Glial glucocorticoid receptors in aged Fisher 344 (F344) and F344/Brown Norway rats.
Glucocorticoid receptors (GR) regulate glial function, and changes in astrocyte gene expression are implicated in age-related pathology. We evaluated changes in astroglial GR expression in two strains of rats--Fisher 344 (F344; 4, 12 and 24 months) and F344/Brown Norway strain (F344/BN; 4, 12 and 30 months). In both strains basal levels of corticosterone were higher in the oldest groups of rats. Age-related increases in GR (+) astrocytes but not the percent of astrocytes expressing GR were observed in the hippocampus CA1 region in F344 rats. Age-related decreases in CA1 GR (+) astrocytes and the percentage of GR (+) astrocytes were observed in the F344/BN strain only. Similar strain-specific changes were observed in the dentate gyrus. In the hypothalamic paraventricular nucleus: (1) F344 rats exhibited significant decreases in the overall number of glial profiles with age, (2) F344/BN rats exhibited decreases in the numbers of GR (+) astrocytes with aging and (3) the proportion of GR (+) astrocytes decreased in older F344/BN, but not F344 rats. Overall, the data demonstrate age- and strain-related alterations in GR astrocytic expression that may explain unique phenotypic differences in brain function observed in both strains.
Kasckow
J
J
VA Pittsburgh Health Care System (116A), Behavioral Health, 7180 Highland Dr. Pittsburgh, PA 15206, USA. kasckowjw@upmc.edu
Xiao
C
C
Herman
J P
JP
D000375:Aging / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D006624:Hippocampus / Q000378:metabolism*; D006854:Hydrocortisone / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D006854:Hydrocortisone