Moon Y S, Park C S
Department of Nutritional Sciences, University of California, Berkeley, CA 94720, USA.
J Nutr. 1999 Jun;129(6):1156-60. doi: 10.1093/jn/129.6.1156.
A nutritionally-regulated compensatory growth regimen imposed during a growing period from prepuberty to gestation can significantly affect mammary development and subsequent lactation performance. The objectives of this study were as follows: 1) to determine whether a compensatory nutrition regimen enhances lactation potential for the first and second lactation cycles and 2) to determine the extent to which a compensatory nutrition regimen modulates cell proliferation, differentiation, and apoptosis and expression of genes in mammary tissues of female rats. Female Sprague-Dawley rats (n = 122, 35 d of age) were randomly assigned either to the control group, with free access to diet, or to a stair-step compensatory nutrition feeding regimen, with an alternating 2-2-3-3-wk schedule. The regimen began with an energy-restricted diet (40% restriction) for 2 wk, followed by the control diet for 2 wk; this step was then repeated at 3-wk intervals. Pups of dams from the compensatory nutrition regimen group gained more during mid-lactation than did control group pups. Mammary tissues were obtained from early (d 2) and late (d 19) lactating rats. Mammary tissue from the compensatory nutrition group exhibited increased cell proliferation and greater gamma-glutamyltranspeptidase and ornithine decarboxylase gene expressions than did tissue from the control group during early lactation of both cycles. Mammary tissue from the compensatory nutrition group also had fewer apoptotic cells than tissue from the control group during late lactation of the first lactation cycle. These results suggest that the compensatory nutrition regimen imposed during the peripubertal developmental phase stimulated mammary growth and enhanced lactation performance by affecting the expression of genes that regulate the cell cycle.
在从青春期前到妊娠期的生长阶段实施的营养调控补偿性生长方案，可显著影响乳腺发育及随后的泌乳性能。本研究的目的如下：1）确定补偿性营养方案是否能提高第一和第二泌乳周期的泌乳潜力；2）确定补偿性营养方案在多大程度上调节雌性大鼠乳腺组织中的细胞增殖、分化、凋亡及基因表达。将122只35日龄的雌性斯普拉格-道利大鼠随机分为两组，一组为对照组，可自由进食；另一组采用阶梯式补偿性营养喂养方案，按2-2-3-3周交替进行。该方案始于为期2周的能量限制饮食（限制40%），随后是2周的对照饮食；此步骤每隔3周重复一次。补偿性营养方案组母鼠的幼崽在泌乳中期比对照组幼崽增重更多。在泌乳早期（第2天）和晚期（第19天）获取大鼠的乳腺组织。在两个周期的泌乳早期，补偿性营养组的乳腺组织与对照组相比，细胞增殖增加，γ-谷氨酰转肽酶和鸟氨酸脱羧酶基因表达更高。在第一个泌乳周期的泌乳晚期，补偿性营养组的乳腺组织凋亡细胞也比对照组少。这些结果表明，在青春期前后发育阶段实施的补偿性营养方案通过影响调节细胞周期的基因表达，刺激了乳腺生长并提高了泌乳性能。
