Abstract 1210: Preventive Exercise Decreases Blood Pressure and Modifies Atherosclerotic Plaque Phenotype in LDL Receptor Knockout Mice
Background: Our knowledge that exercise exerts beneficial effects on atherosclerotic disease is mainly based on epidemiological studies. Mechanisms involved in these effects, however, are not completely understood.
Aim: The objective of this study was to evaluate the effect of therapeutic and preventive exercise on atherosclerotic plaque development in an experimental model of atherosclerosis.
Methods: LDL receptor knockout (LDLr −/ −) male mice were fed a high fat and cholesterol diet and randomly divided in four groups. Therapeutic group (TF) started exercise protocol after 14 weeks of diet intake, while preventive group (PF) started diet and exercise simultaneously. Control groups did not exercise: TFC (TF sedentary control group), and PFC (PF sedentary control group). The exercise protocol consisted of 60 minutes of moderate intensity aerobic exercise (50% of VO2) in a treadmill, five days a week, for 14 weeks. At the end of the study animals in TF and TFC groups were 44 weeks old, while PF and PFC mice were 30 weeks old. Weight (W) was registered weekly and caudal blood pressure (BP) was verified at the beginning and at the end of the study. Cross sections of aortic sinus were stained with oil-red O and lesion areas were quantified by an image analyzer.
Results: Initial BP and W were not different among the groups. Table 1⇓ shows BP and W at the end of the study. Atherosclerotic lesion areas were not different between exercised groups and their matched controls. However, PF group showed a marked decrease in plaque fat content as compared to its sedentary control (0.43±0.07 vs 0.56±0.02, p<0.05), suggesting that exercise turns atherosclerotic lesion to a more stable phenotype.
Conclusion: Preventive exercise decreased blood pressure in LDLr KO mice. Atherosclerotic plaque size was not modified by exercise, however, preventive exercise modified plaque morphology, decreasing its lipid content.