[Expression of secretory type II phospholipase A₂ in acute lung injury following acute pancreatitis and interventional effect of Qingyi decoction on it].

Objective: To investigate the expression of secretory type II phospholipase A(2) (sPLA(2)-II) in lung of rats with acute lung injury (ALI) complicating severe acute pancreatitis (SAP), and the effect of Qingyi decoction (QYT) on ALI.

Methods: Thirty Sprague Dawley (SD) rats were randomly divided into three groups: sham operation (SO) group, model group and QYT group, with 10 rats in each group. SAP model was reproduced by reverse injection of sodium deoxycholate into the common bile- pancreatic duct of rats. The pancreas of rats was just exposed in SO group. QYT (10 ml/kg) was gavaged 30 minutes and 12 hours after SAP was induced in QYT group. The blood gas analysis was performed 24 hours after operation. Serum amylase (AMY) levels, sPLA(2) and lung wet/dry ratio (W/D) were determined. The sPLA(2)-II mRNA and sPLA(2)-II protein expression in lung were detected by reverse transcription- polymerase chain reaction (RT-PCR) and Western blotting. The pathological changes in lung and pancreas were observed.

Results: Compared with SO group, the levels of arterial partial pressure of oxygen (PaO(2)) and pH value in model group were significantly decreased [PaO(2) (mm Hg, 1 mm Hg=0.133 kPa): 79.24±5.84 vs. 96.78±3.81, pH value: 7.269±0.054 vs. 7.391±0.054], arterial partial pressure of carbon dioxide (PaCO(2)), the serum levels of AMY, W/D ratio and the serum levels of sPLA(2) were significantly increased [PaCO(2) (mm Hg): 47.57±2.55 vs. 27.69±1.02, AMY (U/L): 7 144.19±727.91 vs. 1 193.41±192.54, W/D ratio: 8.57±2.45 vs. 3.70±0.90, sPLA(2) (nmol×min(-1) ×ml(-1)): 45.13±6.05 vs. 29.94±6.39], the expression of sPLA(2)-II mRNA (1.28±0.21 vs. 0.80±0.08) and protein were significantly increased (all P <0.05). Compared with model group, blood PaO(2) and pH value were significantly increased [PaO(2): (88.16±5.07) mm Hg, pH value: 7.322±0.039], the PaCO(2), the serum levels of AMY, W/D ratio and the serum levels of sPLA(2) in QYT group were significantly decreased [PaCO(2): (33.13±2.14) mm Hg, AMY: (4 283.51±527.52) U/L, W/D ratio: 4.05±0.52, sPLA(2): (28.00±4.78) nmol×min(-1) ×ml(-1)], and the expression of sPLA(2)-II mRNA (0.89±0.08) and protein were significantly decreased (all P <0.05). The pathological changes in lung and pancreas in QYT group were milder than those in SAP group.

Conclusion: The higher expression of sPLA(2)-IIin lung may be one of pathogenetic factors in ALI induced by SAP. Administration of QYT can reduce the injury of lung by decreasing the expression of sPLA(2)-II in transcriptional level and thus protecting pulmonary function.