Prezant D J, Karwa M L, Richner B, Maggiore D, Gentry E I, Cahill J
Department of Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York 10467, USA.
J Appl Physiol (1985). 1997 Jan;82(1):125-33. doi: 10.1152/jappl.1997.82.1.125.
The effects of long-term dexamethasone treatment on diaphragm muscle were studied in female and male rats. Compared with pair-fed control animals, dexamethasone treatment did not significantly affect estrous cycling or peak serum estradiol levels; however, testosterone levels were significantly increased in females and decreased in males. Dexamethasone significantly reduced body and costal diaphragm weights, but to a lesser extent in females than in males. Reductions in diaphragm weight were proportional to reductions in body weight. In females and males, dexamethasone treatment significantly decreased diaphragm fiber (types I and II) cross-sectional area and the relative expression of myosin heavy chain isoform 2B. With the exception of type I fiber atrophy, these changes occurred to a lesser extent in females. Dexamethasone did not significantly affect specific forces. Dexamethasone significantly increased twitch one-half relaxation time and fatigue resistance indexes in males but not in females. In conclusion, the effects of long-term dexamethasone treatment were gender specific, with significantly fewer effects in females, and changes in serum testosterone levels were associated with these findings.
研究了长期地塞米松治疗对雌性和雄性大鼠膈肌的影响。与配对喂食的对照动物相比，地塞米松治疗对动情周期或血清雌二醇峰值水平没有显著影响；然而，雌性大鼠的睾酮水平显著升高，而雄性大鼠的睾酮水平则降低。地塞米松显著降低了体重和肋膈重量，但对雌性的影响程度小于雄性。膈肌重量的减轻与体重的减轻成正比。在雌性和雄性大鼠中，地塞米松治疗显著降低了膈肌纤维（I型和II型）的横截面积以及肌球蛋白重链亚型2B的相对表达。除了I型纤维萎缩外，这些变化在雌性中发生的程度较小。地塞米松对比肌力没有显著影响。地塞米松显著增加了雄性大鼠的抽搐半松弛时间和疲劳抵抗指数，但对雌性大鼠没有影响。总之，长期地塞米松治疗的影响具有性别特异性，对雌性的影响显著较少，血清睾酮水平的变化与这些发现有关。
