The Pathogenesis Of ALI Rats Induced By Different Risk Factors And The Efficacy Of Steroid Therapy

Acute lung injury (ALI) is a serious complication in the patients with critical illnesses. All the clinical reasons can be divided into two cases: a indirect causes originated from outside of the lung and direct insults on the lung. Examples of former ones include systemic sepsis and shock and examples of the latter ones include severe pneumonia, aspiration of gastric contents etc. ALI is a syndrome of pulmonary inflammation characterized by increased permeability of alveolar-capillary. ALI often leads to acute respiratory distress syndrome (ARDS). Despite recent advances in intensive care, mortality rates of patients with ARDS persist at high level, between 40% and 60%. In 1994, the American-European Consensus Conference defined two pathogenetic pathways leading to ARDS: a direct insult, pulmonary ARDS (ARDSp) which directly affects lung parenchyma, and indirect insults,extrapulmonary ARDS (ARDSexp).ARDS is characterized by an acute inflammatory response in the lung parenchyma that is associated with severe injury to the endothelial and epithelial barriers. ARDS involves an intense inflammatory response in the lung, with accumulation of both pro- and anti- inflammatory cytokines in BALF and blood. Although considerable progress has been made in the inflammatory mechanism of ARDS, we still lack the information about the characteristics (such as the permeability to proteins and the contents of the inflammatory mediators) of the inflammation underlying the different causes of ARDS. Despite improvement in supportive care and alleviating symptom, the effective measures directed at modifying the pathogeny and pathogenesis are seldom. The mortality still remains high.The objective of this study include: (1) Establishment of two rat models of ALI induced by intravenous injection of LPS and by infusion of HCl into the...