Qualitative alteration of peripheral motor system begins prior to appearance of typical sarcopenia syndrome in middle-aged rats.
Qualitative alteration of peripheral motor system begins prior to appearance of typical sarcopenia syndrome in middle-aged rats.
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DOI：
10.3389/fnagi.2014.00296
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发表时间：
2014
影响因子：
4.8
通讯作者：
Uchiyama Y
中科院分区：
文献类型：
--
作者：
Tamaki T;Hirata M;Uchiyama Y
使用年轻、成年、中年和老年大鼠检查外周运动系统的质的变化，以评估肌肉减少症症状出现之前和之后的情况。肌肉质量和力量的显著损失以及具有神经支配的神经纤维损失的慢型纤维分组被用作肌肉减少症的典型标志。动态抽搐和强直张力和诱发肌电图（EEMG）通过电刺激坐骨神经麻醉下使用我们的力-距离传感器系统测量坐骨神经切除术前后。进行数字和模拟数据采集，并计算与张力的串行抽动的缩短和放松速度。被动拉伸中的肌肉压痛也被测量为拉伸吸收能力，与肌肉结缔组织的组织学定量相关。结果表明，本模型的有效性，其中老年大鼠明显表现出典型的肌肉减少症的迹象，特别是在快速型跖肌，而缓慢型比目鱼肌表现出相对较轻的症状。这些观察结果表明，以下质的变化作为肌肉减少症的病理生理机制：（1）缩短和放松速度的抽搐减少;（2）随着结缔组织成分的增加，肌肉压痛下降;（3）运动单位（MU）的募集受损。（强直力和EEMG的突然降低）;和（4）神经肌肉接头中的易疲劳性。这些发现可能与快速型MU、肌肉力量和收缩速度的显著损失密切相关，这可能是老年人福尔斯跌倒的致病因素。重要的是，这些症状中的一些开始于中年大鼠，没有显示出其他肌肉减少症的迹象。因此，预防应从中年开始，这样可以保持相对较高的运动能力。
Qualitative changes in the peripheral motor system were examined using young, adult, middle-aged, and old-aged rats in order to assess before and after the appearance of sarcopenia symptoms. Significant loss of muscle mass and strength, and slow-type fiber grouping with a loss of innervated nerve fibers were used as typical markers of sarcopenia. Dynamic twitch and tetanus tension and evoked electromyogram (EEMG) were measured via electrical stimulation through the sciatic nerve under anesthesia using our force-distance transducer system before and after sciatectomy. Digital and analog data sampling was performed and shortening and relaxing velocity of serial twitches was calculated with tension force. Muscle tenderness in passive stretching was also measured as stretch absorption ability, associated with histological quantitation of muscle connective tissues. The results indicated the validity of the present model, in which old-aged rats clearly showed the typical signs of sarcopenia, specifically in the fast-type plantaris muscles, while the slow-type soleus showed relatively mild syndromes. These observations suggest the following qualitative alterations as the pathophysiological mechanism of sarcopenia: (1) reduction of shortening and relaxing velocity of twitch; (2) decline of muscle tenderness following an increase in the connective tissue component; (3) impaired recruitment of motor units (MUs) (sudden depression of tetanic force and EEMG) in higher stimulation frequencies over 50–60 Hz; and (4) easy fatigability in the neuromuscular junctions. These findings are likely to be closely related to significant losses in fast-type MUs, muscle strength and contraction velocity, which could be a causative factor in falls in the elderly. Importantly, some of these symptoms began in middle-aged rats that showed no other signs of sarcopenia. Thus, prevention should be started in middle age that could be retained relatively higher movement ability.
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DOI：
10.1093/gerona/63.8.829
发表时间：
2008-08-01
影响因子：
5.1
作者：
Clark, Brian C.;Manini, Todd M.
通讯作者：
Manini, Todd M.
DOI：
10.1093/gerona/glt135
发表时间：
2014-06-01
影响因子：
5.1
作者：
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通讯作者：
Faulkner, John A.
DOI：
10.1067/mlc.2001.113504
发表时间：
2001-04-01
期刊：
JOURNAL OF LABORATORY AND CLINICAL MEDICINE
影响因子：
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作者：
Morley, JE;Baumgartner, RN;Nair, KS
通讯作者：
Nair, KS
影响因子：
4
作者：
Lang, T.;Streeper, T.;Cawthon, P.;Baldwin, K.;Taaffe, D. R.;Harris, T. B.
通讯作者：
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影响因子：
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作者：
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