Cholesterol conservation in skeletal muscle associated with age- and denervation-related atrophy.
Cholesterol conservation in skeletal muscle associated with age- and denervation-related atrophy.
复制标题
骨骼肌中的胆固醇保存与年龄和去神经相关的萎缩有关。
DOI：
10.1016/0006-8993(89)90995-5
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发表时间：
1989
期刊：
影响因子：
2.9
通讯作者：
Smith,DO
中科院分区：
文献类型：
--
作者：
Williams,KD;Smith,DO
测定了10月龄和25月龄大鼠全肌和离体肌膜中老龄萎缩和去神经萎缩肌肉的脂质组成。随着年龄的增长，肌肉质量下降了至少17%，但肌肉胆固醇浓度上升了15-20%。然而，磷脂浓度保持不变；因此，随着年龄的增长，胆固醇与磷脂的比例增加。血浆胆固醇水平也上升了35%，但这只能解释肌肉胆固醇与年龄相关差异的10%左右。同样，去神经支配后（7天）肌肉质量下降至少30%，但肌肉胆固醇与磷脂比值增加；去神经支配诱导反应的强度不受年龄的影响。为了定位衰老过程中胆固醇沉积的来源，在分离的肌膜、肌浆网和线粒体膜上重复这些实验。在这些主要的膜系统中，胆固醇和磷脂水平都没有随年龄发生显著变化。此外，依赖于胆固醇含量的肌层流动性不随年龄显著变化。在这个分辨率水平上，骨骼肌膜磷脂组成和流动性似乎不随年龄明显变化。在全肌肉中检测到的胆固醇-磷脂比率升高可能是由于胆固醇沉积在非肌纤维部位。
The lipid composition of muscles with age- and denervation-atrophy was assayed in whole muscle and isolated sarcolemma of rats aged 10 and 25 months. Although muscle mass decreased at least 17% during aging, muscle cholesterol concentration rose 15–20%. However, phospholipid concentrations were maintained; therefore, the cholesterol-to-phospholipid ratio increased during aging. Plasma cholesterol levels also rose 35%, but this could account for only about 10% of the age-related difference in muscle cholesterol. Likewise, following denervation (7 days) muscle mass decreased by at least 30%, but muscle cholesterol-to-phospholipid ratio increased; the magnitude of the denervation-induced response was unaffected by aging. To localize the source of cholesterol deposition during aging, these assays were repeated on isolated sarcolemma, sarcoplasmic reticulum, and mitochondria membrane fractions. Neither cholesterol nor phospholipid levels changed significantly with age in any of these major membrane systems. Furthermore, sarcolemmal fluidity, which depends on cholesterol content, did not vary significantly with age. At this level of resolution, it thus appears that skeletal muscle membrane phospholipid composition and fluidity do not change appreciably with age. Elevated cholesterol-to-phospholipid ratios detected in whole muscle may be due to cholesterol deposition in non-myofiber locations.