Matrix metalloproteinase-9 as new biomarkers of severity in multiple organ dysfunction syndrome caused by trauma and infection

Multiple organ dysfunction syndrome (MODS) is an important cause of morbidity and mortality in intensive care unit. A severe insult in the form of infection or trauma primes the host immune system so that a subsequent, relatively trivial insult produces systemic inflammation response syndrome, which can lead to MODS and death. Matrix metalloproteinase-9 (MMP-9) is stored in the tertiary granules of polymorphonuclear leukocytes. These cells are key effectors in acute inflammatory diseases, such as sepsis and MODS. Endotoxin leads to rapid release of MMP-9 from these granules in vitro and in vivo. However, the role of this enzyme in MODS, and whether it is associated with organ injury at the early stage of MODS remains unclear. This present work may study role of MMP-9 with the MODS rats that caused by trauma and infection and investigate the mechanism of organ injury at the early stage of MODS. Here, we developed a rat model for MODS caused by trauma and infection and analyzed the dynamic level of MMP-9 and determined the relationship between MMP-9 level and early phase of organ injury in MODS rat. The histological changes in pulmonary, renal, and hepatic tissue were observed by light microscope. The expressions of plasma MMP-9 proteins were detected by an enzyme linked immunosorbent assay and its levels in the pulmonary, renal, and hepatic tissue were detected by using immunohistochemistry, respectively. The results indicated that there were no significant improvements in histopathology of rats in control group. However, the pulmonary, renal, and hepatic damage were serious in MODS groups. The concentration of MMP-9 in plasma and tissues of MODS rats increased markedly at the early stage and were higher than that of the control group. Moreover, the MMP-9 level in plasma positively correlated with the levels of pulmonary, renal, and hepatic tissue. This study clearly shows that MMP-9 is good biomarker to predict the severity of injury organ at the early phase of MODS.