Effects of the β2-adrenergic agonist clenbuterol on capillary geometry in cardiac and skeletal muscles in young and middle-aged rats
Effects of the β2-adrenergic agonist clenbuterol on capillary geometry in cardiac and skeletal muscles in young and middle-aged rats
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β2-肾上腺素能激动剂克伦特罗对中青年大鼠心肌和骨骼肌毛细血管几何结构的影响
DOI：
10.1046/j.1365-201x.1997.00236.x
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
T. Koyama
中科院分区：
文献类型：
--
作者：
J. Suzuki;M. Gao;Z. Xie;T. Koyama
在年轻（10周龄）和中年（37周龄）雄性Wistar大鼠中，研究了10天克伦特罗给药对心脏和骨骼肌毛细血管的影响，特别是在小动脉和小静脉毛细血管及其毛细血管密度的分布方面。实验组大鼠喂饲含盐酸克仑特罗2 mg·kg-1的饲料。在年轻和中年大鼠中，克伦特罗治疗增加了体重以及心脏和后肢肌肉的重量。左心室、比目鱼肌、跖肌、腓肠肌深、浅部肌纤维平均截面积均较治疗前明显增加（P < 0.01）。在左心室，总毛细血管密度和微静脉毛细血管密度在年轻大鼠（分别为9%和13%）和中年大鼠（分别为10%和11%）治疗后均降低。在所有检查的骨骼肌中也观察到总毛细血管密度降低。在年轻和中年大鼠中，左心室和骨骼肌中的毛细血管与纤维（C：F）比率和每个毛细血管的比例在治疗后均未发生变化。克伦特罗显著降低骨骼肌琥珀酸脱氢酶活性（P < 0.01）。这些结果表明，克伦特罗增加了左心室和骨骼肌中氧气的扩散距离。这些变化可能会减少组织的氧气供应，增加肌肉疲劳。
The effects of 10 day clenbuterol administration on cardiac and skeletal muscle capillarities were studied, particularly in terms of the distribution of arteriolar and venular capillaries and their capillary density, in young (10-week-old) and middle-aged (37-week-old) male Wistar rats. Rats of the treated groups were fed a diet containing 2 mg kg -1 clenbuterol hydrochloride. In both young and middle aged rats, clenbuterol treatment increased the body wt and the weights of the heart and hindlimb muscles. The mean fibre cross-sectional area was significantly increased after the treatment in the left ventricle, soleus, plantaris and both deep and superficial portions of gastrocnemius (P < 0.01). In the left ventricle, the total capillary density and the density of venular capillaries were decreased after the treatment in both young (9 and 13%, respectively) and middle-aged rats (10 and 11%, respectively). A decrease in total capillary density was also observed in all skeletal muscles examined. In both young and middle-aged rats, the capillary-to-fibre (C:F) ratio and the proportion of each capillary did not change after the treatment in both the left ventricle and skeletal muscles. Clenbuterol significantly decreased the activity of succinate dehydrogenase in all skeletal muscles examined (P < 0.01). These results suggest that clenbuterol increased the diffusion distance for oxygen in the left ventricle and skeletal muscles. These changes may reduce the oxygen supply to tissues and increase muscle fatigability.