Effect of oleic acid-induced acute lung injury and conventional mechanical ventilation on renal function in piglets

Background Animal models that demonstrate changes of renal function in response to acute lung injury (ALI) and mechanical ventilation (MV) are few. The present study was performed to examine the effect of ALI induced by oleic acid (OA) in combination with conventional MV strategy on renal function in piglets. Methods Twelve Chinese mini-piglets were randomly divided into two groups: the OA group (n=6), animals were ventilated with a conventional MV strategy of 12 ml/kg and suffered an ALI induced by administration of OA, and the control group (n=6), animals were ventilated with a protective MV strategy of 6 ml/kg and received the same amount of sterile saline. Results Six hours after OA injection a severe lung injury and a mild-moderate degree of renal histopathological injury were seen, while no apparent histological abnormalities were observed in the control group. Although we observed an increase in the plasma concentrations of creatinine and urea after ALI, there was no significant difference compared with the control group. Plasma concentrations of neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C increased (5.6 +/- 1.3) and (7.4 +/- 1.5) times in the OA group compared to baseline values, and were significantly higher than the values in the control group. OA injection in combination with conventional MV strategy resulted in a dramatic aggravation of hemodynamic and blood gas exchange parameters, while these parameters remained stable during the experiment in the control group. The plasma expression of TNF-alpha and IL-6 in the OA group were significantly higher than that in the control group. Compared with high expression in the lung and renal tissue in the OA group, TNF-alpha and IL-6 were too low to be detected in the lung and renal tissue in the control group. Conclusions OA injection in combination with conventional MV strategy not only resulted in a severe lung injury but also an apparent renal injury. The potential mechanisms involved a cytokine response of TNF-alpha and IL-6 in plasma, lung and renal tissues.