Effect of long-term undernutrition on male and female rat diaphragm contractility, fatigue, and fiber types.
Effect of long-term undernutrition on male and female rat diaphragm contractility, fatigue, and fiber types.
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长期营养不良对雄性和雌性大鼠膈肌收缩力、疲劳和纤维类型的影响。
DOI：
10.1152/jappl.1994.76.4.1540
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Cahill,J
中科院分区：
文献类型：
--
作者：
Prezant,DJ;Richner,B;Aldrich,TK;Valentine,DE;Gentry,EI;Cahill,J
研究了长期营养不良（10周）对雄性和雌性大鼠膈肌收缩力、疲劳和纤维类型比例的影响。在37摄氏度的直接刺激下，在体外隔膜肋条制备中测量了收缩性和抗疲劳指数。营养不良允许男性和女性继续生长，但体重增加大幅减少。营养不良雄鼠的最终体重（74 +/- 3%）显著低于母鼠（90 +/- 5%），但增重在营养不良雄鼠（58 +/- 5%）和母鼠（60 +/- 3%）之间无显著差异。只有男性营养不良显著降低了肋膈肌重量（为对照组的77±5%）。横截面积归一化后的横膈膜力与男性或女性控制值没有显著差异。在所有刺激频率下，营养不良男性的疲劳抵抗指数（疲劳/基线力）都有所增加，而营养不良女性则没有。涉及I型和II型纤维的肋膈萎缩发生在营养不良的男性中，而不发生在营养不良的女性中。综上所述，尽管长期营养不良使男性和女性的体重增加达到相似的水平（相对于对照组），但女性的横膈膜重量、功能和结构得到了很好的保存，尽管发生了横膈膜萎缩，但男性的收缩性和抗疲劳能力得到了保留。
The effects of long-term undernutrition (10 wk) on diaphragm contractility, fatigue, and fiber type proportions were studied in male and female rats. Contractility and fatigue resistance indexes were measured in an in vitro diaphragm costal strip preparation by using direct stimulation at 37 degrees C. Undernutrition allowed for continued growth in males and females but with substantial reductions in weight gain. Relative to control rats of the same sex, final weights were significantly lower in undernourished males (74 +/- 3%) than females (90 +/- 5%), but weight gain was not significantly different between undernourished males (58 +/- 5%) and females (60 +/- 3%). Only in males did undernutrition significantly reduce costal diaphragm weight (to 77 +/- 5% of control). Diaphragm forces, normalized for cross-sectional area, were not significantly different from male or female control values. Fatigue resistance indexes (fatigue/baseline force) were increased at all stimulation frequencies in undernourished males but not in undernourished females. Costal diaphragm atrophy, involving types I and II fibers, occurred in undernourished males but not in undernourished females. In conclusion, despite long-term undernutrition reducing weight gain to similar levels in males and females (relative to control), there was excellent preservation of diaphragm weight, function, and structure in females but, although diaphragm atrophy occurred, there was preserved contractility and increased fatigue resistance in males.