Russ David W, Grandy Jessica S
J Cachexia Sarcopenia Muscle. 2011 Sep;2(3):175-180. doi: 10.1007/s13539-011-0033-7. Epub 2011 Jul 7.
Aging skeletal muscle frequently exhibits a reduction in force produced per unit muscle tissue, variously termed muscle quality, specific tension or dynapenia. Muscles from animals in which desmin expression is reduced exhibit similar properties, raising the possibility that reduced desmin expression contributes to impaired force production in aging muscles. METHODS: We examined expression of desmin and synemin, both intermediate filament proteins, in the plantarflexor muscles of adult (6-8 months) and older (24 months) rats. We have previously reported age-related reductions in muscle quality and sarcoplasmic reticulum function in these animals. RESULTS: Significant effects of age and muscle were found for the expression of desmin (P = 0.040 and <0.001 respectively), but not synemin. Desmin expression was increased in the aging muscles, with the greatest changes observed in the gastrocnemius muscles. Muscle quality, but not muscle mass, was reduced in the aging plantarflexor muscles. CONCLUSIONS: Loss of desmin does not account for reduced force production in aging muscles. The potential effects of the age-related increase in desmin on muscle function remain unclear, but may include dissipation of contractile force.
衰老的骨骼肌常常表现出每单位肌肉组织产生的力量下降，这种情况有多种称谓，如肌肉质量、比张力或肌力减退。来自结蛋白表达降低的动物的肌肉也表现出类似特性，这增加了结蛋白表达降低导致衰老肌肉力量产生受损的可能性。方法：我们检测了成年（6 - 8个月）和老年（24个月）大鼠跖屈肌中结蛋白和伴肌动蛋白这两种中间丝蛋白的表达。我们之前报道过这些动物中与年龄相关的肌肉质量和肌浆网功能下降。结果：发现年龄和肌肉对结蛋白的表达有显著影响（分别为P = 0.040和<0.001），但对伴肌动蛋白没有影响。衰老肌肉中的结蛋白表达增加，腓肠肌中观察到的变化最大。衰老的跖屈肌中肌肉质量下降，但肌肉量未下降。结论：结蛋白的缺失并不能解释衰老肌肉中力量产生的降低。与年龄相关的结蛋白增加对肌肉功能的潜在影响尚不清楚，但可能包括收缩力的消散。
