The measurement of plasma MMP-2 and its clinical significance in newborn infants with acute lung injury

Objective To study the level and its clinical significance of matrix metalloproteinase-2 (MMP-2) in plasma of newborns with acute lung injury (ALI). Methods There were 20 neonates admitted to this study that met the diagnostic criteria of ALI and needed mechanical ventilation as experimental group; their primary diseases included meconium aspiration syndrome (MAS),neonatal asphyxia,pneumonia,pulmonary hemorrhage and septicemia. The plasma MMP-2 levels were measured by ELISA at 1h before initiation of mechanical ventilation,12 h after initiation of mechanical ventilation,72 h after discontinuation of mechanical ventilation and at time of discharge; the arterial blood gases were measured at the same time when MMP-2 levels were drawn. 10 healthy neonates were admitted to this study as control group and their MMP-2 levels were measured once. Results It was found that the MMP-2 levels of infants in experimental group were significantly higher at 12 h after initiation of mechanical ventilation than those at 1 h before initiation of mechanical ventilation (P0.01),it was significantly lower at 72 h after discontinuation of mechanical ventilation than those before and after initiation of mechanical ventilation (P0.01); it was also significantly lower at the time of discharge than those at 72 h after discontinuation of mechanical ventilation (P0.01),but there was no significant differences between the experimental group and the control group (P0.05) at discharge. There was no significant differences among infants with different primary diseases (P0.05).The plasma MMP-2 levels showed negative correlation to the oxygen index of infants in the experimental group (r=-0.596,P0.01);the plasma MMP-2 levels at before initiation of mechanical ventilation were positively correlated to the length of hospitalization and the duration of requiring mechanical ventilation (rd=0.690,rh=0.720); the plasma MMP-2 levels of infants using non-invasive ventilators at before and after initiation of mechanical ventilation were markedly lower than those using invasive ventilators (P0.05). Conclusion MMP-2 is involved in the pathophysiologic process of ALI and its plasma level is related to the severities of ALI. It is beneficial to monitor the dynamic changes of plasma MMP-2 levels to evaluate the progress of ALI and to support the diagnosis and treatment of the disease.