Kris-Etherton P M, Layman D K, York P V, Frantz I D
J Nutr. 1979 Jul;109(7):1244-57. doi: 10.1093/jn/109.7.1244.
In two experiments, young rats were preconditioned with dietary cholesterol by: 1) nursing from dams with a high cholesterol milk or, 2) receiving 10 mg cholesterol dissolved in 0.5 ml of corn oil daily from 6 to 30 days of age. When rats preconditioned with dietary cholesterol in early life were fed stock diet supplemented with 10% lard and 0.5% cholesterol ("cholesterol challenge diet") there was no protection against dietary induced hypercholesterolemia in adult life. In a third experiment, two groups of newborn rats were intubated with: 1) a cholesterol free formula, 2) the cholesterol free formula plus 50 mg% cholesterol. A third group of pups suckled normally. After weaning all pups were fed a stock diet supplemented with 10% lard and 0.5% cholesterol for 1 month. There was no difference in the serum cholesterol in either group of artificially reared rats after the "cholesterol challenge" (106 +/- 6 mg/100 ml). Suckled rats, however, had a lower serum cholesterol after the "cholesterol challenge" (75 +/- 2 mg/100 ml). All experiments conducted refute the hypothesis that early exposure to dietary cholesterol protects against dietary induced hypercholesterolemia in adult life. It appears, however, that cholesterol metabolic systems are affected in early life because of the decreased ability of artificially reared rats to handle a "cholesterol challenge." Possible factors include a component of the dam's milk, growth and development, and the psychological and emotional stress of the artificial rearing process.
在两项实验中，对幼鼠进行膳食胆固醇预处理的方式如下：1）由食用高胆固醇乳汁的母鼠哺育；2）在6至30日龄期间，每日接受溶解于0.5毫升玉米油中的10毫克胆固醇。当在生命早期经膳食胆固醇预处理的大鼠喂食补充了10%猪油和0.5%胆固醇的基础饲料（“胆固醇激发饲料”）时，成年后对膳食诱导的高胆固醇血症并无保护作用。在第三项实验中，两组新生大鼠通过以下方式插管喂食：1）无胆固醇配方奶；2）无胆固醇配方奶加50毫克%胆固醇。第三组幼鼠正常哺乳。断奶后，所有幼鼠均喂食补充了10%猪油和0.5%胆固醇的基础饲料1个月。在“胆固醇激发”后，两组人工饲养的大鼠血清胆固醇并无差异（106±6毫克/100毫升）。然而，哺乳的大鼠在“胆固醇激发”后的血清胆固醇较低（75±2毫克/100毫升）。所有进行的实验均反驳了早期接触膳食胆固醇可保护成年后免受膳食诱导的高胆固醇血症影响这一假说。然而，似乎胆固醇代谢系统在生命早期受到影响，因为人工饲养的大鼠应对“胆固醇激发”的能力下降。可能的因素包括母鼠乳汁的成分、生长发育以及人工饲养过程中的心理和情感压力。
