Influence of nonsteroidal anti-inflammatory drug treatment duration and time of onset on recovery from exercise-induced muscle damage in rats.

Abstract

To determine if duration and time of onset of treatment with diclofenac sodium influence force recovery after exercise-induced muscle damage in rats. Randomized placebo-controlled trial. Animal laboratory. A total of 217 female adult Wistar rats. Rats were submitted to a protocol consisting of 450 eccentric contractions of the ankle dorsiflexors. Treatment by gavage with diclofenac sodium (1 mg/kg, twice daily) was started at different times pre- and postprotocol or for various treatment durations. In vitro contractile properties. When treatment was initiated shortly postprotocol, force recovery was roughly proportional to treatment duration during the first 3 days but not at 7 and 28 days postprotocol. A 7-day treatment was no more effective than 1- or 2-day treatments when force was measured at 7 and 28 days; however, such prolonged treatment had no deleterious effect on muscle force at either time. A single-dose prophylactic treatment was as effective as a 2-day treatment initiated soon after the protocol when force was assessed 2 days postprotocol; on the other end, a treatment delayed for 3 days had no effect when force was measured at 7 days. Treatment with diclofenac sodium extending past the acute inflammatory phase was no more effective than short and timely treatment in this model of skeletal muscle damage.