Age-related changes in rat brain capillaries.
We have measured several morphological parameters by electron microscopy of the frontal cortex (FC) and hippocampal CA1 (HC) capillaries in male Fischer 344 rats 3-, 9- and 24-months old. The results indicate that with increasing age there is an increase in the cross-sectional area of the basement membrane, increase in the fraction of endothelial cell and pericyte cytoplasmic area occupied by mitochondria in the FC, increase in the size of the pericyte mitochondria in both the FC and HC, increased capillary lumen area in the FC and decreased capillary lumen area in the HC. Also, the cytoplasmic area occupied by mitochondria in capillary pericytes is larger than in the endothelial cells of both FC and HC. These results suggest that there is regional variation in the age-associated changes in capillary morphometrics.
D000375:Aging; D000818:Animals; D002196:Capillaries / Q000033:anatomy & histology* / Q000166:cytology / Q000648:ultrastructure; D002560:Cerebrovascular Circulation; D008297:Male; D008854:Microscopy, Electron; D008928:Mitochondria / Q000648:ultrastructure; D051381:Rats; D011916:Rats, Inbred F344