| ObjectiveTo investigate the method and preliminary effects of high energy extracorporeal shock wave to intervene the osteonecrosis femoral head of the rabbits, so as to simulate minimally invasive pathogenic factors in ONFH.Materials and Methods30 New Zealand white rabbits as SPF level, aged 2.5 to 3 months, were randomly averaged divided into three groups. The rabbits in A, B, C group were treated with steroid combined with lipopolysaccharide, steroid combined with ESW, steroid combined with lipopolysaccharide and ESW as intervention measures, respectively.Among them, the ESW were implemented with the target of left femoral head and the energy of 14 W, 1000 times after 48 h, only 1 times. Prednisolone acetate(20mg/kg)were intramuscular injected 3 times in the gluteal muscle, respectively in the 24 h, 72 h,96h. lipopolysaccharide(2.0g/kg)were ear vein injected in the 48 h, same as the time of ESW intervention. Intramuscular or intraperitoneal injection of penicillin sodium(5mg/kg),amikacin(1.63 × 104U/kg)were given once every 24 hours for 14 days. The rabbits survival score were observed continuously. The femoral head MRI scanning were underwent in the 4th day and the third weeks before and after., Other examinations,such as blood coagulation function test, MRCP, CTA examination, bone analysis, and HE staining of the femoral head were operated at the end of the experiment when the rabbits were executed according to our plan. Compared with the 4th day MRI image,and summarized all the dates as rabbits living conditions, coagulation function, local blood supply and the bone micro structures, etc. With the results of HE staining and pathological examination as the gold standard, the effect of high energy ESW intervention on the course of ONFH in rabbits were analyzed, and the advantages and disadvantages of the experimental methods were also analyzed.ResultsDuring the experiment, there were 2, 3, and 2 rabbits died in A, B, C group,respectively. The other 23 rabbits were executed from the16 th day to the 29 th day(median time of 20.5 days), then the experiment was finished. Among the experiment,we had encountered two major technology problems. Firstly, the rabbit body is too small than our people, so we had to choose the right hip to contact the crusher water bag,and the distance between the water bag and the left femoral head were far. Another problem was that the saline was difficult to fill and maintain properly in the vessels in MRCP. The main results were as follows:(1)the survival condition of the three groups was consistent with the changes in the overall situation, and getting worse from the third days, then began to recover from the tenth day. The overall situation of the C group was slightly worse than group A, B.(2)among the 4 indexes of coagulation function, ATPP was failed to detect in many rabbits of the 3 groups, the PT value of group A & C were slightly shorter than group B, and the FIB in group C was slightly longer than group A& B.(3)the MRI quality of 22 rabbits meet the requirements. Compared the 2 times MRI of each rabbit, no significant signal change could be found in T1 W. Meanwhile,congruent increase or decreases of the signal were found in 6 rabbits, T2 fat suppression images, accompanied with intra-articular effusion on the 1, 2 and 3 rabbits in group A,B and C, respectively.(4) The common iliac artery and external iliac artery were 100%showed in MRCP and CTA. The successful display rate of internal iliac artery and iliac artery was 100% and 95.24% in CTA, 30.43% and 73.91% in MRI, respectively.52.38% and 78.57% of the medial femoral artery and the lateral femoral artery were showed in CTA respectively, but all failed to display in MRCP.( 5) Mico CT examination showed that the value of Tb.sp in the left femoral head of group C were less than group A, but higher than the group B, The value of Tb.Th in group C were lower than group A, but close to group B, The BMD of group C were higher than group A, close to group B. Statistical significance of the differences could be found on several indicators between the groups.(6)Negative results of bone necrosis occurred in 3 cases(5 sides) in group C, and 3 cases(4 sides)in group B. Only 1 case showed positive results of osteonecrosis in group A(just 1 side).Conclusion(1) Clinical extracorporeal shock wave equipment could be used to attack the femoral head of rabbits, but it was difficult to ensure the position of target accurately.In addition, the body at the same side of the femoral head as the target point could not be able to close to the water bag, thus the path of the wave was extended. Those factors might be the main reasones of unremarkable differences displayed between the left and right femoral head of the rabbits which accepted ESW intervene.(2) The observation techniques designed in the experiment could reflect the changes in the general body state and the local femoral head. Among them, Micro-CT could sensitively reflect the changes of the micro structure of the femoral head.Compared with MRCP, conventional CTA were better for the presentation of the vessels of the femoral head in rabbits. But the MRCP was very sensitive to liquid, if the problem of inadequate intravascular water filled were solved, MRCP might show excellent performance in the detection of the rabbit vessels.(3) The effect of ESW(14w, 1000 times)impacted on the femoral head mainly displayde as the performance of bone injury, and the enhancement of bone repair function after injury, and the incidence of bone necrosis was decreased, but not increased occurred in bilateral femoral head. Perhaps the reason dued to the problems of the ESW operation, or the interaction between ESW and hormone or endotoxin, but not clearly until now.(4) After intervention with ESW(14w, 1000 times) on the femoral head of ONFH rabbits, the blood coagulation function of the rabbits were greatly affected,mainly displayed as alleviation of the high blood coagulation state induced by LPS.The effection might be related to the changes of the survival scores of those animals,and also might be the reason why no significant differences were found between the left and right femoral head, but the specific mechanism is yet to be further studied. |
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