Litwin S E, Raya T E, Daugherty S, Goldman S
Department of Internal Medicine, Tucson Veterans Affairs Medical Center, Arizona 85723.
Am J Physiol. 1991 Sep;261(3 Pt 2):H836-42. doi: 10.1152/ajpheart.1991.261.3.H836.
Diabetes is believed to be associated with impaired systolic and diastolic function of the heart; however, some investigators have found that diabetic rats have increased cardiac output. We investigated changes in the peripheral circulation that could account for an increased cardiac output in diabetic rats (n = 30), 4 wk after a single tail vein injection of streptozotocin (60 mg/kg), and age-matched control rats (n = 31). Compared with controls, diabetic rats exhibited decreased (P less than 0.05) mean arterial pressure, characteristic aortic impedence, and total peripheral resistance; however, cardiac index and stroke volume index were increased. Aortic compliance, mean circulatory filling pressure, central venous pressure, pressure gradient for venous return, and venous compliance were unchanged in the diabetic rats compared with control. Baseline left ventricular end-diastolic pressure and end-diastolic volume were increased in the diabetic rats. Following a volume load of 30 ml/kg, cardiac index and stroke volume index increased less in the diabetic than in the control rats (35 vs. 102% and 69 vs. 105%, respectively). Thus, even with impaired systolic function, cardiac output is increased or maintained in diabetic rats because of the combination of decreased afterload and maintenance of preload.
糖尿病被认为与心脏收缩和舒张功能受损有关；然而，一些研究人员发现糖尿病大鼠的心输出量增加。我们研究了糖尿病大鼠（n = 30）在单次尾静脉注射链脲佐菌素（60 mg/kg）4周后外周循环的变化，这些变化可能解释糖尿病大鼠心输出量增加的原因，同时还研究了年龄匹配的对照大鼠（n = 31）。与对照组相比，糖尿病大鼠的平均动脉压、特征性主动脉阻抗和总外周阻力降低（P < 0.05）；然而，心脏指数和每搏量指数增加。与对照组相比，糖尿病大鼠的主动脉顺应性、平均循环充盈压、中心静脉压、静脉回流压力梯度和静脉顺应性均无变化。糖尿病大鼠的基线左心室舒张末期压力和舒张末期容积增加。在给予30 ml/kg的容量负荷后，糖尿病大鼠的心脏指数和每搏量指数的增加幅度小于对照大鼠（分别为35%对102%和69%对105%）。因此，即使存在收缩功能受损，由于后负荷降低和前负荷维持的共同作用，糖尿病大鼠的心输出量仍会增加或维持。
