清胰汤对大鼠急性胰腺炎肺损伤时SP-A表达的影响

Influence of Qingyitang on surfactant protein A expression in severe acute pancreatitisinduced lung injury in rats

目的:探讨重症急性胰腺炎(SAP)肺损伤(ALI)时肺表面活性蛋白A(SP-A)的表达及其在ALI发病中的作用,并观察清胰汤对SP-A表达和病情转归的影响.方法:采用胆胰管内逆行注入1.5%去氧胆酸钠建立大鼠SAP时ALI模型.将SD大鼠随机分为假手术组(n=10)、模型组(n=10)和清胰汤组(n=10).假手术组仅行剖腹术,翻动胰腺.清胰汤组在建立SAP模型后30 min和12 h清胰汤ig(10 mL/kg).各组大鼠在术后24 h测PaO_2和血淀粉酶.应用逆转录聚合酶链式反应(RT- PCR)检测肺SP-A mRNA的表达强度,Western- blot观察SP-A表达,并观察胰、肺病理变化及肺泡Ⅱ型上皮细胞的电镜下变化.结果:模型组血淀粉酶(7144.19 U/L±727.91 U/L)显著高于清胰汤组(4283.51 U/L±527.52 U/L)和假手术组(1193.41 U/L±192.54 U/L,P<0.01).模型组PaO_2显著低于假手术组和清胰汤组(79.24±5.84 vs 96.78±3.81.79.24±5.84 vs 88.16±5.07,P<0.01).清胰汤组肺SP-A mRNA表达显著高于模型组(P<0.01),肺SP-A蛋白的表达显著高于模型组,SP-A mRNA的表达与肺损伤的程度呈负相关.清胰汤组胰、肺病理及电镜改变较模型组减轻.结论:SAP时肺泡Ⅱ型上皮细胞功能受损,SP-A mRNA表达降低导致急性肺损伤的机制之一.清胰汤能保护肺泡Ⅱ型上皮细胞功能,恢复SP-A mRNA正常表达,维持肺泡功能,从而对肺组织起保护作用.

AIM： To investigate the expression of surfactant protein A （SP-A） in the lungs of rats with severe acute pancreatitis （SAP）, and the effect of Qingyitang on acute lung injury （ALI） induced by SAP. METHODS： SD rats were randomly divided into sham-operation group （SO, n = 10）, SAP model group （SAP, n = 10） and Qingyitang group （QYT, n = 10）. Severe acute pancreatitis was induced in the SAP and QYT groups. Sham operations were only performed on rats in the SO group. QYT （10 mL/kg） was intragastrically administered 30 min and 12 hours after SAP was induced in the QYT group. Serum amylase （AMY） levels, PaO2 and lung wet/dry ratio （W/D） were determined. The level of SP-A mRNA expression in lung was detected by reverse transcription polymerase chain reaction （RT-PCR）. SP-A protein in lung was detected by Western blotting. Pathological changes in the pancreas, lung and alveolar type II cells were observed 24 hours after the establishment of the model. RESULTS： The serum levels of AMY （7144.19 U/L ± 727.91 U/L） in rats of the SAP group were remarkably higher than those in rats of the QYT （4283.51 U/L ± 527.52 U/L） and SO （1193.41 U/L ± 192.54 U/L, P 〈 0.01） groups. The levels of PaO2 in rats of the SAP group （79.24 mmHg ± 5.84 mmHg） were lower than those in rats of the SO （96.78 mmHg ± 3.81 mmHg） and QYT （88.16 mmHg ± 5.07 mmHg, P 〈 0.01） groups. The expression levels of SP-A mRNA and SP-A in the rat lungs of the SAP group were significantly decreased compared with those in rats in the SO and QYT groups （P 〈 0.01）. The pathologic changes of the pancreas, lung and alveolar type II cells in rats of the QYT and SO groups were milder than those in rats of the SAP group. CONCLUSION： The levels of SP-A decrease remarkably in rats with ALI induced by SAP. Administration of QYT reduces injury of lung by protecting alveolar type II cells and increasing the expression of SP-A.