Effects of MMP-9 inhibition by doxycycline on proteome of lungs in high tidal volume mechanical ventilation-induced acute lung injury

Background: Although mechanical ventilation (MV) is a major supportive therapy for patients with acute respiratory distress syndrome, it may result in side effects including lung injury. In this study we hypothesize that MMP-9 inhibition by doxycycline might reduce MV-related lung damage. Using a proteomic approach we identified the pulmonary proteins altered in high volume ventilation-induced lung injury (VILI). Forty Wistar rats were randomized to an orally pretreated with doxycycline group (n = 20) or to a placebo group (n = 20) each of which was followed by instrumentation prior to either low or high tidal volume mechanical ventilation. Afterwards, animals were euthanized and lungs were harvested for subsequent analyses. Results: Mechanical function and gas exchange parameters improved following treatment with doxycycline in the high volume ventilated group as compared to the placebo group. Nine pulmonary proteins have shown significant changes between the two biochemically analysed (high volume ventilated) groups. Treatment with doxycycline resulted in a decrease of pulmonary MMP-9 activity as well as in an increase in the levels of soluble receptor for advanced glycation endproduct, apoliporotein A-I, peroxiredoxin II, four molecular forms of albumin and two unnamed proteins. Using the pharmacoproteomic approach we have shown that treatment with doxycycline leads to an increase in levels of several proteins, which could potentially be part of a defense mechanism. Conclusion: Administration of doxycycline might be a significant supportive therapeutic strategy in prevention of VILI.