Experimental research on different carriers applied with rabbits bone marrow mesenchymal stem cell transplantation combined with hyperbaric oxygen in the treatment of the open rabbits radial bone defect associated with seawater immersion

Abstract

Objective To investigate the osteogenic effect of different carriers applied with rabbit bone marrow mesenchymal stem cell (BMSC) transplantation combined with HBO in the treatment of open rabbit radial bone defect associated with seawater immersion. Methods Forty-eight New Zealand white rabbits were randomly divided into 4 groups: Group A (the simple BMSC transplantation + HBO group), Group B (BMSC transplantation + Autologous bone + HBO group), Group C (the BMSC transplantation + PLGA + HBO group), and Group D (the BMSC transplantation + gelatin sponge + HBO group), each consisting of 12 animals. Bilateral bone defects with a length of 15mm were made in the middle of the radial bone, and then debridement was made 3 hours after immersion in the artificial seawater. Bone tissue transplantation was performed right after debridement, and HBO therapy was implemented 1 hour a day for a succession of 2 weeks. The animals were sacrificed 8 and 12 weeks after surgery in batches of 4 in each group, and a total of 8 radial bones were collected. The repair of bone defects in each group of animals was compared between the 4 groups, through detection by X-ray, bone callus grey value, HE staining, and biomechanical testing. Results (1) X-ray detection indicated that osteogenic efficacy of the 4 groups was group B > group C > group D > group A. (2) As shown in Figure 1, 12 weeks after injury, bone callus grey values for the 4 groups were respectively as follows: group A: 162.1±1.3; group B: 220.1±1.2; group C: 195.6±1.7 and group D: 185.3±1.6. Statistical significance could be noted, when comparisons were made between the groups(P<0.05). (3) HE staining indicated that residual material could be seen in group C and D, 4 weeks after injury. Bone repair could all be seen in the bone defect areas, with the bone repair of group B being the best, and the bone repair of group C was superior to that of group D, and the bone repair of group D was superior to that of group A. Twelve weeks after injury, the repair materials in groups C and D were all degraded. The quality of the repaired bones was best in group B, which was followed by groups C, D and A. and statistical significance could be noted, when comparisons were made between the groups(P<0.05). (4) Twelve weeks after injury, biomechanical testing indicated that significant differences could be noticed in load capacity of the radial bone in the 4 groups. The load capacity of group B was the best, which was respectively followed by groups C, D and A (P<0.05). Conclusions (1) Autologous bone, PLGA and gelatin sponge as carriers combined with BMSC and HBO could all repair bone defect, and the advantage of combined treatment was obviously superior to that of BMSC bone transplantation alone. The quality of the repaired bones in the autologous bone group was the best, and the effect of PLGA as the carrier was better than that of the gelatin sponge as the carrier. (2) In the treatment of bone defects, particularly in the treatment of large section bone defect, PLGA in replacement of autogenous bone was a practical and effective treatment method, when autologous bone was insufficient or not available. Key words: Seawater immersion; Open bone defect; Bone marrow mesenchymal stem cell; Hyperbaric oxygen; Carriers; Rabbits