Protease-induced Emphysema And The Early Preliminary Morphological Change Of Heart And Large Blood Vessel Secondary To The Emphysema In A Minipig Model: An Experimental Study

Objective：To investigate the feasibility of establishing emphysemamodel through intratracheal instillation of porcine pancreatic elastase andpapain in minipigs.Methods：A total of15healthy minipigs were enrolled into this study.Emphysema was induced by porcine pancreatic elastase and papain once aweek for20weeks.The minipigs were firstly endotracheal intubated undergeneral anesthesia,and then injected with6U/kg of papain.Porcine pancreaticelastase had been injected with300U/kg after3days. On0,5th,10th,15th and20th weekend after the beginning of the modeling, all animals underwentchest CT scan and lung function examination. Then,the pulmonary averageCT density and the markers of lung function such as total lung capacity(TLC),functional residual capacity (FRC), inspiratory resistance (Ri) andexpiratory resistance (Re) were acquired and were analyzed. The pathologicalchanges of their lungs were observed by light and electron microscope.Result：1.During the follow–up weekends,5minipigs died of infection,4died of causes unrelated to the experimental protocol.2.With the progress ofmodeling,TLC,FRC,Ri,and Re increased. They had statistically significantdifferences（P＜0.05).3.CT scanning showed that transparency increased andthe pulmonary markings peripheral decreased as emphysema-likeimaging.4.Histological results showed that alveolar wall was thinner, alveolarectasiaed and partially coalesced.Conclusion：The intratracheal injection of porcine pancreatic elastaseand papain can successfully make the emphysema model in minipig. Objective：To evaluate preliminary morphological change of heart andlarge blood vessel secondary to the emphysema through CT scanning.Method：A total of15healthy minipigs were enrolled into this study.Emphysema was induced by porcine pancreatic elastase and papain once aweek for20weeks. On0and20th weekend after the beginning of themodeling, all animals underwent chest CT scan and lung functionexamination. The markers of lung function and the average diameter of rightventricle and pulmonary artery were acquired,then the data were analyzed.Result：1.20th weekend after the beginning of the modeling,thepulmonary function decreased,CT scanning showed the transparencyincreased and pulmonary markings peripheral decreased as emphysema-likeimaging.2.On0and20th weekend,the average diameter of right ventriclewere21.91±3.68mm and22.53±3.45mm,the pulmonary artery were15.63±2.44mm and17.04±2.11mm.Both are increased.There was significantdifference in diameter of pulmonary artery between lung normality andemphysema (P=0.049) with the Mann-Whitney tests,whereas diameter ofright ventricle was not (P>0.05).3.The diameter of pulmonary artery wascorrelated with Re and TLC（r=0.343,0.421,respectively;all P＜0.05）bySpearman’s rank correlation tests.However,there were no correlations between all the above-mentioned lung functional indexes and diameter ofright ventricle.Conclusion： CT scan could be used to evaluate preliminarymorphological change of large blood vessel secondary to the emphysema.