The acute effects of cigarette smoke exposure on muscle fiber type dynamics in rats
The acute effects of cigarette smoke exposure on muscle fiber type dynamics in rats
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DOI：
10.1371/journal.pone.0233523
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发表时间：
2020-05-20
期刊：
影响因子：
3.7
通讯作者：
Ngai, Shirley P. C.
中科院分区：
文献类型：
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作者：
Cheung, Kwok-Kuen;Fung, Timothy Kai-Hang;Ngai, Shirley P. C.
运动能力下降在慢性阻塞性肺疾病（COPD）患者和慢性吸烟者中很常见，并被认为与骨骼肌功能障碍有关。先前使用人体肌肉活检的研究表明，慢性吸烟者尤其是COPD患者的纤维类型发生了变化。然而，这些结果与衰老效应相混淆，因为慢性阻塞性肺病患者往往年龄较大。在本研究中，我们使用Sprague-Dawley大鼠建立了急性7天香烟烟雾暴露模型，以评估吸烟对比目鱼肌的早期影响。大鼠（每组n = 5）被随机分配到三种不同浓度的总颗粒物（TPM） （CSTPM2.5, CSTPM5, CSTPM10）的假空气（SA）或吸烟（CS）组。CS组比目鱼肌中I型纤维比例明显低于SA组，IIa型纤维比例明显高于SA组。其中，只有CSTMP10组柠檬酸合成酶活性显著低于SA组，肌肉肿瘤坏死因子- α水平显著高于SA组。肿瘤坏死因子α水平与I型和IIa型纤维百分比相关。然而，在纤维横截面积、体力活动或肺功能评估方面，组间没有发现显著差异。综上所述，急性吸烟可能直接引发骨骼肌糖酵解纤维类型转变的发生，而不受年龄的影响。
Reduced exercise capacity is common in people with chronic obstructive pulmonary diseases (COPD) and chronic smokers and is suggested to be related to skeletal muscle dysfunction. Previous studies using human muscle biopsies have shown fiber-type shifting in chronic smokers particularly those with COPD. These results, however, are confounded with aging effects because people with COPD tend to be older. In the present study, we implemented an acute 7-day cigarette smoke-exposed model using Sprague-Dawley rats to evaluate early effects of cigarette smoking on soleus muscles. Rats (n = 5 per group) were randomly assigned to either a sham air (SA) or cigarette smoking (CS) groups of three different concentrations of total particulate matters (TPM) (CSTPM2.5, CSTPM5, CSTPM10). Significantly lower percentages of type I and higher type IIa fiber were detected in the soleus muscle in CS groups when compared with SA group. Of these, only CSTMP10 group exhibited significantly lower citrate synthase activity and higher muscle tumor necrosis factor-alpha level than that of SA group. Tumor necrosis factor-alpha level was correlated with the percentage of type I and IIa fibers. However, no significant between-group differences were found in fiber cross-sectional area, physical activities, or lung function assessments. In conclusion, acute smoking may directly trigger the onset of glycolytic fiber type shift in skeletal muscle independent of aging.