Effects of ageing on microglia in the normal rat brain: immunohistochemical observations

Neuroreport. 1994 Jun 2;5(10):1224-6. doi: 10.1097/00001756-199406020-00016.


The numbers of ramified microglia stained by mouse monoclonal antibodies (OX-6 and X-42) in various regions of the brain were compared in the young (8 weeks) and aged (12 months) rats. OX-6-positive microglia increased in number with ageing, but OX-42-positive microglia did not. In both young and aged rats, the number of OX-6-positive microglia in white matter was higher than that in grey matter, but the number of OX-42-positive microglia in white matter was the same as that in grey matter. OX-42 stains microglia in both activated and resting states, whereas OX-6 stains mainly microglia in the activated state. Our findings suggest that microglia become activated with age-related changes, especially in white matter.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / pathology*
  • Animals
  • Antibodies, Monoclonal / immunology
  • Brain / cytology*
  • Brain / growth & development*
  • Cerebral Cortex / cytology
  • Cerebral Cortex / growth & development
  • Immunohistochemistry
  • Macrophage Activation / physiology
  • Major Histocompatibility Complex / immunology
  • Male
  • Mice
  • Microglia / physiology*
  • Rats
  • Rats, Wistar


  • Antibodies, Monoclonal