Study Of Bone Marrow Mesenchymal Stem Cells Combined With NHAC In Repair Of Tibial Defects In Rabbits

Bone defect on clinically is very common.The therapy of bone defect is one of the tough problem in department of orthopaedics.The commonly used ways of the therapy are autogenous bone transplantation, variant bone transplantation and artificial bone transplantation.They are all have disadvantages which are hard to overcome.Tissue-engineering utilizes the philosophy and technique of life science and engineering.It is through scheming,constructing,cultivating and conserving living cells to study and research organismal surrogate,to recover and rebuild the constitution of human tissue and organ,to maintain or improve the functions of tissue and organ.It is a newly emerging subject and also is a investigative hot spot at present.Objective:This paper is to explore the feasibility of rabbit bone marrow-derived mesenchymal stem cells(MSCs)and nano-hydroxyapatite/collagen(NHAC)in constructing tissue-engineering bone recombinated in vitro,as well as the feasibility of recovering the rabbit tibia bone defection by the tissue-engineering bone.Methods:Rabbit MSCs were isolated and purified in vitro,and the rabbit MSCs of 3rd-generation were seeded onto prepared nano-hydroxyapatite/collagen(NHAC).Their adhesion situation was analyzed by scanning electron microscope(SEM)after 5,10 days.Then 20 healthy adult New Zealand rabbits are made into the model of 10mm bone defects in the middle of the tibias.Rabbits with tissue-engineering bone planted on the right side as the experimental group and NHAC planted on the left side as the control group.Animals are executed in batch postoperative 3,6,9,12 weeks.General conditions,macroscopic evaluation,X-ray,the bone density measurement and histomorphology examination of bone defect repairing sample and statistical analysis were performed in order to compare the effects of repairing bone defects of the two groups.Results:1.Rabbit bone marrow-derived mesenchymal stem cells(MSCs)grow adherent.The speed of generation is fast.The growth curve is fit for Logistic growth curve.2.Rabbit bone marrow-derived mesenchymal stem cells(MSCs)and nano-hydroxyapatite/collagen(NHAC)are cultivated in vitro,the scanning electron microscope is used to observe at 5^th,10^thday.It can be seen that MSCs cell population adhered onto NHAC at 10^thday (38.52±7.21)are obviously more than at 5^thday(21.28±4.70),P＜0.01.3.All the general state of health of New Zealand rabbits are fine.The postoperative recovery and foodintake are normal.There is no inflammation present in the wound.The concrescence is fine.4.Macroscopic evaluation:the bone defection of the experimental group were completely repaired at postoperative 12 weeks.The prothetic condition of bone defection are obviously better than the control group. The latter are partly recovered.5.X-ray examination:in the experimental group,the formation of scars can be seen at postoperative 3 weeks,and the bone defects were generally repaired at postoperative 9 weeks.In the control group,the bone defects were generally repaired at postoperative 12 weeks.The repair of bone defects of experimental group were better than it of control group at each of the observing times.6.The bone density measurement:the bone density of experimental group postoperative 3 weeks,6 weeks,9 weeks,12 weeks are 0.789±0.082,1.205±0.137,1.550±0.120,1.609±0.299 respectively.They are high than the bone density of control group.The latter are 0.475±0.039,0.921±0.136,1.131±0.153,1.192±0.236 respectively.All P＜0.05.7.Histomorphology:In the experimental group,the amount of osteoid tissue was larger than it in the control group,and in the defect more mature osteocytes and discus bone can be seen.In the control group, mature osteocytes and new woven bone can be seen,few hyperaemia and necrotic tissue in some samples. Conclusion:According to the experimental results,we can make the conclusion: the conjunctive extent of the rabbit bone marrow-derived mesenchymal stem cells(MSCs)and nano-hydroxyapatite/collagen(NHAC)cultivated together in vitro is high.According to it,we can construct tissue-engineering bone.The bone defect repair ability of tissue-engineering bone which constructed with allogenic bone marrow mensenchymal stem cells and nano-hydroxyapatite/collagen(NHAC)is strong compared with NHAC alone.So the tissue-engineering bone could repair the long bone defects rapidly and effectively.