Abstract
The purpose of this study was to determine whether prolonged stretching prevents joint contracture that has been followed by simulated bed rest in mice. Thirty-four male IcR mice (age, 8 weeks; weight, 34.6 ± 1.5 g) were divided randomly into control (n=7) and experimental (n=27) groups. In the experimental group, bilateral ankles of each mouse were fixed in full planter flexion with a non-elastic tape, and each mouse was raised with the hindlimbs unweighted for 2 weeks. Of six mice in the experimental group, bilateral ankles were immobilized throughout the 2 week experiment. Of the other mice of the experimental group, the tape of bilateral ankles was removed and the ankle flexor muscles were maximally stretched by dorsiflexing the ankle joint under anesthesia, for periods of 10 min (n=8), 20 min (n=7) or 30 min (n=6) per day, 5 days per week for 2 weeks. After experiments, each mouse was given an anesthetic and the range of movement of the ankle was measured with a goniometer. It was found that progression of joint contracture can not be prevented in periods of stretch lasting 10 min, and can be prevented in periods of stretch lasting 20 min or more. But the progression of joint contracture can not completely prevented in periods of stretch lasting 30 min.
