摘要
目的观察机械通气（MV）后大鼠膈肌和比目鱼肌的形态学变化，初步探讨失用性膈肌和骨骼肌功能障碍的机制。方法将16只雄性SD大鼠按随机数字表法分为对照组和MV组，每组8只。MV组大鼠采用控制性通气，并维持麻醉；对照组仅麻醉大鼠，不予MV和维持麻醉。通气18h后取膈肌和比目鱼肌，光镜下观察膈肌和比目鱼肌组织形态学改变；采用免疫荧光法观察肌纤维横截面变化，并计算肌纤维横截面积；透射电镜下观察肌纤维超微结构改变。结果①光镜下显示：对照组膈肌和比目鱼肌纤维横截面形态规则，细胞核分布正常，胞质染色均匀。MV组膈肌纤维横截面较对照组缩小，但坏死和炎性细胞浸润不明显；而比目鱼肌大体形态与对照组无明显差异。②荧光显微镜下显示：对照组膈肌慢缩肌纤维横截面较小，而快缩肌纤维横截面较大。MV组膈肌慢缩肌纤维和快缩肌纤维横截面积均较对照组明显减小（μm^2：1069．00±155．24比1297．12±331．15，2279．66±442．31比3031．80±596．11，均P〈0．05）；由于快缩肌纤维横截面积减小更为显著，因此MV组膈肌慢缩肌纤维横截面积占总面积百分比明显高于对照组[（29．58±3．61）％比（24．35±2．48）％]，快缩肌纤维横截面积占总面积百分比较对照组明显降低[（70．42±3．61）％比（75．63±2．48）％，均P〈0．01]。对照组比目鱼肌慢缩肌纤维和快缩肌纤维横截面积与MV组比较则无明显差异（μm^2：3193．80±559．36比3008．84±559．22，3392．86±514．56比3594．35±651．67，均P〉O．05）。③透射电镜下显示：对照组膈肌和比目鱼肌纤维排列整齐，明暗带界线及“Z线”清晰，视野下未见自噬体；线粒体外膜完整，嵴呈隔板状，内膜内基质电子密度均匀。MV组膈肌部分肌纤维排列紊乱，“Z线”模糊或断裂，自噬体生成数量增加，部
Objective To investigate the structural response of diaphragm and soleus of the rat after mechanical ventilation （MV）, and to explore the specific mechanism of the dysfunction of both muscles. Methods Sixteen male Sprague-Dawley （SD） rats were randomly divided into control group and MV group, with 8 rats in each group. Rats in MV group were treated with controlled ventilation and maintained anesthesia, and those in control group were only anesthetized without MV and maintained anesthesia. The diaphragm and soleus were harvested after MV for 18 hours, and the morphology changes were observed with light microscope. The cross section of muscle fiber was observed by immnnofluorescenee technique analysis, and the cross-sectional area of muscle fiber was calculated. The ultra structural changes in muscle fibers were observed under transmission electron microscope. Results （1） Observed under light microscope, the cross section of the diaphragm and soleus muscle in the control group was regular, the nucleus was normal and the cytoplasm was homogeneous. The fibers in the diaphragm-biopsy specimens from MV subjects were smaller than those from control subjects, whereas these signs were not found in soleus. But fiber atrophy in MV specimens was not accompanied by an inflammatory-cell infiltrate.（2） Under the fluorescence microscope, the control group had a smaller cross-section of the slow-twitch muscle in diaphragm, while the fast-twitch muscle fibers were larger. As compared with diaphragm-biopsy specimens from control, specimens from MV subjects showed decreased cross-sectional areas of slow-twitch and fast-twitch fibers, respectively （μm^2：1069.00± 155.24 vs. 1 297.12 ± 331.15, 2279.66±442.31 vs. 3031.80±596.11, both P 〈 0.05）. The disproportionate decrease in fast-twitch fibers crosssectional areas [（70.42 ± 3.61）% vs. （75.63 ± 2.48）%] resulted in an increase in the percentage of total area occupied by the slow-twitch fibers [（29.58 ± 3.61）% vs. （24.35 ± 2.48）%, both P �
出处
《中华危重病急救医学》
CAS
CSCD
北大核心
2017年第1期11-15,共5页
Chinese Critical Care Medicine
基金
上海市自然科学基金（16ZR1432900）
关键词
膈肌
比目鱼肌
机械通气
肌萎缩
自噬
Diaphragm
Soleus
Mechanical ventilation
Atrophy
Autophagy
