β_2肾上腺素受体对重症急性胰腺炎大鼠肺脏水清除能力的调节作用

Regulation Role of β_2 Adrenoceptor on Alveolar Fluid Clearance of Severe Acute Pancreatitis in Rats Model

目的探讨β2肾上腺素受体对大鼠重症急性胰腺炎(SAP)肺脏水清除能力的影响。方法建立SD大鼠SAP模型。随机单盲分为假手术组和SAP组,SAP组根据造模后取材时相的不同分为SAP-4 h和SAP-24 h两个亚组。测定左右肺湿干比、肺泡液体清除率(AFC),进一步检测应用β肾上腺素受体激动剂特布他林(terbutaline)和β肾上腺素受体阻滞剂普萘洛尔(propranolol)处理后的AFC。Real-time-PCR方法测定β2肾上腺素受体m RNA在大鼠肺组织中的表达。结果 1双肺湿干比变化:与假手术组比较,SAP组4 h时双肺湿干比明显下降(P<0.05),24 h时下降更明显(P<0.05);各组的双侧肺脏湿干比比较差异无统计学意义(P>0.05)。2 AFC变化:SAP组4 h和24 h时肺的AFC均明显高于假手术组(P<0.05),4 h时升至顶峰(P<0.05),24 h时呈下降趋势(P<0.05);β肾上腺素受体激动剂terbutaline不能进一步提高SAP组4 h和24 h时已升高的AFC(P>0.05),但是抑制剂propranolol可降低SAP组4 h和24 h时已升高的AFC(P<0.05)。3β2肾上腺素受体蛋白m RNA表达情况:与假手术组比较,SAP组4 h和24 h时肺组织中β2肾上腺素受体m RNA水平均明显下降(P<0.05)。结论 SAP会导致双侧肺的液体较正常状态下明显减少,AFC先升高后逐渐下降,从而导致肺损伤逐步发生。β2肾上腺素受体可能参与调节大鼠SAP时肺脏的水清除能力。SAP大鼠肺脏的变化机理十分复杂,还需要更多更深入的研究。

Objective To discuss the effect of β2 adrenoceptor on the alveolar fluid clearance （AFC） of the rats with severe acute pancreatitis （SAP）. Methods SD rats was made to SAP model by injecting taurocholate into biliary- pancreatic duct. These rats were randomly divided into sham operation group and SAP group, the SAP group was divided into subgroups of SAP-4 h and SAP-24 h according to the sampling time after making model. The wet-to-dry ratio, AFC, and AFC affected by β2 adrenoceptor agonist-terbutaline or inhibitor-propranolol were measured in the bilateral lungs. β2 adrenoceptor mRNA expression in the lungs tissues was measured by real-time-PCR. Results Compared with the sham operation group, the wet-to-dry ratio was significantly decreased （P〈 0. 05） and the AFC was significantly increased in the subgroup of SAP-4 h or SAP-24 h （P〈 0. 05）, β2 adrenoceptor agonist-terbutaline couldn＇t increase the AFC of the subgroup of SAP-4 h or SAP-24 h （P〉0. 05）, inhibitor-propranolol could decrease AFC of subgroup of SAP-4 h or SAP- 24 h （P〈 0. 05）. β2 adrenoceptor mRNA was decreased in the subgroup of SAP-4 h or SAP-24 h as compared with the sham operation group （P〈0. 05）. Conclusions Bilateral lung liquid volome induced by SAP is less than the normal lung, AFC is increased in the early period of SAP but decreased in the late period. When the lung injury happens, β2 adrenoceptor might modulate AFC in rats of SAP model. The mechanism of lung injury of SAP is so complex that we need more experiments to be done.