Effects of prolonged undernutrition on structure and function of the diaphragm.
Effects of prolonged undernutrition on structure and function of the diaphragm.
复制标题
长期营养不良对膈肌结构和功能的影响。
DOI：
10.1152/jappl.1985.58.4.1354
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Kapoor,S
中科院分区：
文献类型：
--
作者：
Kelsen,SG;Ference,M;Kapoor,S
本研究探讨了长期营养不良对横隔膜结构和力量生成能力的影响。对58只叙利亚仓鼠进行了研究，在4周的时间里，饲料减少了33%。60只动物随机喂食类似的食物作为对照。从质量(湿重和干重)、厚度、纤维组成和纤维大小评估横隔肌的结构。在一定的肌肉长度(长度-张力关系)范围内，研究了电刺激膈神经时，分离肌条在体外产生的等长力。在营养不良的动物中，体重下降了25%+/-5%。营养不良动物的横隔膜湿重和干重、肌肉厚度、快速糖酵解(FG)和快速氧化(FO)纤维横截面积显著小于对照动物，且与体重下降相关。两组慢氧化(SO)纤维的横截面积相同。营养不良动物FG纤维百分率略有下降，SO纤维百分率上升。与对照组相比，营养不良动物的最大等长张力降低，但长度-张力关系的位置和形状在两组中相同。肌力的减少似乎是由肌肉质量的减少来解释的，因为根据横截面面积或组织重量校正的张力在两组中是相同的。因此，肌肉机械效率似乎不受营养不良的影响。这些数据表明，长期营养不良会导致横隔肌结构的有害变化，从而削弱其产生力量的能力。
The present study examined the effect of prolonged undernutrition on diaphragmatic structure and force-generating ability. Studies were performed on 58 Syrian hamsters in which the feed was reduced by 33% for a 4-wk period. Sixty animals fed a similar diet ad libitum served as controls. Diaphragm muscle structure was assessed from its mass (wet and dry weight), thickness, fiber composition, and fiber size. Isometric force produced in vitro by isolated muscle strips in response to electrical stimulation of the phrenic nerve was examined over a range of muscle lengths (length-tension relationship). In undernourished animals, body weight decreased 25 +/- 5%. Diaphragm wet and dry weight, muscle thickness, and the cross-sectional area of fast-glycolytic (FG) and fast-oxidative (FO) fibers were significantly less in undernourished than control animals and correlated with reductions in body weight. The cross-sectional area of slow-oxidative (SO) fibers was the same in the two groups. The percentage of FG fibers in undernourished animals was decreased slightly and the percentage of SO fibers increased. Maximum isometric tension was reduced in undernourished animals as compared with controls, but the position and shape of the length-tension relationship was the same in the two groups. Reductions in muscle force appeared to be explained by decreases in muscle mass, since tension corrected for cross-sectional area or tissue weight was the same in the two groups. Therefore muscle mechanical efficiency appeared to be unaffected by undernutrition. These data indicate that prolonged undernutrition causes deleterious changes in diaphragm muscle structure that impair its ability to generate force.