The Role Of Phospholipase A₂ In Bacterial And Non-bacterial Inflammatory Exudate Fluild Of Rat

Objective: To explore the role of phospholipase A₂ (PLA₂) in bacterial and non-bacterial inflammatory exudate fluild of rat. To study bactericidal effect of different types of PLA₂ on different types and different phases of inflammatory exudate fluild. To get further understanding of the role of PLA₂. Methods: Bacterial and non-bacterial inflammatory peritoneal exudates were elicited in rat by intraperitoned injection of S. aureus and sterile physiological saline supplemented with glycogen. After injection, inflammatory exudates were collected from the peritoneal cavity on different phases. We counted the cellar numbers, stained the smears, and measured the bactericidal activities, PLA₂ activities and PLA₂mRNA of inflammatory peritoneal exudates from rat peritoneal cavity,in addition, we added EGTA to inhibit the bactericidal activities of it. Results:(1) After injection of bacteria, on different types and different phases of inflammatory exudate fluild, the bactericidal activities, PLA₂ activities ,PLA₂ mRNA and cellular types were different in inflammatory peritoneal exudates. The bactericidal activities and PLA₂ activities rose to peak at 24h.At 0h , PLA₂mRNA was not found and the cellular types were almost normal macrophages .At 4h and 24h, the cellular types were almost exclusively of polymorphonuclear leukocytes.â…¡PLA₂ and â…£PLA₂ could be found, and â…¤PLA₂ could not be found. At 48h and 72h, the cellular types were almost activated macrophages, not only â…¡PLA₂ and â…£PLA₂ but also â…¤PLA₂ could be found. (2) After injection of glycogen, the bactericidal activities and PLA₂ activities rose to peak at 72h.At 4h, the cellular types were almost exclusively of polymorphonuclear leukocytes.â…¡PLA₂ and â…£PLA2 could be found, and â…¤PLA₂ could not be found. After 24h, the cellular types were almost activated macrophages, not only â…¡PLA₂ and â…£PLA₂ but also â…¤PLA₂ could be found. Bacterial and non-bacterial inflammatory peritoneal exudates had possessed potent bactericidal activities towards Staphylococcus aureus and other gram-positive bacteria. So did towards Gram-negative bacteria, the activity against gram-negative bacteria was due to PMN-derived bactericidal/permeability-increasing protein (BPI). And bactericidal activities of inflammatory peritoneal exudates could be inhibited by EGTA. Conclusions: PLA₂ play an important role in bactericidal effect of exudate fluild of bacterial and non-bacterial inflammation of rat.