ABSTRACT
BACKGROUND: Bone marrow mesenchymal stem cells have been extensively applied in animal experiments and clinical studies. The cell concentration, treatment times and results in each study are different, and there is no standard for optimal cell concentration. OBJECTIVE: To investigate the optimal concentration of bone mesenchymal stem cells injected into articular cavity in the treatment of rabbit cartilage defects. METHODS: Thirty 6-month-old New Zealand white rabbits were selected and randomly divided into control, 1×108, 1×109, 1×1010, and 1×1011/L groups. Cartilage defect models with diameter of 3 mm and depth of 2 mm were established in femoral trochlea in each group. One week after modeling, 1 mL of normal saline was injected into the rabbit’s knee of the control group. The other groups were injected with bone marrow mesenchymal stem cells at corresponding concentrations. After 6 and 12 weeks, gross observation, hematoxylin-eosin staining, Safranin-O-fast green-staining, type I and II collagen staining were performed to assess the cartilage regeneration. RESULTS AND CONCLUSION: In the control group, the defect area was obvious with no cartilage regeneration. The 1×108, 1×109, and 1×1010/L groups showed cartilage regeneration. The repairing effect was increased with the cell concentration increasing. The effect of cartilage repair in the 1×1011/L group was similar to that in the 1×1010/L group (P > 0.05). Therefore, 1×1010/L is the optimal concentration for intra-articular injection of bone marrow mesenchymal stem cells for treating cartilage defects, and higher concentration cannot enhance the repairing effect.
ABSTRACT
Objective To delay the atrophy of denervated skeletal muscle by baby-sitting in reverse end-to-side fashion and explore the feasibility of this operation to improve the recovery of denervated muscle in rats.Methods From July,2015 to March,2016,32 female SD rats were divided into 4 groups randomly and the tibial nerve of each rats was transected.In immediate repair group,the transected tibial nerve was sutured in situ.In unprotected group,the tibial nerve stump was putting-aside.The sural nerve was transected in other 2 groups.The proximal sural nerve was connected to the distal tibial nerve stump directly in end-to-end (ETE) protected group and to the side of the distal tibial nerve stump in end-to-side (ETS) protected group.After 3 months,connected the two ends of tibial nerve except immediate repair group.After another 3 months,the tibial nerve functional index,electrophysiological testing,histology and morphology were examined.Results The gastrocnemius muscle was atrophy obviously in unprotected group,while in other groups the muscle structure was well protected.The tibial nerve functional index (-39.54±24.32),motor nerve conduction velocity[(30.25±12.65)m/s],and muscle contraction [(0.98 ± 0.38)N)] indicated that the gastrocnemius muscle function in ETS protected group was statistically better recovery than in unprotected group [-75.65±32.13,(24.93±8.69)m/s and (0.64±0.20)N,respectively] and ETE protected group [-62.34± 21.65,(16.90±7.92)m/s and (0.75-±0.15)N,respectively](P＜0.05).The contractility of muscle were poor recovery in ETE protected group,which was similar to unprotected group(P＞0.05).Conclusion Sensory nerve baby-sitting in reverse end-to-side fashion is a effective method to improve the recovery of denervated muscle in rats.