Carvalho A J, Evans P J, McKee N H, Mackinnon S E
Department of Surgery, University of Toronto, Ontario, Canada.
J Reconstr Microsurg. 1997 Jul;13(5):351-9. doi: 10.1055/s-2007-1006415.
The nature of reinnervation of fast- and slow-twitch skeletal muscles, as assessed by contractile characteristics, was determined in a rat sciatic-nerve graft model. The isometric contractile function of the fast-twitch plantaris and slow-twitch soleus muscles from hindlimbs of adult male Lewis rats (225 to 250 g) was assessed at 16 weeks after sciatic-nerve grafting. A 3-cm interposition sciatic-nerve graft was performed in the following groups: fresh syngeneic (n = 10), fresh allogeneic (n = 11), 3-week stored allogeneic (n = 9), and freeze-thawed allogeneic (n = 9). A control group consisted of 8 normal unoperated rats. Contractile properties were assessed by stimulating the muscles indirectly via the sciatic nerve. At 16 weeks, soleus and plantaris muscle masses were 40 and 52 percent of controls, while their respective absolute tetanic forces (N) were less than 65 and 45 percent of controls. Analysis of time-dependent contractile parameters showed that the soleus/plantaris ratios for time to peak tension (TTP) and maximum rate of force development (df/dt) were not significantly altered following grafting. However, the ratio for half relaxation time (1/2RT) was significantly reduced from 4.44 +/- 0.62 toward a value of 1 following grafting. In this study, the authors found that, when fast and slow muscles were reinnervated from a common nerve, maintenance of differences in rate of force development supported selective reinnervation, while loss of differences in time of force relaxation supported random reinnervation.
通过收缩特性评估，在大鼠坐骨神经移植模型中确定了快肌和慢肌骨骼肌再支配的性质。在成年雄性Lewis大鼠（225至250克）后肢的快肌比目鱼肌和慢肌比目鱼肌的等长收缩功能在坐骨神经移植后16周进行评估。在以下组中进行了3厘米的坐骨神经间置移植：新鲜同基因（n = 10）、新鲜异基因（n = 11）、储存3周的异基因（n = 9）和冻融异基因（n = 9）。对照组由8只未手术的正常大鼠组成。通过经坐骨神经间接刺激肌肉来评估收缩特性。在16周时，比目鱼肌和比目鱼肌的肌肉质量分别为对照组的40%和52%，而它们各自的绝对强直力（N）小于对照组的65%和45%。对时间依赖性收缩参数的分析表明，移植后比目鱼肌/比目鱼肌在达到峰值张力时间（TTP）和最大力量发展速率（df/dt）方面的比值没有显著改变。然而，半松弛时间（1/2RT）的比值在移植后从4.44±0.62显著降低至1。在这项研究中，作者发现，当快肌和慢肌由同一神经再支配时，力量发展速率差异的维持支持选择性再支配，而力量松弛时间差异的丧失支持随机再支配。
