Royland J, Klinkhachorn P, Konat G, Wiggins R C
Department of Anatomy, West Virginia University, School of Medicine, Morgantown 26506.
Neurochem Int. 1992 Sep;21(2):269-74. doi: 10.1016/0197-0186(92)90157-m.
This study employs a large population of developing rats designed to range continuously from above a normal, average weight to severely undernourished. The purpose of the study is to determine if brain myelin development is vulnerable to mild growth retardation from chronic hunger, or if brain myelin development is altered only after a certain tolerable amount of growth retardation is exceeded. The brains were examined at a landmark age, weaning, since myelination is one of the most vulnerable features of brain development and its rate of synthesis is highest at this age. Brain size was logarithmically related to body weight, and brain growth retardation increased as the severity of food deprivation increased. There was an additional reduction in the concentration of brain myelin. In contrast to brain weight, the reduction in myelin concentration was linearly related to body size over the full range from well nourished to undernourished. From a population perspective, these data indicate growth retardation from undernourishment in any amount slows brain growth and additionally lowers the concentration of brain myelin; however, individuals, in both well nourished and undernourished groups, vary widely. Implications and cautions of extrapolation to human populations are discussed.
本研究使用了大量处于发育阶段的大鼠，其体重范围从高于正常平均体重到严重营养不良。该研究的目的是确定脑髓鞘发育是否易受慢性饥饿导致的轻度生长迟缓影响，或者脑髓鞘发育是否仅在超过一定可耐受的生长迟缓量后才会改变。由于髓鞘形成是脑发育最易受影响的特征之一，且其合成速率在断奶这个标志性年龄时最高，因此在断奶这个标志性年龄对大脑进行了检查。脑大小与体重呈对数关系，并且随着食物剥夺程度的加重，脑生长迟缓加剧。脑髓鞘浓度进一步降低。与脑重量不同，在从营养良好到营养不良的整个范围内，髓鞘浓度的降低与身体大小呈线性关系。从总体角度来看，这些数据表明，任何程度的营养不良导致的生长迟缓都会减缓脑生长，并进一步降低脑髓鞘浓度；然而，营养良好和营养不良组中的个体差异都很大。本文讨论了将这些结果外推至人类群体的意义和注意事项。
