Combining forced limb use with Ninjin’yoeito prevents atrophy in fast-twitch muscles and promotes functional restoration after hemorrhagic stroke in rats

Rehabilitative training with forced limb use (FLU) following intracerebral hemorrhage (ICH) enhances the functional recovery of skilled reaching in rats. To investigate whether the combination of FLU and Ninjin’yoeito (NYT) could yield superior functional recovery compared to FLU alone, rats were administered FLU from day 1 after ICH (D1) for seven days and 1% NYT chow until D56. This combination significantly enhanced the motor deficit score change at D28 and D56 compared to ICH alone, although it was comparable to that of FLU. This combination increased the total walking distance and entrance into the center area in the open-field test at D28. FluoroGold labeling of corticospinal neurons revealed no significant increase in the number of positive cells in the cortex of the combination group. Anterograde labeling demonstrated increased bouton-like varicosities in the red nucleus, similar to that observed with FLU, although NYT alone did not. Specific atrophy of MHC IIb-positive muscles after ICH was mitigated in the combination group, although no significant changes were observed in the FLU or NYT groups. The data indicate that the combined treatment with FLU and NYT after ICH facilitates the restoration of gross motor function and mitigates fast-twitch muscle atrophy on D28.