Effect of atrial natriuretic peptide on acute lung injury and possible mechanism

    YAN Zhiª²Qiang, LI Zhiª²Chao, LI Zhiª²Bin, SONG Jingª²Chun, WEI Min

    1Department of Pathophysiology, School of Basic Medicine, Fourth Military Medical University, Xi¡¯an 710033, China, 2Clinic, Kashi Military Subregion in Xinjiang, Kashi 844200, China

    ¡¾Abstract¡¿ AIM: To study the protective effect of atrial natriuretic peptide (ANP) on alveolar type¢ò cells (ATª²¢ò) from lipopolysaccharide (LPS) induced acute lung injury (ALI). METHODS: Eighteen rats were divided into 3 groups: Control group were injected physiological saline through jugular, LPS group were injected LPS and physiological saline through jugular and ANP group were injected LPS and ANP through jugular. Four hours later, rats were sacrificed and the bronchoalveolar lavage fluid (BALF) was collected. Surface tension, total phospholipids (TPL), total protein (TP) and maleic dialdehyde (MDA) content of the BALF were measured. The activity of lactate dehydrogenase (LDH) and alkaline phosphatase (AKP) in BALF were detected. RESULTS: Compared with those of control group, LPS can increase the TP content and the activity of LDH [Control Group (4.8¡À1.9) ¦Ìkat/L, LPS Group (8.4¡À1.9) nkat/L in BALF (P<0 .05), which could be reversed by ANP (5.1¡À1.7) ¦Ìkat/L]. TPL [(0.43¡À0.04) vs (0.34¡À0.06) ¦Ìg/kg] increased and surface tension [(19.8¡À2.6) vs (23.3¡À2.9) mN/m] decreased in LPS group (P<0.05), but no difference was found between ANP group [TPL (0.41¡À0.06) ¦Ìg/kg; surface tension (18.6¡À2.9) mN/m] and control group. ANP prevented the increase of the AKP activity [Control Group (0.10¡À0.08) ¦Ìkat/L, LPS Group (0.36¡À0.10) ¦Ìkat/L, ANP Group (0.14¡À0.09) ¦Ìkat/L] and the content of MDA in BALF (P<0.05) induced by LPS. CONCLUSION: ANP can protect the lung from injury by LPS in ALI. One of the most important mechanisms is possibly that ANP can protect the ATª²¢ò and facilitate the secretion of PS. ......