| BackgroundThe anatomic structure of pelvis and acetabulum is complex.It is a new technique to treat the complex acetabular fracture involving tetrahedral body with metal 3D printed individualized titanium alloy plate.However,the biocompatibility of that plate is unknown.At present,the relevant domestic research in this area is in its infancy.ObjectivesIt is the personalized designed acetabular bone plate for patients with complex acetabular fractures involved tetrahedral body.Then,using metal 3D printing technology to produce the plate,and investigating the biocompatibility of the plate by in vitro and in vivo experiments.To provide the safety and ethical basis for the clinical application of that plate.MethodsIn vitro experiments Metal 3D printing plate leaching solution was prepared by DMEM as extraction medium based on international standard ISO 10993-12.In the cytotoxicity test,the cells were co-cultured with different concentrations of extractant and control group.Cell growth and morphological changes were observed under microscope.OD values were measured by CCK-8 method and RGR was calculated to evaluate the effect of the plate on cell activity and proliferation.In vivo experiments C57 mice were injected with the extractant of the plate through tail vein.The acute systemic toxicity of the plate was evaluated by comparing it with the control group:the life state of the mice after injection and the changes of body weight for 3 consecutive days.Albino guinea pigs were randomly divided into three groups:experimental group,blank control group and positive control group.Skin sensitization test was carried out in the back and abdomen of guinea pigs.The sensitization of the plate was evaluated by gross observation and pathological section of skin.New Zealand white rabbits were randomly divided into two groups:the experimental group and the control group.The metal 3D printed titanium alloy plate and the titanium alloy plate commonly used in clinic were implanted into the back muscle of the white rabbit by surgical operation.The animals were killed through air embolism at 1 week,4 weeks and 12 weeks,respectively.The histocompatibility of the titanium alloy plate was evaluated by observing the inflammatory reaction around the plate and the pathological changes of liver and kidney by pathological sections and H-E staining.ResultsIn vitro experiments In 3 time nodes on cell growth was observed under the microscope in good condition,no morphological changes,there were no obvious apoptosis and necrosis.The OD value of each group increased gradually with the increase of culture time by CCK-8,the difference was significant(p<0.05),and the range of RGR in test group was from 72.65%to 106.58%.In vivo experiments There was no significant difference in life status between C57 mice and control group,at the same time there was no significant difference in weight change between C57 mice and control group(P>0.05).In the sensitizing test,the skin changes in the back and abdomen of the experimental group and the blank control group were similar.There was no redness,rupture,mild inflammatory reaction and a small amount of inflammatory cell aggregation in pathological sections.In the implantation test,there was no obvious infection in the surgical incision of the experimental animal,and the wound healed.The specimens were taken for pathological section and staining at 3 time points respectively.In the experimental group,there were no obvious inflammatory cell infiltration and degenerative necrosis in the muscle tissue around the bone plate,and no obvious signs of heavy metal ion destruction in liver and kidney,which were similar to those in the control group.ConclusionIn this study,the biocompatibility of metal 3D printed titanium alloy plate was studied from many aspects and angles,and the good biocompatibility was verified,which provided the safety guarantee and ethical basis for its clinical application. |
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