Experimental Study On Effects Of Lung Volume Reduction Surgery On Diaphragmatic Biomechanics In Emphysematous Rabbits

Background and Objective:Chronic obstructive pulmonary disease (COPD) is a disease characterized by airflow limitation that is not fully reversible. The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases. COPD, a major public health problem, is the fourth leading cause of chronic morbidity and mortality in the United States and is projected to rank the fifth in 2020 as a worldwide burden of disease. COPD is closely related to chronic bronchitis and emphysema. Emphysema is characterized by abnormal and permanent dilatation of the distal bronchioles accompanied by destruction of alveolar walls and bronchioles, but not remarkable fibrosis. The pathogenic mechanisms of emphysema, however, are not well known. The establishment of emphysematous animal model is helpful to discover the pathogenic mechanisms. With the development of surgical procedures for treating emphysema, numerous studies have demonstrated that lung volume reduction surgery (LVRS) is a current procedure that could improve quality of life, physiologic status, and survival of patients with severe emphysema. The mechanisms of the benefits have attributed to enhanced elastic recoil, correction of ventilation perfusion mismatch, improved efficiency of respiratory musculature, and improved right ventricular filling. A lot of researches mostly focus on clinical observation of the lung parenchyma itself, respiratory muscles, chest wall, and cardiovascular functions, but there are few applied basic researches on LVRS. The latest studies also prove that emphysema has great effects on the contractility of the diaphragmatic muscle. Diaphragm, one of the major respiratory muscles, has been deeply studied concerning its structures, functions, and metabolism. However, the biomechanical characteristics and the expression levels of cytoskeletal proteins in the diaphragmatic muscle tissues in emphysematous model are not very clear. In order to explore the mechanisms of LVRS for treating emphysema, the experiments were employed...