The Influence Of Piperacillin And Polymyxin B On The Release Of Endotoxin And Blood Clotting Function In Pneumonic Rats

OBJECTIVE: To investigate endotoxin release and its plasma d-dimer levels and coagulation parameters in immunosuppression pneumonic rats used different antibacterials independently or in combination, to provide information for rational use of antibiotics in clinic practice.METHODS: Hypodermic injection of dexamethasone (2mg/kg of body weight) in the morning and intraperitoneal injection of cyclophosphamide (15 mg/kg of body weight) in the afternoon once a day for 4 days were performed in 40 health wistar rats, and multidrug resistance pseudomonas aeruginosa pneumonia model was established by intratracheal injection of the bacteria. After 12～14h, all the animals were randomized to receive intraperitoneally isotonic sodium chloride solution (control group), 600mg/kg of piperacillin (PIP group), 20mg/kg of polymyxin B (PMB group), and 600mg/kg of piperacillin plus 20mg/kg of polymyxin B (PIP +PMBgroup), respectively. The amounts of bacteria endotoxin release, plasma DD levels and coagulation parameters were detected 6～8h after antibacterials administration.RESULTS: ① The immunocompromised host (ICH) rats experienced obvious weight loss (239.08±15.48g versus 208.40±12.13g, P<0.01). ② The mean plasma ET level in three treated groups was significantly lower than that of the control group 6～8h after antibacterials administration (control group: 72.299±21.504pg/ml, PIP group: 19.117±6.868pg/ml, PMB group: 23.109±11.775pg/ml and PIP+PMBgroup: 17.965±10.466pg/ml, P<0.01). ③ There were no significant difference of the plasma DD levels and coagulation parameters in the 4 groups (P > 0.05). ④ No correlation is indicated between the plasma ET and DD levels, and the same result between the plasma ET and coagulation parameters. ⑤ Study of pulmonary pathology revealed that the lung tissues of ICH rats were major infiltrated by lymphocytes, capillary congestion and interstitial hemorrhages were obvious.CONCLUSION: ① The plasma ET levels decrease in the group that receive either PIP or PMB or both, and the two kinds of antibacterials have synergistic effect. So when choose antibiotics, we should pay attention to the antibacterial spectrum and antimicrobial activity of the medicine, and we should not take ET as the the most important factor. Sufficient and effective antibacterials can sterilize effectually and suppress producing ET. ② The study shows the two antibacterials used independently or in combination have no influence on the plasma coagulation parameters and DD levels. The two antibacterials within therapeutical dose have no significant influence on the blood clotting function.③ No correlation is indicated between the plasma ET and DD levels, and the same result between the plasma ET and coagulation parameters.