Myocyte Growth without Physiological Impairment in Gradually Induced Rat Cardiac Hypertrophy
Myocyte Growth without Physiological Impairment in Gradually Induced Rat Cardiac Hypertrophy
复制标题
逐渐诱导的大鼠心脏肥大中心肌细胞的生长无生理损伤
作者：
F. Julian;D. Morgan;R. Moss;M. González;P. Dwivedi
开发了一种手术技术，用于在幼龄大鼠（约1个月大，体重100 g）的肺动脉周围放置缝线。随着手术大鼠的生长，肺动脉逐渐收缩，导致4-6周后出现严重的右心室肥大，游离壁重量约为对照大鼠的两倍。没有心力衰竭或心脏失代偿的迹象。胶原蛋白浓度在手术组和对照组大鼠中是相同的。通过酶消化从右心室分离肌细胞。放射自显影研究显示在非肌细胞核中有相当大的摄取。肌细胞肌节长度不变。然而，肌细胞长度和面积增加足以解释观察到的游离壁重量增加。对随后固定的离体乳头肌和心室束进行生理学研究。在每个分离的肌肉中测量在最佳长度下的力产生能力、主动顺应性的大小和缩短的最大速度（使用四种不同的技术）。手术组和对照组大鼠之间未观察到显著变化。肌肉横截面的显微镜检查证实，从手术大鼠获得的肌肉中的平均肌细胞面积显著增加。结果表明，它是可能的，以获得相当大的增加，平均肌细胞的大小（约一个因素！）同时还能保持正常的生理功能。
A surgical technique was developed to place sutures around the pulmonary arteries of young rats (about 1 month old and 100 g body weight). As the operated rats grew, the pulmonary arteries were gradually constricted, leading after 4–6 weeks to the development of severe right ventricular hypertrophy with free wall weights about twice those from control rats. There were no signs of heart failure or cardiac decompensation. Collagen concentrations were the same in operated and control rats. Myocytes were isolated from right ventricles by enzymatic digestion. Autoradiographic studies showed considerable uptake In non-myocyte nuclei. Myocyte sarcomere lengths were unchanged. However, myocyte lengths and areas increased sufficiently to account for the increase in free wall weights observed. Physiological studies were done on isolated papillary muscles and ventricular strands, which were subsequently fixed. The force-generating capability at optimum length, magnitude of active compliance, and maximum speed of shortening (using four different techniques) were measured in each isolated muscle. There were no significant changes observed between operated and control rats. Microscopic examination of the muscle cross-sections confirmed that average myocyte area in the muscles obtained from operated rats was significantly increased. The results show that it is possible to obtain considerable increases in average myocyte size (by about a factor of !) while still maintaining normal physiological function.