鸡蛋清溶菌酶对头孢他啶诱导的绿脓杆菌溶解和致炎活性物质释放的抑制作用

Inhibitory effect of egg white lysozyme on ceftazidimeinduced release of inflammatory factor from Pseudomonas aeruginosa

目的 :观察鸡蛋清溶菌酶 (L ZM)与头孢他啶 (CFT)联合应用对绿脓杆菌生长、形态及其致炎活性物质释放的影响。方法 :在肉汤或稀释血液培养的绿脓杆菌液中加入 L ZM或 CFT作用 ,采用营养琼脂平板接种 ,计数各培养管中存活细菌数。将细菌悬液离心 ,将培养上清液加到培养的巨噬细胞中 ,测定其对巨噬细胞肿瘤坏死因子α(TNFα)的诱生能力 ,同时用光学显微镜观察各培养管中细菌的形态。结果 :对 CFT敏感的绿脓杆菌在 CFT2 5和 5 0 m g/ L 作用下 ,可使细菌迅速溶解 ,同时伴大量致炎活性物质 (主要包括内毒素 )释放 ,其培养上清液在体外培养的巨噬细胞上可诱导大量的 TNFα产生 ;L ZM与 CFT联合使用能阻止细菌溶解 ,但仍保持与 CFT单独用药相当的杀菌作用 ,死亡的细菌相互粘连 ,形成聚集体 ,并可降低对巨噬细胞的激活 ,减少TNFα等炎性因子的产生。对 CFT耐药的绿脓杆菌在 CFT的作用下 ,虽然细菌溶解不明显 ,但致炎活性物质的释放也增高 ;L ZM与 CFT联合用药也可降低致炎活性物质的释放。在采用血液培养系统进行的实验中 ,也得到类似结果。结论 :L ZM与 CFT联合使用能阻止细菌溶解 ,降低细菌致炎活性物质 (主要包括内毒素 )的释放 ,从而可能减轻内毒素血症。

Objective:To investigate the effects of egg white lysozyme(LZM) in combination with βlactam antibiotics on the growth,the morphological changes and the release of inflammatory substances of Pseudomonas aeruginosa.Methods:Pseudomonas aeruginosa which was cultured in the nutrition broth or the diluted rabbit blood was treated with ceftazidime alone or in combination with LZM.The viability of the bacteria in the various cultures was determined.The supernatants from the bacterial cultures were collected by centrifuge and added into RAW 264 7 cells,a macrophage cell line.Tumor necrosis factorα(TNFα) productivity of the supernatants from the cell culture was assayed with enzymelinked immunosorbent assay (ELISA) methods.In addition,the morphological changes of the bacteria were observed.Results:A sensitive strain of Pseudomonas aeruginosa could be rapidly lysed and simultaneously a large amount of inflammatory factor was released from bacteria into the culture supernatant after the bacteria were treated with ceftazidime 25 and 50 mg/L. Those supernatants induced a plenty of TNFα production from RAW 264 7 cells.LZM in combination with ceftazidime blocked the lysis of bacteria without disturbance of bactericidal effect of ceftazidime .The obituary bacteria conglutinated each other and forming a lot of large congeries.As a result,the combinative application of LZM with ceftazidime depressed the following activation of macrophages assessed by TNFα production.Another strain of Pseudomonas aeruginosa ATCC 27853 showed to be resistant against ceftazidime.Though the treatment of bacteria with ceftazidime caused no obvious lysis,the release of inflammatory factor significantly increased,and the release could be suppressed by the combination of ceftazidime with LZM.A study by using diluted rabbit blood culture showed the similar results.Conclusions:The combination of LZM with ceftazidime can prevent bacteriolysis and decrease the release of inflammatory factors (mostly including endotoxin),and consequently abate endotoxemia.