Research Paper Volume 16, Issue 5 pp 4609—4630

Figure 5. MPC-EXO and MPC-Exo¹⁴⁰⁻ advanced the repair of gastrocnemius muscle after acute injury. Eight-week-old male wildtype C57BL/6 mice were treated with MPC-Exo, MPC-Exo¹⁴⁰⁺ and MPC-Exo¹⁴⁰⁻ 3 times after acute injury. (A) presents a schematic diagram of muscle injury modeling treated with MPC-EVs. (B–G) depict the HE staining results after three treatment sessions, with arrows pointing to central nuclei. The control group (B) shows closely arranged muscle cells with nuclei at the cell periphery. The injury group (C) presents newly formed muscle cells with centrally located nuclei and a few inflammatory cells between cells. In the MPC-Exo intervention group (D), the nuclei of newly formed muscle cells migrated toward the cell membrane. The MPC-Exo¹⁴⁰⁺ intervention group (E) shows numerous centrally located nuclei in newly formed muscle cells and a loose extracellular matrix structure. In the MPC-Exo¹⁴⁰⁻ intervention group (F), the muscle cells were closely arranged, and the nuclei of newly formed muscle cells moved to the cell periphery. The AAV-KO-140 injury group (G) shows newly formed muscle cells with nuclei relocated to the cell periphery, but the fusion process between cells and newly formed multinucleated myotubes is inhibited, resulting in a significant increase in the number of nuclei (Scale bar in 100 μm).