Effects of chronic malnourishment and aging on the ultrastructure of pyramidal cells of the dorsal hippocampus.
OBJECTIVE
Malnourishment (M) produces permanent alterations during the development of the CNS and might modify the aging process. In pyramidal neurons (PN) of the hippocampus, which are associated with learning and memory performance, few studies have focused on changes at the subcellular level under chronic malnutrition (ChM) in young (Y, 2 months old) and aged (A, 22 months old) rats. The present work evaluated the extent to which ChM disrupts organelles in PN of the dorsal hippocampus CA1 as compared to controls (C).


METHODS
Ultrastructural analysis was performed at 8000×  and 20 000×  magnification: Nucleus eccentricity and somatic, cytoplasmic, and nuclear areas were measured; and in the PN perikaryon, density indices (number of organelles/cytoplasmic area) of Golgi membrane systems (GMS, normal, and swollen), mitochondria (normal and abnormal), and vacuolated organelles (lysosomes, lipofuscin granules, and multivesicular bodies (MVB)) were determined.


RESULTS
The density of abnormal mitochondria, swollen GMS, and MVB increased significantly in the AChM group compared to the other groups. The amount of lipofuscin was significantly greater in the AChM than in the YChM groups - a sign of oxidative stress due to malnutrition and aging; however, in Y animals, ChM showed no effect on organelle density or the cytoplasmic area. An increased density of lysosomes as well as nucleus eccentricity was observed in the AC group, which also showed an increase in the cytoplasmic area.


CONCLUSIONS
Malnutrition produces subcellular alterations in vulnerable hippocampal pyramidal cells, and these alterations may provide an explanation for the previously reported deficient performance of malnourished animals in a spatial memory task in which aging and malnutrition were shown to impede the maintenance of long-term memory.
a Departamento de Neurobiología del Desarrollo y Neurofisiología , Instituto de Neurobiología Campus UNAM-Juriquilla , Boulevard Juriquilla 3001, Querétaro 76230 , Mexico.
Susana Angelica
SA
Castro-Chavira
a Departamento de Neurobiología del Desarrollo y Neurofisiología , Instituto de Neurobiología Campus UNAM-Juriquilla , Boulevard Juriquilla 3001, Querétaro 76230 , Mexico.
Azucena Ruth
AR
Aguilar-Vázquez
a Departamento de Neurobiología del Desarrollo y Neurofisiología , Instituto de Neurobiología Campus UNAM-Juriquilla , Boulevard Juriquilla 3001, Querétaro 76230 , Mexico.
Yvonne
Y
Martínez-Chávez
a Departamento de Neurobiología del Desarrollo y Neurofisiología , Instituto de Neurobiología Campus UNAM-Juriquilla , Boulevard Juriquilla 3001, Querétaro 76230 , Mexico.
Lourdes
L
Palma
a Departamento de Neurobiología del Desarrollo y Neurofisiología , Instituto de Neurobiología Campus UNAM-Juriquilla , Boulevard Juriquilla 3001, Querétaro 76230 , Mexico.
Euridice
E
Padilla-Gómez
a Departamento de Neurobiología del Desarrollo y Neurofisiología , Instituto de Neurobiología Campus UNAM-Juriquilla , Boulevard Juriquilla 3001, Querétaro 76230 , Mexico.
Sofia
S
Diaz-Cintra
D000375:Aging; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D053145:Cell Nucleus Size; D018753:Diet, Protein-Restricted / Q000009:adverse effects; D004195:Disease Models, Animal; D005260:Female; D006130:Growth Disorders / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D006624:Hippocampus / Q000378:metabolism / Q000648:ultrastructure*; D007774:Lactation; D008062:Lipofuscin / Q000378:metabolism; D008297:Male; D039382:Maternal Nutritional Physiological Phenomena; D046529:Microscopy, Electron, Transmission; D015388:Organelles / Q000378:metabolism / Q000648:ultrastructure; D018384:Oxidative Stress; D018812:Paternal Exposure / Q000009:adverse effects; D011247:Pregnancy; D011488:Protein Deficiency / Q000503:physiopathology*; D017966:Pyramidal Cells / Q000378:metabolism / Q000648:ultrastructure*; D017207:Rats, Sprague-Dawley; D015430:Weight Gain
D015415:Biomarkers; D008062:Lipofuscin
Aging; Electron microscopy; Hippocampus; Malnourishment; Pyramidal neurons