3D spheroid MDFs promotes the regeneration of the transected sciatic nerves. (A) Images of gross morphology, (B) H&E images, (C) Quantitative analysis of diameter (n = 6), and (D) TEM images of regenerated rat sciatic nerve 6 weeks following injury in different treatment groups. (E) Images of gross morphology of gastrocnemius muscle, (F) quantitative analysis of RGMW, and (G) H&E images in different treatment groups (n = 6). Data are mean ± SD. **P < .01. Abbreviations: HE, hematoxylin–eosin; TEM, transmission electron microscopy; Sham means rats without sciatic transection injury operation; Control means without MDFs transplantation.