Marrow stromal stem cell autologous transplantation in denervated fracture healing: an experimental study in rats.

Objective: To investigate the influence of bone marrow stromal stem cell (BMSCs) transplantation on healing of fractures combined with central nerve injuries in rats. Methods: Forty-eight healthy adult SD male rats were randomly divided into the following three groups (16 rats in each group): group A, simple (left) tibial fracture; group B, tibial fracture combined with T-10 spinal cord transection (SCT); group C, tibial fracture combined with T-10 SCT and BMSCs transplantation. The tibial fractures were stabilized with modular intramedullary nails and all operated hind limbs were further immobilized in plaster casts to prevent unequal load bearing. BMSCs were labeled with bromodeoxyuridine and implanted into the fractures of C group rats 2 days after creation of the model. The animals in B and C groups were evaluated by postoperative Tarlov scores. The fractured tibiae were evaluated separately radiographically (X-ray and CT) and immunohistochemically 1, 2, 3 and 4 weeks after injury to assess fracture healing. In addition, the wet weights of the left tibias were measured. Results: All Tarlov score of the B and C group animals reached the requirements of the experiment. One, 2 and 3 weeks after surgery, the tibial callus widths in B and C group animals were significantly greater than those of group A rats (P < 0.05). At 4 weeks the tibial callus width in group C animals had decreased, but still differed significantly from that in group A rats (P < 0.05). One, 2, 3 and 4 weeks after surgery, the wet weights of B and C group tibias were significantly greater than those of group A (P < 0.05). Hematoxylin-eosin-stained sections showed bony union and increased bone trabecula in B and C groups and areas with particles positive for alkaline phosphatase staining were more abundant in groups B and C, especially in group C. Conclusion: Neural regulation plays an important role in fracture healing. Treatment with BMSCs has a positive effect on defective callus in rats that have been subjected to SCT.