Inducing a femoral head necrosis model by microwave heating:Screening of optimal temperature and time / 中国组织工程研究

ABSTRACT

BACKGROUND:The existed femoral head necrosis(FHN)model can not reflex the clinical necrosis of femoral head correctly.Microwave heating provides a new approach for model preparation.but the concrete standard remains uncertain.OBJECTIVE:To study the optimal temperature and time jn preparing a FHN model induced by microwave heating.METHODS:Totally 48 rabbits were randomly divided into 4 groups on the basis of the microwave temperature(50,55,60℃)and heating time(10,20 minutes).The microwave antenne was inserted into the rabbit femoral head.The rabbits were sacrificed immediately and at 1,2,4,8 and 1 2 weeks after operation.A series of examinations were performed including gross observation,X-ray.histology and MRI to observe the femoral head necrosis and repair status.RESULTS AND CONCLUSION:Marrow partially solidified in the group(50℃,10 minutes)at 1 week,and the osteonecrosis returned to normaI at 8 weeks after operation.1n the group(55℃,10 minutes),marrow was completely coagulated at 1 week and low signal on T1 weighted images and increased signal on T2 images were identified at 2 weeks.Osteonecrosis and repair occurred at the same time at 4 weeks.At 12 weeks,the osteonecrosis continued and the repair stopped,and the femorel heads started to collapse.All femoral heads collapsed at 8 weeks in group(50℃,20 minutes)and group(60℃,10 minutes).Accordingly.microwave heating is a good method in developing FHN model.55℃ and 10 minutes are the optimal temperature and time for the development of FHN model of rabbits induced by microwave heating.