Traditional Chinese medicine, Qing Ying Tang, ameliorates the severity of acute lung injury induced by severe acute pancreatitis in rats via the upregulation of aquaporin-1

Abstract

Aquaporin-1 (AQP-1) is expressed in lung endothelial cells and regulates water transport; thus, AQP-1 plays an important role in a number of edema-associated lung diseases. Qing Yin Tang (QYT), a traditional Chinese medicine, has been shown to effectively reduce the mortality rate of acute lung injury (ALI) induced by severe acute pancreatitis (SAP). The current study aimed to investigate the detailed mechanisms underlying the effects of QYT on ALI induced by SAP, particularly the effects on the expression levels of AQP-1 in the lung tissue. ALI was established in Wister rats who were subsequently divided into four groups: SHAM, ALI, dexamethasone (DEX) and QYT groups (n=8 per group). In the QYT group, 20 ml/kg QYT was administered by gavage immediately following the induction of SAP. Blood and lung tissues were collected 8 h following the induction of pancreatitis. The lung wet/dry ratio, as well as the levels of blood gases, serum amylase and tumor necrosis factor-α (TNF-α), were measured at 4, 8 and 12 h following SAP-associated ALI induction surgery. The expression levels of AQP-1 in the lung tissue were detected by quantitative polymerase chain reaction, immunohistochemistry and western blot analysis. No statistically significant differences were observed with regard to the levels of serum amylase, wet/dry ratio, partial pressure of oxygen, serum TNF-α and pathological changes in the pulmonary tissue between the QYT and DEX groups; however, a statistically significant difference was observed when compared with the ALI group. The expression levels of AQP-1 significantly increased (P<0.05) and lung edema was alleviated in the QYT and DEX groups, when compared with ALI group. Therefore, the expression level of AQP-1 is associated with pulmonary edema. QYT protects the lungs from injury induced by SAP via the upregulation of AQP-1, which suppresses TNF-α expression.

Keywords: acute lung injury; aquaporin-1; qing yin tang; severe acute pancreatitis.

Figure 1

AQP-1 mRNA expression in the lungs of rats in the (1) SHAM, (2) acute lung injury, (3) dexamethasone and (4) Qing Yin Tang groups. β-actin served as the control. AQP-1, aquaporin-1.

Figure 2

(A) Western blot analysis and (B) semi-quantitative analysis of the protein expression levels of AQP-1 in the (1) SHAM, (2) ALI, (3) DEX and (4) QYT groups. β-actin served as the control. AQP-1, aquaporin-1; ALI, acute lung injury; DEX, dexamethasone; QYT, Qing Yin Tang. ^*P<0.05 compared to ALI group; ^**P<0.01 compared to ALI group.

Figure 3

Pathological images of the lungs (magnification, ×50) in the (A) SHAM, (B) acute lung injury, (C) dexamethasone and (D) Qing Yin Tang groups.