Kayar S R, Banchero N
Respir Physiol. 1985 Jan;59(1):1-14. doi: 10.1016/0034-5687(85)90013-1.
Capillarity and fiber cross-sectional areas were measured in the hearts of guinea pigs exposed to cold early during growth. Twelve male guinea pigs were kept at 5 +/- 1 degrees C for 4-18 weeks. Hearts were perfusion fixed via the aorta with a 2.5% glutaraldehyde, 1% formaldehyde-buffered solution, blocks were cut from left (LV) and right (RV) ventricles, post-fixed in OsO4, dehydrated and embedded in Spurr medium. Blocks were cut transversely to fiber orientation, 0.5 micron thick, stained with Toluidine Blue and photographed at 400 x. Heart weights, number and location of capillaries and fiber cross-sectional areas (FCSA) were measured in cold-acclimated animals and in normothermic controls. Growth rates for all guinea pigs were similar. Acclimation to cold caused modest LV and RV hypertrophy. The greater LV weight seemed due to longer fibers of normal FCSA, whereas the greater RV weight was due to larger FCSA. Capillary density, capillary-to-fiber ratio and number of capillaries around the fibers were similar in the two groups of animals. Mean and maximal diffusion distances in cold-acclimated animals were not different from controls. Thus the myocardial hypertrophy induced by chronic volume overload was fully compensated for by increases in capillarity commensurate with increases in fiber girth.
在生长早期暴露于寒冷环境的豚鼠心脏中测量了毛细血管和纤维横截面积。12只雄性豚鼠在5±1摄氏度的环境中饲养4 - 18周。通过主动脉用2.5%戊二醛、1%甲醛缓冲溶液进行心脏灌注固定，从左心室（LV）和右心室（RV）切取组织块，用四氧化锇后固定，脱水并包埋在Spurr培养基中。将组织块垂直于纤维方向切成0.5微米厚，用甲苯胺蓝染色并在400倍下拍照。在冷适应动物和常温对照动物中测量心脏重量、毛细血管数量和位置以及纤维横截面积（FCSA）。所有豚鼠的生长速率相似。冷适应导致左心室和右心室轻度肥大。左心室重量增加似乎是由于正常FCSA的纤维更长，而右心室重量增加是由于FCSA更大。两组动物的毛细血管密度、毛细血管与纤维的比例以及纤维周围的毛细血管数量相似。冷适应动物的平均和最大扩散距离与对照组没有差异。因此，慢性容量超负荷诱导的心肌肥大通过与纤维周长增加相称的毛细血管增加而得到完全代偿。
