The Experimental Study In Treatment Of Rabbit External Ear Canal Stenosis By Nitinol Alloy Memorial Stent

[Objective] To establish an animal model for external ear canal(EEC) stenosis and to observe the different treating effect by nitinol alloy memorial stent and silastic tube.[Method] Full ringed skin defect was created in the external ear canal of 24 New Zealand rabbit. The wound was 2cm in length and began from the placket of the ear. 0.5% oculentum aureomycini was applied to the wounds.. In order to judge whether the EEC cicatrical stenosis happened, measuring of the diameters of the EEC by verner caliper was carried out in the 0,15,30,45,60 days after operation, HE coloration was used to study fibroblast hyperplasty and RT-PCR was applied to detecting the TGFβ1mRNA expression. By this means judging whether the EEC cicatrical stenosis was happened. After two months 16 well-made rabbits models were divided into two groups by random. One group was planted skin on the EEC wound and the other group was naked. By self-comparison method nitinol alloy memorial stent were planted in a rabbit model's one EEC and silastic tube in the other. While 5,15,30,60 days later the diameter of the external ear canal (with two material planted) were measured respectively in the skin-planting group. In the naked group scar tissues from external ear canal were harvested and tested separately according to the planting material. HE coloration were used to study fibroblast hyperplasty and IH,RT-PCR were applied to detecting the TGFβ1 protein and TGFβ1mRNA expression. The two brackets were compared according to their effect to scar hyperplasty.[Result]1,The external ear canal cicatrical stenosis model was made successfully with 16 New Zealand rabbits (66.7%) . In the model rabbit HE coloration was found fibroblast cell hyperplasia obviously and RT-PCR also show the increase of TGFβ1 mRNA expression. 2,The EEC diameters in nitinol alloy memorial stent group were found more spacious than the silastic tube group. 3,HE coloration showed the fibroblast hyperplasia were more mitigatory in the nitinol alloy memorial stent group. Immunehistology,RT-PCR found the TGFβ1 protein and TGFβ1mRNA expression were low in the same group.[Conclusion]1,External ear canal cicatrical stenosis can be created by operation. The NewZealand rabbit can be used as a external ear canal stenosis model 2,The nitinol alloy memorial stent shows obvious superiority over silastic tube in external ear canal stenosis therapy.