Effects of Prolonged Stretching for Prevention of Joint Contracture in Mice

本研究では, 臥床によって起こる拘縮を動物実験でシミュレーションし, その進行過程で持続的伸張運動を行い, 拘縮の予防に効果的な実施時間を検討した。8週齢のIcR系雄マウス34匹を対照群7匹と実験群27匹に振り分け, 実験群は後肢懸垂法に加え, 両側足関節を最大底屈位で固定し, 2週間飼育した。そして, 実験群の内6匹は固定のみとし, 21匹は週5回の頻度で足関節屈筋群に持続的伸張運動を実施した。なお, 実施時間は10分(n=8), 20分(n=7), 30分(n=6)とした。結果, 持続的伸張運動による拘縮の進行抑制効果は実施時間10分では認められないものの, 20分, 30分では認められ, 実施時間が長いほど効果的であった。しかし, 30分間の持続的伸張運動でも拘縮の発生を完全に予防することはできず, 今後は実施時間を延長することや他の手段の影響を検討する必要がある。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±1.5g) 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 10min (n=8) , 20min (n=7) or 30min (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 10min, and can be prevented in periods of stretch lasting 20min or more. But the progression of joint contracture can not complete1y prevented in periods of stretch lasting 30min