Effects of prenatal protein malnutrition and acute postnatal stress on granule cell genesis in the fascia dentata of neonatal and juvenile rats

Although postnatal genesis of granule cells in the hippocampal fascia dentata is known to be influenced by prenatal protein deprivation or by stress, the combined effects of prenatal protein malnutrition and stress on these cells are unknown. This study was designed to examine this combined effect. Well-nourished and prenatally malnourished pups on postnatal day 7 (P7) were stressed by maternal separation and reduction of body temperature and on postnatal day 30 (P30) by immobilization with restraint. Bromodeoxyuridine (BrDU) was injected at the time of stress, and 2 It later, the numbers of immunolabeled cells were quantified by standard stereological techniques. In comparison to controls, prenatally malnourished rats showed a significantly lower number of cells tagged in the fascia dentata on P7 (p less than or equal to 0.05), and a significantly higher number of cells (p less than or equal to 0.05) on P30. In both age groups, control rats exposed to acute stress showed a significantly decreased number of cells tagged in the fascia dentata (p less than or equal to 0.05). In contrast, neurogenesis in malnourished rats was not significantly affected by acute stress at either age. Thus, the pattern of neurogenesis in the fascia dentata and its response to stress has been fundamentally altered by prenatal protein deprivation. (C) 2004 Elsevier B.V. All rights reserved.