Social stress increases blood pressure and cardiovascular pathology in a normotensive rat model.
Territorial stress (TS) elevates blood pressure (BP) in several mammalian species. However, cardiovascular pathology following chronic stress has not been consistently shown in a non-genetic hypertension model. Therefore, the hypothesis tested was that social stress would directly increase: BP, collagen deposition in coronary and mesenteric arteries, and myocardial fibrosis. Wistar-Kyoto (WKY) male rats, four weeks of age, were divided into one of three groups: controls (n = 9), territorial stress (TS, n = 12), and social isolation followed by territorial stress (SITS, n = 11). Blood pressure was measured biweekly, and blood samples biweekly for serum testosterone, corticosterone, epinephrine and norepinephrine. Blood pressure significantly increased in the TS (130 mmHg, p < 0.05) and SITS (150 mmHg, p < 0.05) groups, compared to controls (120 mmHg, ANOVA, F = 6.7, p < 0.001). Coronary collagen was increased 47% in the TS group and 90% in the SITS group compared to controls (p < 0.05). The coronary wall/lumen ratio increased significantly (45%, p < 0.05) in the SITS group compared to the controls. Myocardial fibrosis was increased 27% in the TS group and 74% in the SITS group compared to controls (p < 0.05). In conclusion, stress treatments increased BP and cardiac pathology in a normotensive rat strain.
Andrews
Ellen
E
Department of Biology, University of Akron, Akron, Ohio 44325-3908, USA.
Jenkins
Cathleen
C
Seachrist
Darcie
D
Dunphy
Gail
G
Ely
Daniel
D
D000311:Adrenal Glands / Q000033:anatomy & histology; D000818:Animals; D001795:Blood Pressure Determination; D003345:Corticosterone / Q000097:blood*; D004195:Disease Models, Animal; D004837:Epinephrine / Q000097:blood*; D006973:Hypertension / Q000097:blood / Q000209:etiology*; D007668:Kidney / Q000033:anatomy & histology; D016014:Linear Models; D008297:Male; D009929:Organ Size; D051381:Rats; D011921:Rats, Inbred WKY; D012931:Social Environment; D013315:Stress, Psychological / Q000097:blood / Q000150:complications*; D013737:Testis / Q000033:anatomy & histology
D003345:Corticosterone; D004837:Epinephrine