静态负荷对家兔骨骼肌胞浆Ca^(2+)含量及肌浆网功能的影响

Effects of static load on Ca^(2+)concentration of cytoplasm and the function of sarcoplasmic reticulum in rabbit skeletal muscle

目的 探讨静态负荷致肌肉损伤的机制。方法 以原子吸收光谱法测定家兔腰肌胞浆及肌浆网的Ca2 +含量 ;根据酶促水解ATP生成磷的含量表示Ca2 + Mg2 + ATP酶活力 ;用速率法测定血清中肌酸磷酸激酶 (CK)的活力。结果 施加静态负荷 1周、4周时家兔腰肌胞浆的Ca2 +含量 [(2 1.5 7± 2 .75 )、(14.2 5± 4.5 0 )nmol/mgpro]显著高于对照组 [(8.2 5± 0 .11)、(7.75± 0 .75 )nmol/mgpro],经统计学处理 ,差异有显著性 (P <0 .0 1、P <0 .0 5 ) ,8周时与对照组相比 ,差异无显著性(P >0 .0 5 ) ;实验 1周、4周时肌浆网Ca2 +含量下降 [(181.0 0± 40 .0 0 )、(187.5 0± 5 5 .0 0 )nmol/mgpro],与对照组 [(2 6 9.75± 47.0 0 )、(2 86 .2 5± 6 4.2 5 )nmol/mgpro]相比 ,差异有显著性 (P <0 .0 5 ) ;在施加静态负荷 1周时 ,肌浆网Ca2 + Mg2 + ATP酶活力明显降低 [(8.82± 1.13)nmolPi·min-1·mgpro-1],差异有显著性 (P <0 .0 1) ,第 4周和 8周时接近正常水平。施加静态负荷 1周、4周、8周时 ,实验组家兔血清CK活力分别为 (2 0 48± 12 6 3)、(5 6 6± 2 6 6 )、(76 6± 32 3)U/L ,与对照组 [(2 6 9± 118)、(2 33± 6 6 )、(30 3± 16 6 )U/L]比较明显升高 ,差异有显著性 (P <0 .0 1、P <0 .0 5 )。胞浆Ca2

Objective To study the mechanism of muscle injury induced by static load. Methods Ca 2+ concentratioins of cytoplasm and sarcoplasmic reticulum(SR) in rabbit psoas muscle were measured by spectrophotometry.The contents of phosphorus from ATP were measured by using enzyme hydrolysis as indicator of activity of Ca 2+ Mg 2+ ATPase.Creatine kinase(CK) activity was measured by rating method. Results The Ca 2+ concentrations of cytoplasm were (21.57±2.75)nmol/mg pro and (14.25±4.50)nmol/mg pro respectively after 1 week and 4 weeks of static load,significantly higher than those of controls(8.25±0.11)nmol/mg pro and (7.75± 0.75) nmol/mg pro( P <0.01).There was no significant difference of Ca 2+ concentration of cytoplasm in 8 weeks between experimental and control groups.After 1 week and 4 weeks,Ca 2+ concentrations of SR were (181.00± 40.00) nmol/mg pro and (187.50±55.00)nmol/mg pro respectively,significantly lower than those of control (269.75 ±47.00)nmol/mg pro,(286.25±64.25)nmol/mg pro( P <0.05).The Ca 2+ Mg 2+ ATPase activity in 1 week group was (8.82±1.13)nmol Pi·min -1 ·mg pro -1 and it was lower than that of control group.CK activities in serum were (2?048±1?263)U/L,(566±266)U/L,(766±323)U/L respectively after 1 week,4 weeks,8 weeks,significantly higher than those in control groups(269±118)U/L,(233±66)U/L,(303±166)U/L( P <0.01, P <0.05). The activity of CK in serum was significantly correlated with Ca 2+ concentration in cytoplasm( r = 0.91, P <0.05). Conclusion The disorder of intracellular Ca 2+ homeostasis may play an important role in the etiology of muscle injury induced by static load.