The Mechanism, Prophylaxis And Treatment Of Acute Lung Injury Induced By Endotoxic Shock

Part â…  The Activation of Phospholipase A2 and Acute LungInjury Induced by Endotoxic ShockObjective To study the mechanism of acute lung injury induced by endotoxic shock and to explore the role of phospholipase A2 (PLA2) in the inflammatory progress.Method Using a rat model of acute lung injury induced by endotoxic shock, animals were divided randomly into sham operation group and endotoxic shock group. Mean artery pressure (MAP) was measured every half an hour. Serum, lung tissue and bronchoalveolar lavage fluid (BALF) were collected after 6 hours. The parameters of lung-body coefficient, lung penetrating index (LPI), protein content inBALF, activity of NOS and PLA2 in lung tissue were measured, respectively. The gene expression of secretory phospholipase A2 type â…¡A (sPLA2-â…¡A) in lung tissue was determined by the way of RT-PCR. Furthermore, the histologic damages of lung were compared with those of sham operation group after stained by hematoxylin and eosin. Particularly, the correlation between the activity of PLA2 and lung coefficient, LPI, protein content in BALF, activity of NOS in lung tissue were analysed, respectively.Results Endotoxin can lower MAP and increase the levels of lung-body coefficient, LPI, protein content in BALF, activity of NOS and PLA2 in lung tissue, and mRNA expression of sPLA2-â…¡A. Enough morphological evidence can be found in pathology sections. Furthermore, there was positive correlation between the activity of PLA2 and lung-body coefficient, LPI, protein content in BALF, activity of NOS in lung tissue, respectively.Conclusion The activation of PLA2 to trigger the inflammatory response is the premise of lung injury. Secretory phospholipase A2 type â…¡A which can damage the pulmonary surfactant is the fundamental factor of lung injury. KEY WORDS PLA2,endotoxin,shock,lung injury...