Effect of exercise training on vascular reactivity in inbred strains of mice

Abstract

The aim of this study was to characterize the strain‐dependent differences in vascular reactivity in aorta from sedentary and exercise‐trained mice. Male mice (n ≈ 8/strain) from 5 inbred strains (129S1, 129X1, C57BL/6J, FVB, PWD) were assigned to either sedentary or exercise training (EX) groups. EX mice completed a 4‐wk treadmill running protocol (5 days/wk, 60 min/day, 60% of max speed). After training, aortic rings were suspended for isometric tension recording. Exercise training had no effect on vascular reactivity in any strain. Significant strain effects were found for maximal responses to phenylephrine (PE) and potassium chloride (KCl). For each agent, aorta from PWD had the lowest (PE = 5.4 ± 2.0 mN, KCl = 12.0 ± 2.6 mN) and aortas from 129‐substrains had the highest (PE = 16.4 ± 3.5 mN, KCl = 17.9 ± 3.3 mN) responses. Relaxation responses to acetylcholine were also different across strains, with aortas from the 129‐substrains having the lowest (73.0 ± 16.8%) and aorta from the FVB having the highest (90.6 ± 12.6%) responses. Relaxation responses to sodium nitroprusside were not different across strains. Strain‐dependent differences in sensitivity were observed for all agents tested. The large difference in maximal responses and sensitivity to vascular agents across mouse strains suggests that genetic background significantly affects vascular responsiveness.Supported by NIH grant HL085918 to MPM