Pharmacological inhibition of Rac1 attenuates myocardial abnormalities in tail-suspended mice

Microgravity conditions cause myocardial abnormalities with limited therapeutic approaches. We reported that NADPH oxidase-derived reactive oxygen species contribute to microgravity-induced myocardial abnormalities. This study investigated whether pharmacological inhibition of Rac1 protected the heart during microgravity. Simulated microgravity was induced by tail-suspension in mice. Tail-suspension for 28 days increased Rac1 activity in hearts, reduced heart weight and cross-sectional areas of cardiomyocytes, indicative of myocardial atrophy, and myocardial dysfunction. Administration of NSC23766, a selective inhibitor of Rac1, or atorvastatin reported to inhibit Rac1 activation, attenuated myocardial atrophy and preserved myocardial function in tail-suspended mice. These protective effects of Rac1 inhibition were associated with inhibition of NADPH oxidase activation and a reduction of oxidative stress. Our finding may inform a future clinical trial using atorvastatin to prevent myocardial abnormalities under microgravity conditions.

Automated summary

Microgravity-induced myocardial abnormalities can be prevented and treated by inhibiting Rac1, which is associated with the inhibition of NADPH oxidase activation and reduction of oxidative stress. This finding may pave the way for future clinical trials using atorvastatin to prevent myocardial abnormalities under microgravity conditions.