盐酸小檗碱对E.coli诱导的断乳仔兔腹泻转录因子NF-κB信号通路的影响

Effect of berberine hydrochloride on NF-κB expression in diarrhea of weanling rabbit induced by E.coli

为探讨盐酸小檗碱（BBR）在仔兔大肠杆菌性腹泻中的作用及其对NF-KB信号通路的影响，试验选取120只30日龄新西兰兔，接种大肠杆菌待出现腹泻症状后随机分为4组，每组30只。第1组为BBR低剂量治疗组（0．1gjkg），第2组为BBR中剂量治疗组组（0．2g／kg），第3组为BBR高剂量治疗组（0．3g／kg），第4组为不用药感染组，另取10只健康仔兔作为正常对照组，治疗组按各剂量连续口服给药5d。每天定时测体质量，观察临床症状，统计有效率、治愈率、死亡率作为评价指标。用qRT—PCR和Westernblot方法分别检测肠道组织内NF—KBp65基因及蛋白表达量。结果显示，感染组仔免出现精神沉郁、食欲减退或废绝及腹泻等临床症状，且体质量下降明显；与感染组相比，治疗组仔免死亡率明显降低（P〈0．05）；随着用药剂量增加仔兔肠道组织内NF-KBmRNA及其蛋白表达极显著减弱（P〈0．01）。结果表明，NF—KB信号通路参与了大肠杆菌感染诱导仔兔腹泻导致肠损伤过程，而BBR可下调NF—KBmRNA和蛋白的表达，在治疗大肠杆菌导致肠损伤方面具有广泛的应用前景。

To observe the effect of berberine hydrochloride（BBR） on NF-κB expression in intestinal mucosa of diarrhea induced by Escherichia coli （E. cold infection in weanling rabbit. A total of 120 30-day SPF New Zealand rabbits were inoculated with bacterial fluid of E. coli（0. 1 mL a rabbit）, after making the diarrhea model, then randomized into four groups：low-dose BBR group （0. 1 g/ kg） ,medium-dose BBR group（0.2 g/kg）,high-dose BBR group（0.3 g/kg）,infection group with- out BBR,another 10-day healthy rabbits as normal control group. The clinical signs and（body） weight of rabbits after infection and treatment were observed and the effective percentage, the cure rate and the mortality were recorded in each group. The mRNA and protein expression of NF-κB in the intestinal tissue were observed at 2,4,6,8,10,12 and 14 days after treatment by qRT-PCR and Western blot methods. The results showed that Escherichia coli-infected rabbits presented depres- sion,loss of appetite or waste,diarrhea and weight loss dramatically（P〈0.05）. Compare to that of Escherichia coli-infected rabbits,the BBR treatment alleviated clinical signs and decreased mortali- ty（P〈0.05）. BBR treatment also markedly down-regulated the levels of mRNA and protein of NF-κB in the intestinal tissue of Escherichia coli-infected rabbits（P〈0.01）. These data demon strated that NF-κB signaling pathway participated in diarrhea stress intestinal tissue injury induced by Escherichia coli-infected in rabbit and BBR down-regulated remarkably the levels of mRNA and protein of NF-κB during bacterial infection, thus supporting the use of BBR for managing diar- rhea cases of the weaned rabbit.