The Therapeutic Effect And Mechanism Of Cryotherapy Of Benign Airway Stenosis By A New Cryoprobe

Objective:The animal model of benign airway stenosis was treated with new cryopreservation probe by bronchoscopy to explore the mechanism of granulation tissue proliferation and cryopreservation,and to evaluate the therapeutic effect of a neotype cryoprobe probe on benign airway stenosis.55 healthy beagle dogs were selectde.Among them,30 beagle dogs were used to study the mechanism of cryotherapy,and 25 beagle dogs were used to study thetherapeutic effect of a neotype cryoprobe.1.Mechanism of granulation hyperplasia and cryotherapyMethods:（1）The right posterior lobe bronchus was the therapeutic side and the left posterior lobe bronchus was the control side.（2）The bilateral posterior lobar bronchus of the dog were APC cauterized to establish a model of benign airway stenosis,and on the 7th day after APC operation,the right posterior lobar bronchus of the dog were treated with cryotherapy.（3）The dogs in each group were observed with optical microscopy at the corresponding time point.The bronchoscopy was performed to observe the bronchi at each time points.Immunohistochemical method was used to detect the expression of IL-1β、IL-6、TNF-α、TGF-β₁、VEGF-A and CD105 in bronchial tissues.Results:（1）Optical Mirror Observation:After APC operation,the bronchial mucosa and submucosal layer were damaged,the submucosal connective tissue and cartilage were not damaged,and there was no difference between the control side and the treatment side.（2）Neonatal microvascular observation:The number of microvessels in the treated collateral trachea tissue was lower than the control side（p<0.05）on the 14th day after APC operation.（3）IL-1β、IL-6、TNF-α、TGF-β₁ and VEGF-A expression in bronchial tissues:The expression level of IL-6、TNF-α、TGF-β₁ and VEGF-A in the control bronchial tissue was increased after APC operation;on the 14th day after operation,VEGF-A and IL-6 expression level in the treated collateral trachea tissue was lower than that in the control side at the same time.2.The treatment effect of a neotype cryoprobeMethods:（1）The right posterior lobe bronchus was the therapeutic side and the left posterior lobe bronchus was the control side.（2）Except for the normal group,the bilateral posterior lobar bronchus of the dog were APC cauterized to establish a model of benign airway stenosis,and on the 7th day after APC operation,the right posterior lobar bronchus of 14d group,21d group and 28d group of dogs were treated with cryotherapy.（3）The bronchoscopy was performed to measure the inner diameter of the bronchi at the 7th,14th,21th,28th day.The dogs were executed at the corresponding point to observe the gross specimens;the bronchoscopy was performed to observe the bronchi at each time points.Immunohistochemical method was used to detect the expression of IL-1β、IL-6、TNF-α、TGF-β₁ and VEGF-A in bronchial tissues.Results:（1）Bronchoscope observation（1）General observation under bronchoscopy:There was no significant difference in preoperative,postoperative 7th,14th,21st day between control side and treatment side bronchial manifestations.The control collateral trachea was significantly smaller than the treated side on the 28th day after operation.（2）Measurement of bronchial diameter:There was no significant difference between the treatment of bronchioles stenosis on the 7th,14th and 21st days after APC operation（p>0.05）,and there was significantly difference in diameter between left and right bronchi at the 28th day after APC operation（p<0.05）.（2）Histopathological observation of bronchus（1）Gross specimen observation:There was no difference between the control side and the treatment side bronchus.（2）Observation by light microscope:Histological observation:There was no difference in the control side and treatment side bronchial on the 7th and 14th days after operation.The treatment side recovered faster than the control side bronchial layers on the 21st and 28th days after operation.（3）The expression levels of IL-1βand TGF-β₁ in treated bronchial was lower than control bronchial on the 21st and 28th days after APC operation.The expression levels of IL-6 in treated bronchial was lower than control bronchial on the 14st and21th days after APC operation.The expression levels of TNF-αin treated bronchial was lower than control bronchial on the 28th days after APC operation.The expression levels of VEGF-A in treated bronchial was lower than control bronchial on the 14st、21th and 28th days after APC operation.3.Conclusion:（1）Overexpression of IL-6、TNF-α、TGF-β₁ and VEGF-A can promote scar tissue formation.Cryotherapy can reduce the expression level of VEGF-A、IL-6,inhibit granulation tissue proliferation.（2）The neotype cryoprobe is effective in treating benign airway stenosis caused by granulation hyperplasia.It also confirms that cryotherapy is a non-immediate treatment.