| Objective:To explore the new method of ChS (chondroitin sulfate) composited with CPC (calcium phosphate cement), and then to explore the porosity, setting time, biocompatibility, bone tissue reaction and intracorporal degradation.Methods:1.In vitro experiment:ChS granule and CPC were combined into 3 groups via different mixing ratio:C(control), C1 and C2 group(their CPC:ChS ratio are 10:0,9:1 and 8:2 respectively).Whether the holes formated was observed after calcined,while the porosity, initial and final setting time under 37 ℃ was measured.2. In vivo experiment:Cylindrical bone defects of 4.85mm diameter and 8mm deep were made in bilateral femoral epiphysis end on 18 femal New Zealand white rabbits, witch were averaged into two groups:CPC/ChS group and CPC/PLGA(Polylactic acid-glycolic acid copolymer). The bones were separately collected after 4,8 and 12 weeks, and Gross/ microscope observation were taken to analyze the biocompatibility,bone tissue reaction and intracorporal degradation of CPC/ChS composite.Result:1.In vitro experiment:Compared with C group, C1 and C2 group have more pores(10μm-50μm) under microscope after calcination. C1 and C2 group have higher porosity(P<0.05), initial and final setting time(P<0.01) contrast to C group. And the porosity, initial and final setting time of C,C1 and C2 group were separately (38.7±0.8)%, (52.7±1.2)%, (60.5±0.9)%, (4.04±0.37) min, (6.39±0.49) min, (12.54±0.92) min, (16.89±0.57) min, (36.90±1.49) min and (69.98±0.77) min.2.1n vivo experiment:Gross observing:New Zealand white rabbit recover smoothly after surgery, no swelling or purulency found on incision.Their living habits,feed and activity stay normal and no obvious change in body weight and no toxic or other abnormal reaction was observed.Histological examination:(1) CPC/ChS group:most of the ChS were dissolved and replaced by bone tissue,leaving the structure loose 4weeks after surgery.Perpheral CPC were replaced by bone tissue,the boarder was difficult to recognize and implant materials were incomplete 8 weeks after surgery. More the implant materials were dissolved remaining small part of CPC in the center and sporadic CPC granule in perimeter zone, and implant materials totally incomplete, normal loose organization occurred.(2) CPC/PLGA group:The basic fuchsin stain shows only a few of peripheral PLGA granule was dissolved,bone tissue grow along the surface of implanted materials which is compact 4 weeks after surgery. Irregular pores made by PLGA degradation were not found while bone tissue have covered the around the materials 8weeks after surgery. CPC have combined with new born bone tissue and only peripheral material dissolved.New bone tissue ratio:(1)CPC/ChS group:the new bone tissue ratio elevate gradually from 4weeks to 12weeks-12weeks(55.98±7.77)%>8 weeks (32.22±1.57)%>4 weeks (11.70±3.80)%; There are statistical significance among each of the group according analysis of variance (P<0.01). (2) CPC/PLGA group:new bone tissue area are separately (6.31±1.43)%in 4 weeks, (7.39±2.59)% in 8weeks and (8.20±1.71)% in 12 weeks. There are no statistical significance between any of the above group (P>0.05)Intergroup analysis:The new bone tissue ratio of CPC/ChS group were statistically higher(P<0.01) than that of CPC/PLGA group separately in 4weeks,8 weeks, or 12weeks.Conclusion:1.Composite of ChS and CPC can improve the porosity, but setting time is prolong.2.CPC/ChS composite has good bone repair ability and biocompatibility, which has a potential application possibility in bone tissue engineering field. |
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