Hollenberg M, Honbo N, Samorodin A J
Am J Physiol. 1977 Sep;233(3):H356-60. doi: 10.1152/ajpheart.1977.233.3.H356.
Rats reared in litters of 18, 12, and 6 to determine whether preweanling nutritional state would alter rates of cardiac cell division, weighed 31.7, 39.1, 48.2 g, respectively, at 21 days of age. Weights of left ventricles also increased (93.2, 123.5, and 167.2 mg) as did those of right ventricles (29.9, 43.2, and 54.3 mg). Total DNA content rose in both ventricles in the pups reared 6 per litter vs. those reared 18 per litter (6/litter vs. 18/litter), but more so in the left ventricle (79%) than in the right (24%). Autoradiography confirmed that this increase in ventricular DNA resulted from increased proliferation of cardiac muscle cells, fibroblasts, and vascular endothelial cells. When 3H-labeled thymidine was injected on day 1, autoradiographs prepared on day 21 reflected an increased dilution of label in the 6/litter rats, consistent with enhanced proliferation. The labeling index and grains per nucleus of left ventricular muscle cells of the 6/litter rats were 29% (P less than 0.005) and 20% (P less than 0.001) less than those of the 18/litter rats. Less vigorous but definite hyperplasia occurred in the right ventricle, which appeared to respond with an increase more in cell size than in cell number.
将大鼠饲养在每窝18只、12只和6只的环境中，以确定断奶前的营养状态是否会改变心脏细胞的分裂速率。在21日龄时，这些大鼠的体重分别为31.7克、39.1克和48.2克。左心室重量也增加了（分别为93.2毫克、123.5毫克和167.2毫克），右心室重量同样增加了（分别为29.9毫克、43.2毫克和54.3毫克）。与每窝饲养18只的幼崽相比，每窝饲养6只的幼崽的左右心室总DNA含量均有所上升，但左心室上升幅度更大（79%），右心室上升幅度较小（24%）。放射自显影证实，心室DNA的这种增加是由于心肌细胞、成纤维细胞和血管内皮细胞的增殖增加所致。在第1天注射3H标记的胸腺嘧啶核苷后，第21天制备的放射自显影片显示，每窝6只的大鼠中标记的稀释度增加，这与增殖增强一致。每窝6只的大鼠左心室肌细胞的标记指数和每核颗粒数分别比每窝18只的大鼠低29%（P<0.005）和20%（P<0.001）。右心室发生了不太明显但确定的增生，其似乎更多地表现为细胞大小的增加而非细胞数量的增加。
