Cannon J G, Fiatarone M A, Fielding R A, Evans W J
US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts.
J Appl Physiol (1985). 1994 Jun;76(6):2616-20. doi: 10.1152/jappl.1994.76.6.2616.
We measured the extent of complement activation and neutrophil mobilization after eccentric exercise to determine whether these responses were age dependent and whether they were associated with changes in plasma creatine kinase (CK), a marker for muscle membrane integrity. Repeated forced lengthening of a muscle as it develops tension causes immediate ultrastructural damage to sarcomeres, followed by delayed-onset muscle soreness and release of myocellular enzymes. This can be accomplished in quadriceps muscles by running downhill or by resisting bicycle pedals driven backward by a motor. Twelve older (61-72 yr) and 9 younger (20-32 yr) subjects performed one of these activities for 45 min at an intensity of 78 +/- 2% of maximum heart rate. For all subjects, a median increase of 21% in plasma des-Arg-C3a levels occurred immediately after the protocol, circulating neutrophils increased 66 +/- 10% by 4-6 h, and plasma CK increased 135 +/- 25% by 24 h. The peak increases in neutrophils correlated with the peak increases in des-Arg-C3a (rho = 0.662, P = 0.006), and the peak increases in CK correlated with the rise in neutrophils (rho = 0.523, P = 0.027). The increases in neutrophils and plasma CK were significantly smaller in the older subjects (P < 0.05). The results indicate that increased concentrations of circulating CK after muscle injury are associated with a sequential cascade of inflammatory mediators. Furthermore, neutrophil mobilization, but not complement activation, was diminished in older subjects in response to this stress.
我们测量了离心运动后补体激活和中性粒细胞动员的程度，以确定这些反应是否与年龄相关，以及它们是否与血浆肌酸激酶（CK）的变化有关，CK是肌肉膜完整性的标志物。当肌肉产生张力时反复被迫拉长会导致肌小节立即发生超微结构损伤，随后出现延迟性肌肉酸痛和肌细胞酶的释放。这可以通过下坡跑或抵抗由电机驱动向后转动的自行车踏板在股四头肌中实现。12名年龄较大（61 - 72岁）和9名年龄较小（20 - 32岁）的受试者以最大心率的78±2%的强度进行其中一项活动45分钟。对于所有受试者，实验方案结束后血浆去精氨酸 - C3a水平立即中位数增加21%，循环中性粒细胞在4 - 6小时增加66±10%，血浆CK在24小时增加135±25%。中性粒细胞的峰值增加与去精氨酸 - C3a的峰值增加相关（rho = 0.662，P = 0.006），CK的峰值增加与中性粒细胞的增加相关（rho = 0.523，P = 0.027）。年龄较大的受试者中性粒细胞和血浆CK的增加明显较小（P < 0.05）。结果表明，肌肉损伤后循环CK浓度的增加与炎症介质的顺序级联有关。此外，在这种应激反应中，年龄较大的受试者中性粒细胞动员减少，但补体激活未减少。
