CpG-DNA对大肠杆菌诱导的大鼠实验性乳腺炎的影响  

Effect of CpG-DNA on Mastitis Induced by Escherichia coli Infection in Rat Model

作　　者：朱于敏[1] 马海田[1] 陈伟华[1] 邹思湘[1] 

机构地区：[1]南京农业大学农业部动物生理生化重点开放实验室,南京210095

出　　处：《农业生物技术学报》2006年第5期706-710,I0003,共6页Journal of Agricultural Biotechnology

基　　金：国家自然科学基金项目(No.30371049)资助

摘　　要：72只雌性大鼠随机分成对照组和实验组(n=36)。对照组产后0h于左后腿胫骨前肌肌肉注射0.01mol/L,pH7.2磷酸盐缓冲液(PBS)100μL,实验组肌注CpG-DNA200μg/只,72h后经乳头管灌注2×1012cfu(colonyformingunit/mL)/mL,大肠杆菌(Escherichiacoli)100μL/侧到第4对(两侧)乳腺内,分别于灌注前0h,灌注后8,16,24,48和72h(n=6)颈静脉放血处死。组织学观察显示大鼠感染后16h为乳腺腺泡嗜中性粒细胞(polymorphonuclearleukocytes,PMN)浸润高峰,实验组PMN浸润迅速,72h已无浸润。乳腺组织细菌数在16h上升至最高,实验组大鼠感染后16、24和48h乳腺组织细菌数较对照组有显著下降。CpG-DNA能极显著地提高感染前乳腺组织中IL-2水平。乳腺组织IL-6在不同时间点均有显著上升,在16h达最高。CpG-DNA能显著地提高16h乳腺组织IL-6水平。实验组乳腺组织N-acetyl-β-D-glucosaminidase(NAGase)无显著变化。表明CpG-DNA可加速炎症初期PMN的快速浸润,促进IL-2和IL-6的产生,减少细菌数量,减轻炎症介质对细胞的损伤并缩短炎症过程,提示CpG-DNA对大肠杆菌诱发的大鼠实验性乳腺炎有一定的预防作用。Seventy-two lactating SD rats were randomly divided into control and treatment groups （n =36）. The 100 μL of sterile 0.01 mol/L ,pH 7.2 PBS（phosphate-buffered saline）（control group） and CpG 200 μg/rat（treatment group） were injected intramuscularly into tibialis anterior of the left leg after parturition 0 h respectively. Then 100μL/rat of bacterial suspension containing 2× 10^12 cfu （colony forming unit）/mL（both sides） of Escherichia coli were inoculated into the fourth （abdominal） manunary gland via the teat duct 72 h after parturition respectively. Before defined at o h and after 8,16,24,48 and 72 h （n =6） of inoculation, all the rats euthanatized and the mammary glands and serum were harvested. The histopathologic evaluations showed that polymorphonuclear leukocytes （PMN） accumulation in alveoli peaked 16 h postinfection. The PMN in treatment group influxed more rapidly and no PMN was found in alveoli 72 h after infection. Bacteria counts of E. coli in mammary gland peaked at 16 h postinfection and CpG-DNA induced significant decrease of viable bacteria at 16, 24 and 48 h postinfection. CpG-DNA induced significant increase of IL-2 in manunary gland before infection. Significant increases in IL-6 and TNF-α in mammary gland were observed at different time points in both group. The maximal increases in IL-6 were at 16 h postinfection, the time that was coincident with peak infiltration ofPMN. CpG-DNA could induced significant increase of IL-6 in mammary gland at 16 h postinfection. No significant changes ofN-acetyl-β -D-glucosaminidase （NAGase） in mammary gland from treatment group were observed. The result showed that CpG-DNA induced more prompt migration of PMN from blood to manunary gland at the initial stage of E. coli infection, stimulated the secretion of IL-2 and IL-6, decreased E. coli counts in mammary gland and attenuated the destroy of inflammation-mediator to cell. The study indicates that CPG DNA protects against mastitis at some extent induced by E. coli

关 键 词：CPG-DNA 乳腺炎 大鼠 大肠杆菌 

分 类 号：S188[农业科学—农业基础科学]