黄芩素联合头孢他啶对小鼠腹腔铜绿假单胞菌早期生物被膜感染的体内影响

In vivo effect of baicalein combined with ceftazidime on early biofilm infection with Pseudomonas aeruginosain intraperitoneal cavities of mice

目的探讨黄芩素(Baicalein,BCA)联合头孢他啶(CAZ)对小鼠腹腔铜绿假单胞菌早期生物被膜(BF)感染的治疗作用。方法 28只雌性小鼠随机分成空白对照组、BCA组(300 mg/kg.d)、CAZ组(65 mg/kg.d)和BCA(300mg/kg.d)+CAZ(65mg/kg.d)组,每组各7只,以输液管为载体,PAO1野生株为实验菌株,体外培养形成早期铜绿假单胞菌生物被膜,建立腹腔BF感染模型后分别给予BCA灌胃,CAZ腹腔注射,空白对照组给予等量无菌生理盐水腹腔注射,药物作用24h后取出载体经连续稀释法进行细菌活菌计数;在扫描电子显微镜(SEM)下观察载体表面BF的形态变化;腹腔感染组织切片HE染色显微镜下观察组织病理学改变。结果经药物治疗24h后,各药物组载体表面菌落计数均明显少于空白对照组(P<0.01),BCA+CAZ组与CAZ组、BCA组比较菌落计数明显减少(P<0.01);SEM观察发现空白对照组与各药物组比较载体表面BF形成多而稠厚,BCA+CAZ组BF明显稀薄,只见少量细菌黏附;腹腔感染组织病理学表现空白对照组炎症表现最为明显,可见大量中性粒细胞和巨噬细胞浸润;BCA+CAZ组只见轻度炎症反应。结论 BCA单独作用可抑制小鼠腹腔PAE感染早期BF的生长,与CAZ联合应用,CAZ对BF的杀菌作用可明显增强。

OBJECTIVE To explore the effect of baicalein （BCA） combined with ceftazidime （CAZ） on treatment of early biofilm infection with Pseudomonas aeruginosa in intraperitoneal cavities of mice. METHODS A total of 28 female mice were randomly divided into the control group, BCA group（300 mg/kg, d）, CAZ group （65mg/kg. d）, and BCA（300mg/kg. d）plus CAZ（65mg/kg. d）group, with 7 mice in each group. The infusion tube was used as carrier, the PAO1 wild strains were set as the experimental strains. The early biofilm of P. aeruginosa was formed by in intro culture. After the model of intraperitoneal implant BF infection was established, the mice in the BCA- treated group were treated with intragastric administration of BCA, the mice in the CAZ-treated group were trea- ted with intraperitoneal injection of CAZ, and the mice in the control group were treated with intraperitoneal injection of the same amount of sterile saline. The implants were removed out from the peritoneal cavities after the drug treatment for 24 hours, the bacterial colony counting was conducted by using continuous dilution method, the morphological changes of BF on the surfaces of implants were observed under scanning electron microscope （SEM）, and the histopathological changes of tissue sections of abdominal infection were observed under HE staining microscope. RESULTS The bacterial colony counts on surfaces of implants were significantly less in the drug groups than in the control group after the drug treatment for 24 hours （P〈0. 01）5 the bacterial colony counts were significantly less in the BCA plus CAZ group than in the CAZ group and the BCA group （P〈0.01）. The SEM observation showed that the BF formed on the surfaces of implants is much and thick in the control group and the drug groups, the BF of the BCA plus CAZ was remarkably thin, only a few of bacterial adhesions were seen. As for the histopathological manifestations of abdominal infection, the inflammatory manifestations of the control group were the most obvious, and huge amount of infiltrated neutrophils and macrophages were seen; only mild inflammatory reactions were seen in the BCA plus CAZ group. CONCLUSION The single use of BCA may inhibit the growth of BF in intraperitoneal cavities of mice with early P. aeruginosa infection, and its combination with CAZ can remarkably enhance the bactericidal effect of BF.