Abstract
[Purpose] We investigated the influence of differences in the duration of hindlimb suspension (HS) on myofiber hypertrophy. [Subjects] Twenty-eight male Wistar rats were used. [Method] Rats were randomly assigned to groups for 7 days of HS (H7), or HS and 1 day of reloading (W1), 3 days of reloading (W3), or 7 days of reloading (W7). The results were compared with the control, and 14 days of HS and reloading groups (C, H14, R1, R3, R7) of our previous study using the same conditions. [Result] Myonuclear numbers were significantly decreased in the H14 group compared with the C group. Myofiber necrosis was significantly increased in the H14 group compared with the C group. Myofiber cross-sectional area was significantly increased in both the W1 (9%) and R1 groups (5%) compared with the H7 and H14 groups, respectively. [Conclusion] The results suggest that the earlier myofiber was reloaded, the greater the myofiber hypertrophy.
