Fig. 9

Histological evaluation of the gastrocnemius. a Representative results of the gastrocnemius on the injured side shows visible atrophy in the Hollow group and 2D group compared with the normal side at the 12th week after transplantation. In contrast, the other two groups were less pronounced (up row). Masson staining of the gastrocnemius muscle in the four groups showed the hyperplasia of blue-stained collagenous between the red-stained muscle fibers (bottom row). Scale bars: 1 cm (up row) and 50 μm (bottom row). b The gastrocnemius wet weight recovery ratio in the Microtissue group was significantly higher than the 2D group (p < 0.05), and there was no statistical difference between the Microtissue group and ANG group. c The mean cross-sectional area of gastrocnemius fibers in the Microtissue group was significantly greater than the 2D group (p < 0.01), and there was no statistical difference between the Microtissue group and ANG group