Adenovirus vector-mediated ex vivo gene transfer of brain-derived neurotrophic factor (BDNF) tohuman umbilical cord blood-derived mesenchymal stem cells (UCS-MSCs) promotescrush-injured rat sciatic nerve regeneration

This study was designed toinvestigate the efficacy of adenovirus vector -mediated brain -derived neurotrophic factor (BDNF) ex vivo gene transfer to human umbilical cord blood -derived mesenchymal stem cells (UCB-MSCs) in a rat sciatic nerve crush injury model. BDNF protein and mRNA expression after infection was checked through an enzyme -linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR). Male Sprague-Dawley rats (200-250g, 6 weeks old) were distributed into threegroups (n=20 each): the control group, UCB-MSC group, and BDNF-adenovirus infected UCB-MSC (BDNF-Ad+UCB-MSC) group. UCB-MSCs (1 x 10(6) cells/10 mu l/rat) or BDNF-Ad+UCB-MSCs (1 x 10(6) cells/10 mu l/rat)were transplantedinto the rats at the crush site immediately after sciatic nerve injury. Cell tracking was done with PKH26-labeled UCB-MSCs and BDNF-Ad + UCB-MSCs (1 x 10(6) cells/10 mu l/rat). The rats were monitored for 4 weeks post surgery. Results showed that expression of BDNF at both the protein and mRNA levels was higher inthe BDNF-Ad + UCB-MSC group compared to theUCB-MSC group in vitro.Moreover, BDNF mRNA expression was higher in both UCB-MSC group and BDNF-Ad+ UCB-MSC group compared tothe control group, and BDNF mRNA expression in theBDNF-Ad + UCB-MSC group was higher than inboth other groups 5 days after surgeryin vivo. Labeled neurons in tile dorsal root ganglia (DRG), axon counts, axon density, and sciatic function index were significantly increased in the UCB-MSC and BDNF-Ad+ UCB-MSCgroupscompared to the controlgroup four weeksaftercell transplantation. Importantly,the BDNF-Ad + UCB-MSCgroup exhibited more peripheral nerve regeneration than the other two groups.Our results indicate thatboth UCB-MSCs and BDNF-Ad + UCB-MSCscan improve rat sciatic nerve regeneration, with BDNF-Ad + UCBMSCsshowing a greater effectthan UCB-MSCs. (C) 2017 Elsevier B.V. All rights reserved.