| Objective:After complete debridement of chronic osteomyelitis and autogenous granular cancellous bone grafting,use low-frequency pulsed electromagnetic field and multispectral therapeutic apparatus to explore whether it can promote revascularization of the bone graft,thereby improving the anti-infection ability of the bone graft area.Speed up bone healing.Methods:1.Establish rabbit tibia osteomyelitis model and related diagnosisNew Zealand white rabbits were selected to establish a rabbit left tibia chronic osteomyelitis model.One month later,the model rabbits were examined by blood cell examination,imaging,histopathology,visual observation,and bacterial culture at the infected lesion to determine whether the model was successful.2.Grouping and debridement bone grafting treatment72 New Zealand white rabbits with successful modeling were selected and divided into four groups using a random number table: blank group(group A),control group(group B),multi-spectral treatment group(group C),and low-frequency pulsed electromagnetic field group(group D),18 per group.All four groups were thoroughly debrided.Group A complete debridement without bone grafting,Group B complete debridement of phase I granular cancellous bone grafting,Group C complete debridement of phase I granular cancellous bone grafting for multispectral treatment,and Group D complete debridement of phase I Granular cancellous bone graft for low frequency pulse electromagnetic field treatment.Postoperative antibiotics were routinely used and fed in a single cage.3.Detection and evaluation of anti-infective ability after debridementOn the 3rd,7th and 14 th day after operation,blood was collected from the ear veins of the four groups of experimental rabbits,and the changes of WBC,CRP and PCT were detected and analyzed statistically.4.Detection and evaluation of bone formation and revascularization abilityOn the 7th day after surgery,the four groups of bone tissue samples were selected for HE staining,and the number of new blood vessels was counted and analyzed statistically.Bone tissue specimens were selected from the four groups on the 3rd,5th,7th,14 th,and 21 st days after operation,and the expressions of VEGF and BMP-2 were quantitatively detected by Western blotting.At 1 and 12 weeks after operation,the experimental rabbits of each group were taken for CT scan to observe the bone repair and regeneration.Results:1.Modeling results: 4 weeks after modelling,gross observation: abscess and ulcer formation;X-ray suggestion: destruction of worm-like bone,CT suggestion: formation of pus cavity and small dead bone,soft tissue swelling.Blood test routine: white blood cell count(14.23±2.78)109/L;CRP:(8.07±1.24)mg/L;PCT:(5.26±2.58)ng/ml.General bacterial culture: serum enzymes are diagnosed as S.aureus infection;histopathological examination: a large number of inflammatory cell infiltrations can be seen under the microscope.Modeling success rate: 4 accidental deaths due to anesthesia,5 deaths due to severe infection or bacteremia,2 undiagnosed chronic osteomyelitis,the success rate of rabbit chronic osteomyelitis model modeling is 86.7%,and another batch of experimental rabbits will be made later The model complements the experimental data.2.Anti-infection index test results:WBC results: There was no statistically significant difference between the four groups on the third day after debridement(P>0.05);the difference between the groups C and D and the groups A and B on the seventh day after debridement was significant.Statistical significance(P<0.05);the difference between group C and group D and group A and group B on the 14 th day after debridement was statistically significant(P<0.05).CRP results: There was a statistically significant difference between group C and group D and group A and group B on the 3rd day after debridement(P<0.05);group Cand group D and group A and group B on the 7th day after debridement The difference between the two comparisons was statistically significant(P<0.05);the difference between the groups C and D and the groups A and B on the 14 th day after debridement was statistically significant(P<0.05).PCT results: There was a statistically significant difference between group C and group D and group A and group B on the 3rd day after debridement(P<0.05);Group C and group D and group A and group B on the 7th day after debridement The difference between the two comparisons was statistically significant(P<0.05);the difference between the groups C and D and the groups A and B on the 14 th day after debridement was statistically significant(P<0.05).3.Pathological examination results: On the 7th day after debridement,four groups of bone tissue samples were randomly selected for HE staining.A large number of inflammatory cell infiltrations were seen under the pathological section microscope in group A,and new capillaries scattered in the middle;group B pathological section microscope A large number of inflammatory cell infiltrations can be seen below,and osteoblast proliferation can be seen,and a small number of small blood vessels have grown in;group C pathological sections show that the degree of inflammatory cell infiltration is reduced compared with groups A and B,and more chondrocytes mature and new bone trabeculae There is a small amount of inflammatory cell infiltration in the pathological section of group D,more chondrocytes are mature,microvessel growth is increased,and new trabecular bones are visible.Count of capillary neovascularization under microscope: the difference between group C and D and group A and B was statistically significant(P<0.05).4.Western blot detection results:VEGF expression results: 3,5,7,14 days after debridement,the expression of VEGF in groups C and D Both were higher than Group A and Group B,the difference was statistically significant(P<0.05).The expression of VEGF in the two groups C and D reached the peak on the 7th day.BMP-2 expression results: On the 3rd,5th,7th and 14 th days after debridement,the expression of BMP-2 in group C and group D were higher than those in group A and group B,the difference was statistically significant(P<0.05).Among the two groups C and D,the expression level of BMP-2 reached its peak on the 14 th day.On the 21 st day after debridement,the difference in BMP-2 expression between the four groups was not statistically significant(P>0.05).5.CT scan results:Group A 1 week after operation: bone defect is obvious,no granular bone implantation;12 weeks after operation: poor bone healing;Group B: 1 week after operation: bone graft particles can be seen at the bone defect;12 weeks after operation: some bone graft particles are absorbed,the bone cortex is continuous at the original bone defect,and the new bone cortex is weaker than the normal bone cortex;Group C: 1 week after operation: bone graft particles can be seen at the bone defect;12 weeks after operation: most of the bone graft particles are absorbed,and the bone cortex is continuous at the original bone defect;Group D 1 week after operation: bone grafting particles were visible at the bone defect;12 weeks after operation: bone grafting particles were completely absorbed and the bone cortex was continuous at the original bone defect.Conclusion:1.After complete debridement of chronic tibia osteomyelitis in rabbits,autogenous granular cancellous bone grafting,treatment with low-frequency pulsed electromagnetic field and multi-spectral therapeutic apparatus can reduce the inflammation of the tissue surrounding the bone graft and increase the tissue’s ability to resist infection.2.The low-frequency pulsed electromagnetic field and multi-spectral therapeutic apparatus can up-regulate the expression of VEGF and BMP-2 in the bone grafting area,therebyPromote the vascularization and osteogenesis of the bone grafting area,and accelerate the speed of bone healing. |
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