrocortisone, dexamethasone or naproxen, but is inhibited by the local injection of methylprednisolone. The relevance of this model to polymyositis and fibrositis is discussed.