Transplantation of autologous bone marrow mesenchymal stem cells with platelet-rich plasma accelerate distraction osteogenesis in a canine model

Distraction osteogenesis [DO] is a surgical procedure used to generate large volumes of new bone for limb lengthening. In this animal experimental study, a 30% lengthening of the left tibia [mean distraction distance: 60.8 mm] was performed in ten adult male dogs by callus distraction after osteotomy and application of an Ilizarov fixator. Distraction was started on postoperative day seven with a distraction rate of 0.5 mm twice per day and carried out at a rate of 1.5 mm per day until the end of the study. Autologous bone marrow mesenchymal stem cells [BM-MSCs] and platelet-rich plasma [PRP] as the treatment group [n=5] or PRP alone [control group, n=5] were injected into the distracted callus at the middle and end of the distraction period. At the end of the consolidation period, the dogs were sacrificed after which computerized tomography [CT] and histomorphometric evaluations were performed. Radiographic evaluationsrevealed that the amount and quality of callus formations were significantly higher in the treatment group [P<0.05]. As measured by CT scan, the healing parametersin dogs of the treatment group were significantly greater [P<0.05]. New bone formation in the treatment group was significantly higher [P<0.05]. The present study showed that the transplantation of BM-MSCs positively affects early bony consolidation in DO. The use of MSCs might allow a shortened period of consolidation and therefore permit earlier device removal

[Conventional Vs. reverse nerve grafting for peripheral nerve repair in lower extremity of rats]

Autograft is the best option in nerve defects when end-to-end repair can not sufficiently preserve nerve continuity. Theoretically, if the severed nerve is reversely grafted, it may prevent axonal growth into nerve branches, and larger amounts of axons will reach the target organ and more satisfactory results will be obtained. In this study we aimed to compare conventional versus reverse nerve grafting. This study was performed in Animal laboratory of Hazrat Fatemeh Hospital from April till August 2011. We randomly divided 40 Wistar rats into two groups. We excised 1.5 cm of the right sciatic nerve and anastomosed it conventionally between the proximal and distal ends of the nerve in rats in group A and in a reverse manner in rats in group B. The rats' footprints were recorded in the first and 16[th] weeks after surgery. In week 16, the grafted nerves were removed under anesthesia for pathological examination and axon count. Subsequently, the results were compared clinically by sciatic functional index [SFI] through footprint analysis and paraclinically by axon count. A p-value smaller than 0.05 was considered statistically significant. Conventional and reverse nerve grafting no had statistically significant differences in clinical assessment in the first and 16[th] weeks [P=0.87] post-surgically and also no difference in paraclinical assessment in week 16 [P=0.68]. We had no significant clinically or para clinically differences between two approaches. It should be considered that the diameter and length of nerves and muscles in human is larger than rats, so the results of nerve repair may differ in human. We suggest a study in animal model which is anatomically more similar to human

[Comparing the effects of aspirin, clopidogrel and their combination on random skin flap survival in rats]

Random pattern flap is a common reconstructive surgery procedure but its necrosis is a challenging problem. A lot of pharmacological agents and surgical procedures have been examined for the prevention of this complication to maximize the length to width ratio of these surgical flaps. Therefore, we designed an experimental study to evaluate the effects of aspirin, clopidogrel bisulfate [Plavix] and their combination on random skin flap survival in rats. Forty male rats were randomly assigned to four equal groups. Surgery was done under general anesthesia. A random, rectangular 3x11 cm dorsal skin flap was designed, elevated and sutured back into its primary site. In group one, 100 mg/kg Aspirin and in group two, 25 mg/kg Plavix were administered orally for 7 days postoperatively. Aspirin and Plavix were co-administered in the third group for the same period of time while the control group received no medication. After 7 days, the total surface of flaps, the viable and also the necrotic parts were measured by Image J software. Mean standard deviation and analysis of variance were calculated to compare the results. The mean area of flap survival was 62.49% in the control, 64.04% in Aspirin, 65.09% in Plavix and 64.06% in combination groups. No statistically significant differences were found between treatment groups and control rats. In this study, we found no significant differences between Aspirin, Plavix or their combination on the survival of random skin flaps.