蛇毒抗菌肽OH-CATH对大肠杆菌引起的导尿管感染的保护作用

Protective effects of snake venom antimicrobial peptide OH-CATH on E.coli induced rabbit urinary catheter infection

目的:探讨蛇毒抗菌肽OH-CATH在家兔留置导尿管引起泌尿系感染模型中的抗感染作用。方法:利用大肠杆菌标准株(E.coli ATCC 25922)作为感染细菌,几丁糖凝胶作为生物涂层建立兔留置导尿管感染模型,随机分组,同时给予蛇毒抗菌肽OH-CATH干预,头孢哌酮钠作为对照,分别于模型建立后1、5、10 d采集尿液和血液,行尿培养和细胞因子测定;模型建立后10 d对导尿管进行细菌培养和扫描电镜观察细菌生物膜(biofilm)的形成情况,HE染色病理检查观察膀胱感染情况。结果:头孢组和抗菌肽组对biofilm有明显的抑制作用,biofilm表面的悬浮细菌数量少,实验动物的感染较轻。抗菌肽组TNF-α、IL-1α较其他3组明显升高(P<0.05)。结论:用蛇毒抗菌肽OH-CATH预处理导尿管可显著抑制biofilm的形成,调节实验动物机体免疫,减轻实验动物的感染,实现对实验动物的保护作用。

Objective To investigate the anti-infectious effects of snake venom antimicrobial peptide OH- CATH on rabbit urinary catheter infection induced by E.coli. Methods The rabbit urinary catheter infection models were constructed by E.coli ATCC 25922 used as infected bacteria and chitosan gel used as biological coating; and were randomized to receive snake venom antimicrobial peptide OH-CATH intervention or cefoperazone sodium as controls. On day 1, 5 and 10 after modeling, blood and urine were collected to undergo urine culture and cytokine assays. On day 10 after modeling, the urinary catheter were explanted to receive bacterial culture, scanning electron microscopy was used to observe the formation of bacterial biofilms, and bladder infection was observed by pathological examination of HE staining. Results Biofilm was significantly inhibited by both cefoperazone and antimicrobial peptide, and the number of suspending bacterial counted on the surface of biofilm was relatively lower, which indicated that the severity of infection in the models was relatively mild. The expressions of TNF-α and IL-1α in antimicrobial peptide group were increased significantly （P 〈 0.05 ）. Conclusions The snake venom antimicrobial peptide OH-CATH pretreating urinary catheter was able to exert a predominant inhibitory effect against the formation of biofilm, to regulate the immunity, to reduce the infection and to act as a protective agent for the animal models.