Nichols B L, McKee K, Putman M, Henry J F, Nichols V N
U.S. Department of Agriculture, Children's Nutrition Research Center, Houston, TX 77030.
J Pediatr Gastroenterol Nutr. 1989 Jan;8(1):102-9. doi: 10.1097/00005176-198901000-00019.
Lactoferrin has been identified as the factor in human colostrum that accounts for the increased incorporation of thymidine into DNA in a rat crypt enterocyte bioassay. Commercially available infant formulas used in the refeeding of infants who have severe dietary intolerance associated with mucosal atrophy were tested in this bioassay. In contrast to human milk, no stimulation was observed with these formulas in the assay. All formulas inhibited basal thymidine incorporation. The degree of inhibition of the basal assay progressed from 14% with cow's-milk formula to 30% with soy-based formulas to 45% with hydrolyzed casein formulas. When the formulas were supplemented with lactoferrin to match the level of that in human milk, the result was a 35% relative increase in thymidine incorporation into DNA. The quantitative level of response was primarily influenced by the baseline inhibitions associated with the specific formulas. The most profound effect was observed with the hydrolyzed casein formula, when lactoferrin supplementation reversed the baseline inhibition but did not result in a response greater than that seen in control basal bioassays. The supplementation of infant formulas with lactoferrin improved the thymidine incorporation in rat crypt enterocytes; a response equivalent to that of human milk, however, would require a redesign of other formula components to reduce basal inhibition.
乳铁蛋白已被确定为人类初乳中的一种因子，在大鼠隐窝肠细胞生物测定中，它可解释胸腺嘧啶核苷掺入DNA的增加。对用于喂养患有与黏膜萎缩相关的严重饮食不耐受的婴儿的市售婴儿配方奶粉进行了此项生物测定。与母乳不同，在该测定中未观察到这些配方奶粉有刺激作用。所有配方奶粉均抑制了基础胸腺嘧啶核苷掺入。基础测定的抑制程度从牛奶配方奶粉的14%，到大豆配方奶粉的30%，再到水解酪蛋白配方奶粉的45%逐渐增加。当配方奶粉添加乳铁蛋白以使其水平与母乳中的水平相匹配时，胸腺嘧啶核苷掺入DNA的量相对增加了35%。反应的定量水平主要受与特定配方奶粉相关的基线抑制的影响。水解酪蛋白配方奶粉的效果最为显著，添加乳铁蛋白可逆转基线抑制，但并未导致反应大于对照基础生物测定中的反应。给婴儿配方奶粉添加乳铁蛋白可改善大鼠隐窝肠细胞中胸腺嘧啶核苷的掺入；然而，要达到与母乳相当的反应，需要重新设计其他配方成分以减少基础抑制。
