抄録
Purpose: Disuse of muscle results in atrophy and concurrent capillary regression. We have previously shown that exercise preconditioning prevented the disuse atrophy. Here we investigated whether and how exercise preconditioning affects capillary regression in disuse muscle atrophy by clarifying gene expression of angiogenetic factors. Methods: HIF-1α, VEGF, KDR/Flk-1, Flt-1, angiopoietin-1, and Tie-2, and several proteolytic systems were analysed using a real time polymerase chain reaction (PCR) in rat soleus muscle after hindlimb unloading for 2 weeks with and without exercise preconditioning. Results: The capillary density in unloaded soleus muscle with exercise preconditioning was significantly higher than that without exercise. Real time PCR analysis showed lower mRNAs expression levels of angiogenic factors in unloaded muscle without exercise preconditioning than that of control muscles. The exercise preconditioning attenuated the decreases in the expression levels of the angiogenic genes by muscle unloading, especially KDR/Flk-1, Flt-1 and Tie-2. Concluding Remarks: Disuse by hindlimb unloading induced significant reduction of the capillary network with decreases of angiogenic factors. Exercise preconditioning attenuated the capillary regression in hindlimb unloaded soleus muscle by preserving the gene expression levels of these angiogentic factors. [J Physiol Sci. 2007;57 Suppl:S243]
