Objective: To study the role of cyclooxygenase (COX) and platelet-activating factor (PAF) in pathophysiologic mechanisms of patients with systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS).
Methods: Twenty-eight adult patients whose diagnosis met American college of chest physicians/society of critical care medicine (ACCP/SCCM) criteria for SIRS and MODS were enrolled for study including 13 cases for SIRS group and 15 cases for MODS group. The normal control group consisted of 11 healthy volunteers who matched with study subjects for age and gender. Enzyme linked immunoadsorbent assay (ELISA) was used to measure the content of COX-2 and the activity of platelet-activating factor acetylhydrolase (PAF-AH) of peripheral blood mononuclear cells (PBMCs). Reverse transcription polymerase chain reaction (RT-PCR) was used to measure the COX-2 mRNA and PAF-AH mRNA expression of PBMCs.
Results: The content of COX-2 and the activity of PAF-AH of PBMCs and the expression of their mRNA in MODS group were higher than those in SIRS group and control group (all P<0.05). There was no significant difference between SIRS group and control group. The content of COX-2 and the activity of PAF-AH and the expression of their mRNA of PBMCs in non-survivors were higher than those in survived patients (all P<0.05). In 3 groups, positive correlation was found between the COX-2 content and PAF-AH activity (r=0.329, P<0.05). The leukocyte count, lymphocyte count, and PaO(2)/FiO(2) of peripheral blood in non-survivors showed no significant difference with those of survived patients (all P>0.05). The blood glucose and creatinine of non-survivors were higher than those of survived patients (P<0.05 and P<0.01). The total CO(2) content (TCO(2)) and pH value of non-survivors were lower than those of survived patients (both P<0.01).
Conclusion: This study shows that COX-2 and PAF-AH play a role in the occurrence of MODS and they can be used as indexes to judge the prognosis of SIRS and MODS. Blood glucose, creatinine, TCO(2) and pH value of blood can be used as other indexes for judging the state and the prognosis of the illness.