Effects Of Combined Low-intensity Resistance Training And Chlorella Intake On Endothelial Function In Aged Mice

Aging causes vascular endothelial dysfunction, resulting in the progression of cardiovascular diseases. Several studies showed that low-intensity resistance training may elevate vascular endothelial function. Chlorella, which contains various nutrients, is a type of single-celled green algae. Recent our study showed chronic chlorella intake improved vascular endothelial function in aged mice. However, it is unclear whether chronic chlorella intake combined with low-intensity resistance training further improves vascular endothelial function. PURPOSE: This study aimed to clarify the combined effects of low-intensity resistance training and chlorella intake on vascular endothelial function in aged mice. METHODS: In this study, 38-week-old male senescence-accelerated mouse prone 1 (SAMP1) mice were divided into sedentary control (Con, N = 7), chlorella intake (CH; 0.5% chlorella powder in normal diet, N = 7), low-intensity resistance training (LRT, N = 8), LRT and CH combined (LRT + CH, N = 8) groups. Low-intensity resistance training was performed 3 days a week for 12 weeks using a climbing ladder with 40% of 1 repetition maximum (1RM) weight. Mouse aortic rings were isolated for the evaluation of vasorelaxation responses to acetylcholine (ACh, endothelium-dependent) and sodium nitroprusside (SNP, endothelium-independent) using a wire myograph. RESULTS: The ratio of 1RM to body weight in LRT + CH group was significantly higher than that in the Con and CH groups (each p < 0.05). Endothelium-dependent vasorelaxation of the isolated mouse aortic rings with adding ACh in the LRT, CH, and LRT + CH groups were significantly higher compared to that in the Con group. Additionally, the endothelium-dependent vasorelaxation response in the LRT + CH group was significantly higher than that in the LRT or CH groups (each p < 0.05). However, no significant differences in endothelium-independent vasorelaxation of the mouse aortic rings with adding SNP were observed among the four groups. CONCLUSION: These findings suggest that the chlorella intake combined with low-intensity resistance training may further improve vascular endothelial function along with muscle strength in aged mice. Supported by Grants-in-Aid for Scientific Research (#22H03487, M. Iemitsu) and Sun Chlorella Corp.