The role of psychosocial factors in the development of arteriosclerosis in CBA mice: Observations on the heart, kidney and aorta

Approximately 300 mixed male and female CBA mice were exposed to 6 months of social confrontation in intercommunicating population cages. Histological sections were scored for severity of the ensuing acute and chronic interstitial nephritis, of glomerular mesangial changes, of myocardial fibrosis, and of arteriosclerotic degeneration of the intramural coronary vessels and of the aorta. The severity of the changes was contrasted with those found in a control group of the same or greater age in which sexes were separated and the living conditions were arranged to avoid confrontation. The accuracy of the scoring technique was shown to be sufficient to differentiate the severity of the various lesions; and in all of the conditions studied, significantly higher scores were obtained in the socially stimulated group.