THE EFFECTS OF VASECTOMY AND EXERCISE UPON ARTERIAL EXTENSIBILITY AND THE EXTENT AND SEVERITY OF ATHEROSCLEROSIS

The purpose of this study was to investigate the effects of vasectomy on both arterial extensibility and the extent and severity of atherosclerosis in Lewis strain rats. A second purpose was to determine if planned periodic exercise conditioning had an inhibitory or prophylactic effect upon atherosclerotic development. Forty rats received vasectomies, 20 rats received sham-vasectomies, and 26 rats served as controls. Half of each of these three groups were assigned to an exercise group or a sedentary group. All 86 rats were randomly selected before assignment to these six groups and fed an atherogenic diet throughout the experimental period.;Based on the findings and analysis of data the following conclusions were drawn: (1) Vasectomy did not play an etiological role in inducing or exacerbating atherosclerosis as demonstrated by extent and severity and arterial extensibility measures. (2) Exercise did not prevent or inhibit the occurrence or extent and severity of atherosclerosis. (3) Exercise maintained or prevented diminished extensibility for only two of eight measures of arterial extensibility. (4) One of these extensibility measures was stretch distance at breaking point, and it was found that the control sedentary group had significantly greater aortic extensibility than the sham-vasectomized sedentary group. The vasectomized and sham-vasectomized exercise groups had significantly greater extensibility than the vasectomized and sham-vasectomized sedentary groups. (5) The other measure of arterial extensibility was breaking load (stiffness), and it was found that the exercise groups had significantly greater extensibility than did sedentary groups.;Aortic extensibility involving stiffness and stretch distance measures was determined by means of an Instron Testing Instrument subsequent to 14 weeks of exercise conditioning on a small animal treadmill. Extent and severity of atherosclerosis were determined following gross inspection and visual grading using a 1 to 5 Likert-like scale. All data from this 2 x 3 factorial design were analyzed by the use of the two-way analysis of variance method with further comparisons made by Scheffe's Multiple Comparison Test.