[Initial immunoreaction study on PVA/n-HA + PA66 biological composite material after being implanted into animal body].

OBJECTIVE: To observe immunoreaction to PVA/n-HA+ PA66 biological composite material after being implanted into animal body. METHODS: PVA/n-HA+PA66 composite materials were implanted into mouse subcutaneous tissue. Histologial examination was performed at 2, 4, 6 weeks, the amount of CD3, CD4+, CD8+ in blood and IL-1, IL-6, TNF-alpha in spleen cells was measured at the same time. RESULTS: The amount of CD3, CD4+, CD8+ in mouse blood and IL-1, IL-6, TNF-alpha in mouse spleen cells were not different with the control groups at 2, 4, 6 weeks (P > 0.05). The fibrous tissue and some blood vessels were found growing into the porous materials, which resulted in composite materials intergration of proliferative structure. The reject reaction was not found. CONCLUSION: PVA/n-HA+PA66 biological composite material does not cause immune rejection after being implanted into animal body, verifying its good biocompatibility.

[Porous polyvinyl alcohol hydrogel composite prepared and studied initially for biocompatibility].

OBJECTIVE: To investigate the feasibility of porous polyvinyl alcohol hydrogel (PVA-H) composite, for tissue engineering scaffold. METHODS: The approach of emulsifier-foaming, freeze-drying and surfactant-cleaning method was developed to gain three kinds of porous scaffolds: porous polyvinyl alcohol (PVA), porous polyvinyl alcohol/nano-hydroxyapatite (PVA/n-HA) and porous polyvinyl alcohol/chitosan (PVA/Cs). We checked the physical features of the above three kinds of materials and further investigated their biocompatibility by SEM image analysis, mechanics test, MTT and muscle implanting. RESULTS: Three kinds of materials had the similar character of high porosity (80%), but the PVA/n-HA had the smallest mean pore size (154.5 microm) and the PVA had the biggest tensile strength (0.60 Mpa). MTT assay demonstrated three kinds of materials to have no toxicity, furthermore, PVA had better absorbance, compared with cell control group (P < 0.05). After muscle implantation, there were many muscular tissues growing into pores of PVA/Cs at the 4th week, although PVA/Cs had stronger inflammatory reaction. Other two kinds of materials had very small inflammatory reaction and there were many fibrous tissues growing into pores at the 1st, 4th, 12th week. CONCLUSION: The features of materials are changed after adding n-HA or Cs, moreover, porous PVA/Cs seems to have the activity of inducing muscle growth. Porous PVA and its composites may be applied to tissue engineering as a long-term or permanent scaffold due to their good biocompatibility, elasticity and hydrophilicity.

[Current treatment situation and progress on bone defect of collapsed tibial plateau fractures].

Characteristics of collapsed tibial plateau fracture determines that the joint surface must remain anatomical reduction,line of force in tibial must exist and internal fixation must be strong. However, while renewing articular surface smoothness, surgeons have a lot of problems in dealing with bone defect under the joint surface. Current materials used for bone defect treatment include three categories: autologous bone, allograft bone and bone substitutes. Some scholars think that autologous bone grafts have a number of drawbacks, such as increasing trauma, prolonged operation time, the limited source, bone area bleeding,continuous pain, local infection and anesthesia,but most scholars believe that the autologous cancellous bone graft is still the golden standard. Allograft bone has the ability of bone conduction, but the existence of immune responses, the possibility of a virus infection, and the limited source of the allograft cannot meet the clinical demands. Likewise, bone substitutes have the problem that osteogenesis does not match with degradation in rates. Clinical doctors can meet the demand of the patient's bone graft according to patient's own situation and economic conditions.