Migration and homing of bone marrow mesenchymal stem cells in segmental nerve injury

Zhou Xue-feng; Ren Zhi-wu; Lu Ming; Wang Yu; Sun Zhen; Peng Jiang

doi:10.3969/j.issn.2095-4344.2015.28.008

Abstract：BACKGROUND:A large number of studies have confirmed that tissue-engineered stem cel therapy is feasible to repair peripheral nerve injury, but the repair mechanism is unclear. <br> OBJECTIVE:To observe the differentiation and homing of bone marrow mesechnymal stem cel s under local nerve microenvironment by exploring the migration and effect of bone marrow mesenchymal stem cel s in the repair of damaged nerve. <br> METHODS:Male SD rats, aged 8 weeks, were selected to establish segmental nerve injury models by freezing the sciatic nerve. Thirty-six model rats were randomized into three groups (n=12):frozen nerve injury group, cel injection into the nerve group, cel injection around the nerve group. Before modeling and at 4, 8, 12 weeks after cel implantation, the sciatic nerve function index was measured. Electrophysiological test, contractility recovery rate, wet weight recovery rate of the triceps surae were detected and Masson staining was performed;toluidine blue staining of the distal nerve injury and immunofluorescence staining of the damaged nerve were performed. <br> RESULTS AND CONCLUSION:At 4, 8, 12 weeks after cel implantation, the sciatic nerve function index was ranked as fol ows:frozen nerve injury group<cel injection around the nerve group<cel injection into the nerve group, but no significant difference was found among the three groups. Electrophysiological results showed that there was no difference in the latency and amplitude of compound muscle action potential between two cel therapy groups, but compared with the frozen nerve injury group, the latency was shorter and the amplitude was higher in the two cel therapy groups (P<0.05). Cross-sectional area of the muscle fibers was lower in the frozen nerve injury group compared with the other two groups. Immunofluorescence staining showed that Nestin, S100 and P0 proteins were al expressed in the two cel therapy groups 12 weeks after cel implantation. These findings indicate that bone marrow mesenchymal stem cel s added into the surrounding tissues of segmental damaged nerve can migrate into the damaged nerve, and even differentiate into Schwann cel s and neural stem cel s, which has a similar effect to the cel injection into the damaged cel s.