Levin S, Semler D, Ruben Z
Searle R&D, Skokie, Illinois 60077.
Toxicol Pathol. 1993;21(1):1-14. doi: 10.1177/019262339302100101.
This study was intended to identify changes caused by short-term reduced feed intake in rats such as may occur with unpalatable feed or other forms of anorexia. For 2 wk, groups of rats (10/sex/group) were fed ad libitum (control group) or given 75% (mildly restricted group), 50% (moderately restricted group), or 25% (severely restricted group) of the amount of feed eaten the day before by controls. The control group and mildly restricted group grew steadily, but the terminal body weights of the mildly restricted group (both males and females) were only about 80% of controls. The moderately restricted group did not grow during the first week but grew slightly during the second week (terminal body weights about 65% of control). The severely restricted group lost weight throughout the study (terminal weight about 40% of control). Restricted groups exhibited hemoconcentration directly related to the degree of feed restriction. White blood cell counts were reduced (principally due to lymphopenia) in severely restricted rats. Platelet counts were decreased in all restricted groups. Total serum protein concentration was reduced (decreased globulins) in all female restricted groups and in the severely restricted males. The severely restricted rats had increased serum bilirubin, electrolyte derangements, and (in females only) decreased cholesterol. Thymus and liver weights (absolute and relative) were decreased in the moderately and severely restricted groups. All the feed-restricted groups had an increased incidence of superficial gastric erosions. The mildly and moderately restricted groups had slightly decreased hematopoietic tissue in sternal bone marrow, while the severely restricted group had bone marrow necrosis, thymic atrophy, and mild testicular degeneration. Findings in the severely restricted group were distinct from those in the other groups on the basis of their severity and were considered adverse. Changes in the mildly and moderately restricted groups were considered adaptive and innocuous since feed restriction of this degree has historically been associated with increased longevity and decreased disease incidence in chronic studies.
本研究旨在确定短期饲料摄入量减少给大鼠带来的变化，这种情况可能因饲料不可口或其他形式的厌食症而发生。连续2周，将大鼠分成几组（每组雌雄各10只），一组自由采食（对照组），其余组分别给予相当于对照组前一天采食量75%（轻度限食组）、50%（中度限食组）或25%（重度限食组）的饲料。对照组和轻度限食组稳定生长，但轻度限食组（雌雄均是）的终末体重仅为对照组的约80%。中度限食组在第一周没有生长，但在第二周略有生长（终末体重约为对照组的65%）。重度限食组在整个研究过程中体重减轻（终末体重约为对照组的40%）。限食组出现与饲料限制程度直接相关的血液浓缩。重度限食大鼠的白细胞计数减少（主要由于淋巴细胞减少）。所有限食组的血小板计数均下降。所有雌性限食组以及重度限食雄性大鼠的血清总蛋白浓度降低（球蛋白减少）。重度限食大鼠的血清胆红素升高、电解质紊乱，且（仅雌性）胆固醇降低。中度和重度限食组的胸腺和肝脏重量（绝对重量和相对重量）均下降。所有限食组的浅表性胃糜烂发生率均增加。轻度和中度限食组胸骨骨髓造血组织略有减少，而重度限食组出现骨髓坏死、胸腺萎缩和轻度睾丸退化。重度限食组的结果在严重程度上与其他组不同，被认为是不良的。轻度和中度限食组的变化被认为是适应性的且无害，因为在长期研究中，这种程度的饲料限制历来与寿命延长和疾病发生率降低有关。
