Willems M E, Stauber W T
Department of Physiology, West Virginia University, Morgantown 26506-9229, USA.
Arch Physiol Biochem. 2000 Dec;108(5):391-7. doi: 10.1076/apab.108.5.391.4289.
Following injection of tetanus toxin into rat gastrocnemius muscle to produce hypertonia, plantar flexor muscles were allowed to shorten (S, n=5) without restraint or held lengthened (L, n=3) by splinting. Saline injected rats served as control (n=5). One week after injection, peak forces during 3 stretches with passive muscles and acute isometric force deficits produced by 15 stretches of electrically stimulated muscles were examined under pentobarbital anesthesia. Isometric force and mass of plantar flexors were similar in S rats but 16% lower in L rats compared to control. Peak passive forces were highest in S rats but not different between L rats and control. At the end of the stretch protocol, isometric force deficits were 26% larger in S rats compared to L rats and 17% smaller in L rats compared to control. Acute isometric force deficits produced by stretches of active skeletal muscles were dependent on the muscle length maintained during hypertonia. Our animal model could be used to test rehabilitation interventions during hypertonia of skeletal muscles.
向大鼠腓肠肌注射破伤风毒素以产生张力亢进后，让跖屈肌缩短（S组，n = 5），不施加约束，或通过夹板固定使其保持延长状态（L组，n = 3）。注射生理盐水的大鼠作为对照（n = 5）。注射一周后，在戊巴比妥麻醉下，检查被动肌肉进行3次拉伸时的峰值力以及电刺激肌肉进行15次拉伸产生的急性等长力亏缺。S组大鼠跖屈肌的等长力和质量与对照组相似，但L组大鼠的等长力和质量比对照组低16%。S组大鼠的被动峰值力最高，但L组大鼠与对照组之间无差异。在拉伸方案结束时，S组大鼠的等长力亏缺比L组大鼠大26%，L组大鼠的等长力亏缺比对照组小17%。主动骨骼肌拉伸产生的急性等长力亏缺取决于张力亢进期间维持的肌肉长度。我们的动物模型可用于测试骨骼肌张力亢进期间的康复干预措施。
