Undernutrition and the Developing Cerebellar Cortex in the Rat

Abstract

Undernutrition of the newborn rats, produced during the first 3 weeks by increasing the litter size and restricting the mother's diet, resulted in reduction of the body and brain weights of the experimental animals. One group of undernourished animals showed especially severe reduction of body and cerebellar weights. These animals, on the 10th postnatal day, had an immature cerebellar cortex corresponding to that of the 7th day postnatal control animals. The external granular layer persisted in the cerebellar cortex of the underweight animals until the 23rd day, while it disappeared by 20th day in the control animals. Mitotic activity was evident until the 21st postnatal day in these animals while it stopped in the normal animal by 16th postnatal day. There was no marked difference in the fine structure of the various cell types in the control and undernourished animals. Midsagittal tracings of the cerebellar cortex showed a reduced surface area in the undernourished animals, while the thickness of the external granular layer and molecular layer did not show any significant difference when compared to that of the control animals, thus showing a reduction in total cell number, but not per unit area. The normal morphological appearance of the cerebellar cortex in the underfed animals of higher weight probably indicates that these animals are adequately nourished in spite of the reduction in weight when compared to the control animals, which probably are overfed.

Ultrastructural Changes in the Developing Rat Cerebellum in Chronic Undernutrition

“…The present study confirmed that undernutrition, induced by increased litter size, resulted in marked reduction of the body weights of the suckling rats, comparable to that reported by Bass et al (1970), Neville & Chase (1971, and Gopinath, Bijlani & Deo (1976). The morphologic sequelae of inadequate nutrition were manifested mainly in the neuronal cell processes and in the neuroglial elements of the undernourished rats, whereas little or no changes occurred in the perikarya of the various neurons.…”

“…A substantial body of experimental evidence has accumulated which indicates that undernutrition severely retards cerebellar growth. This is manifested by a reduction in cell numbers (Winick & Noble, 1966;Barnes & Altman, 1973;Patel, Balazs & Johnson, 1973;Gopinath et al, 1976), delayed enzymatic development (Persson & Sima, 1975), impaired myelination (Bass et al, 1970Hedley-Whyte & Meuser, 1971), stunting of Purkinje cell dendrites, and an overall decrease in the neuropil (Neville & Chase, 1971;Sima & Persson, 1975). The size and morphology of the perikarya of individual neurons were apparently unaffected.…”

Neuropathology of phenylacetate poisoning in rats: An experimental model of phenylketonuria

“…An uneven growth rate, contributing to formation of an irregular extension of the granular cell layer into the molecular layer, was considered to be the reason for formation of multiple small subdivisions in the cerebellum of a patient with vitamin B, dependency and of rats with vitamin B, deficiency [39, 42, 431. Postnatal undernutrition has also caused a reduction in size of the cerebellar vermis of suckling rats [8,191. However, the irregular lobulation seen in the cerebellar vermis of the phenylacetate-treated animals was not observed in neonatal undernourished rats [22]. The reduction (65%) and rapid drop of body weight in undernourished rats [ 3 2 , 561 was not found in the phenylacetate-treated rats (see Table 1).…”

“…Both cerebellar and retinal neurons of postnatally treated rats are vulnerable to the adverse effects of phenylacetate. Morphological changes observed in the cerebellum, retina, and optic nerve of treated animals during the fourth to twenty-first days of life consist of regional reduction in the size of cerebellar vermis lobules IV, V, VIa, and 14, 18, 19, 2 5 , 34, 401, but [14, 15,21,22,28,41,47,49, 551 have been described. Recently, whorls of membranous materials were found in the oligodendroglial cells in brains from two PKU patients and were called "PKU bodies" [451.…”

Brain development, environment and sex: what can we learn from studying graviperception, gravitransduction and the gravireaction of the developing CNS to altered gravity?

“…The possibility that the observed changes in cerebellar mass are merely due to differences in tissue hydration can be dismissed in light of earlier observations (138) indicating that long exposure to increased gravity results in increased tissue hydration. Furthermore, while nutrition during early development affects CNS development (139) additional data seems to argue against the direct contribution of maternal undernutrition to the effect of hypergravity on the developing CNS. First, during lactation, despite lower food consumption, HG dams gained significantly more body mass than SC dams.…”