Wagner J D, Zhang L, Greaves K A, Shadoan M K, Schwenke D C
Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA.
Metabolism. 2000 Sep;49(9):1188-96. doi: 10.1053/meta.2000.8620.
We have previously shown that soy protein consumption improves lipoprotein concentrations and reduces the progression of atherosclerosis in cynomolgus monkeys. The mechanism for these beneficial effects is unclear. The purpose of this study was to determine potential mechanisms for the atheroprotective effects of soy and to determine if these effects extend to diabetic monkeys. We designed an experiment with a 2 x 2 factorial design in which adult male monkeys (N = 23) were fed an atherogenic diet with a protein source of either soy isolate or casein and lactalbumin, and the monkeys were either control or streptozotocin-induced diabetic. Diabetics had significantly increased fasting glucose and glycated hemoglobin (GHb) levels; this relationship was not affected by the type of dietary protein. Diabetics also had increased total (TC) and low-density lipoprotein cholesterol (LDLC) concentrations. However, soy consumption significantly reduced TC and LDLC concentrations in both control and diabetic monkeys. Plasma and arterial LDL metabolism was determined by injecting 125I-LDL at 48 hours and 131I-tyramine cellobiose LDL at 1 hour prior to necropsy. This allowed a determination of the arterial LDL concentration, permeability, and arterial LDL delivery. An increase in the whole-body plasma LDL fractional catabolic rate (FCR) was found with soy. Soy significantly reduced the arterial LDL concentration across all arterial sites by an average of 50%. Soy also significantly reduced the delivery of LDLC to all arterial sites by an average of 40%. While this was primarily due to the lower plasma LDLC concentration, LDL permeability in the carotid bifurcation and internal carotid arteries was also reduced. There was no additional effect of diabetes. These beneficial effects on plasma and arterial LDL metabolism would be expected to reduce atherosclerosis and were found in both control and diabetic monkeys.
我们之前已经表明，食用大豆蛋白可改善食蟹猴的脂蛋白浓度，并减缓动脉粥样硬化的进展。这些有益作用的机制尚不清楚。本研究的目的是确定大豆对动脉粥样硬化保护作用的潜在机制，并确定这些作用是否也适用于糖尿病猴。我们设计了一项采用2×2析因设计的实验，其中成年雄性猴（N = 23）被喂食一种致动脉粥样硬化饮食，其蛋白质来源为大豆分离蛋白或酪蛋白和乳白蛋白，并且这些猴要么是对照猴，要么是经链脲佐菌素诱导的糖尿病猴。糖尿病猴的空腹血糖和糖化血红蛋白（GHb）水平显著升高；这种关系不受膳食蛋白质类型的影响。糖尿病猴的总胆固醇（TC）和低密度脂蛋白胆固醇（LDLC）浓度也有所升高。然而，食用大豆显著降低了对照猴和糖尿病猴的TC和LDLC浓度。在尸检前48小时注射125I-LDL以及在1小时前注射131I-纤维二糖酪胺LDL来测定血浆和动脉LDL代谢。这使得能够确定动脉LDL浓度、通透性以及动脉LDL输送情况。发现食用大豆可使全身血浆LDL分数分解代谢率（FCR）增加。大豆使所有动脉部位的动脉LDL浓度平均显著降低了50%。大豆还使LDLC向所有动脉部位的输送平均显著降低了40%。虽然这主要是由于血浆LDLC浓度较低，但颈动脉分叉处和颈内动脉的LDL通透性也降低了。糖尿病没有额外的影响。这些对血浆和动脉LDL代谢的有益作用预计会减轻动脉粥样硬化，并且在对照猴和糖尿病猴中均有发现。
