| Objective To observe the osteogenic effect of recombinant human growth hormone(rh GH)combined with melatonin(MT)on the repair of rabbit tibia defect,and to identify the combination role of two drugs in the repair of bone defect.Methods Take 24 male New Zealand white rabbits(4 ~ 6 months,2.5 ~ 3.0 kg)random label,in the bilateral tibial preparation of 5 mm in diameter,depth of 6 mm bone defect model,1-12 # rh GH-MT combination group,left for the local implanted with 1 iu rh GH in tibia defect and 0.3 mg of MT 0.1 ml of autologous blood clots,12# 1-on the right side as the blank control group,local implanted in tibia defect 0.1 ml of autologous blood clots;The left side of 13-24# was the MT group,and 0.1ml autologous blood clot containing only 0.3mg MT was locally implanted at the tibial defect.The right side of 13-24# was the rh GH group,and 0.1ml autologous blood clot containing only 1IU rh GH was locally implanted at the tibial defect.Gross observation,X-ray imaging,histological observation and bone histomorphological measurement were performed at 1,2 and 4 weeks after surgery.Results Gross observation,X-ray imaging and histological observation showed that each group had different degrees of new bone tissue formation: at the first week after surgery,the intraoperative defect of rhgh-mt group was smaller than that of the other three groups,with fewer inflammatory cells and more fibrous connective tissue.Granulation tissue,inflammatory cells and fibrous connective tissue were randomly distributed in rh GH group and MT group.At the second week after surgery,the rhgh-mt group presented a small depression with a high density of photography,and a large number of fibrous connective tissue,bone trabeculae and active osteoblasts were observed.The defects in the rh GH group and MT group were smaller than those in the blank group,and the X-ray images were similar.At the fourth week after surgery,a large amount of new bone was found in the defect area of the rhgh-mt group,with a relatively tough texture and difficulty in penetrating with probes.There was a relatively flat cortical bridge,and the boundary between bone and old bone was clear.In the rh GH group and MT group,there were fewer newborn bone in the central surgical area than the combined group,with probe penetration,low density shadow at the defect edge,continuous trabecular bone distribution but fewer osteoblasts than the composite group.At the first,second and fourth weeks after the operation,the percentage of the osteogenic tissue area of the rh GH--MT group was 39.02% 2.16%,44.68% 1.83%,55.10% 2.98%,and the percentage of the osteogenic tissue area of the rh GH group was 32.08% 1.39%,36.78% 1.91%,45.45% 2.75%,respectively.The percentage of the osteogenic tissue area of the MT group was 32.16% 1.27%,36.96%2.35%,46.63% 2.43%,respectively.The percentage of new osteogenic tissue area was28.05% 1.26%,30.25% 2.23%,36.40% 1.68%,respectively.In the rh GH--MT group,the ratio of newly generated bone tissue area at the first,second and fourth weeks after surgery was greater than that of the other three groups(P<0.05).In longitudinal comparison,except the blank group,there were statistically significant differences in the percentage of new osteogenic tissue area between the three groups at week 1,2and 4(P<0.05).Conclusion Topical application of recombinant human growth hormone combined with melatonin can effectively promote the formation of new bone tissue in the bone defect area,and the effect is better than using two materials separately. |
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