Injuring effect of lipopolysaccharide on alveolar type II cells

AIM: To study the injuring effect of lipopolysaccharide(LPS) on alveolar type Ⅱ cells (AT-Ⅱ) in acute lung injury (ALI). METHODS: Sixteen rats were evenly randomized into 2 groups: control group and LPS group. Control group were injected physiological saline through jugular vein; LPS group were injected LPS through jugular vein. Four hours later, the rats were sacrificed to collect the bronchoalveolar lavage fluid (BALF). Surface tension, total phospholipids(TPL), total protein(TP) and maleic dialdehyde(MDA) contents in the BALF were measured; the activities of lactate dehydrogenase(LDH) and alkaline phosphatase(AKP) in BALF were detected. The pathological features of right lungs were observed under an optical microscope. RESULTS: Compared with control group, LPS could increase the TP content [(28±17) vs (100±32) g/L, P0.05] and the activity of LDH [(4.8±1.9) vs (8.4±1.9) μkat/L]in BALF (P 0.05), and the content of MDA in BALF(P0.05); We could observe the interstitial pulmonary edema in LPS group by the microscopy; TPL could be decreased [(432±45) vs (342±59) μg/kg] and surface tension be increased [(19.8±2.6) vs (23.3±2.9) mN/m] by LPS(P0.05); LPS could increase significantly the activity of AKP[(100±80) vs (360±100) nkat/L] (P0.05). CONCLUSION: LPS can injure the AT-Ⅱand suppress the secretion of pulmonary surfactants in acute lung injury.