猪β-防御素-2在黄曲霉毒素B1致小鼠肠道炎症损伤中的作用

Effect of porcineβ-defensin-2 on intestinal inflammatory injury induced by aflatoxins B1 in mice

旨在探究猪β-防御素-2(pBD-2)在黄曲霉毒素B1(AFB1)致鼠肠道损伤中的作用。本试验以4周龄KM小鼠为研究对象,将体重相近的30只健康小鼠随机均分为5组,分别为空白对照组(不做任何处理)、DMSO组(1%DMSO灌胃)、AFB1组(0.3 mg/kg AFB1灌胃)、pBD-2组(0.03 mg/kg pBD-2灌胃)和AFB1+pBD-2组(0.3 mg/kg AFB1灌胃28 d后再用0.03 mg/kg pBD-2灌胃28 d),试验持续56 d,通过观察小鼠肠道结构的变化以及采用qPCR和免疫荧光的方法检测炎症相关因子的表达水平。结果:与对照组相比,AFB1组小鼠的平均日增重(ADG)和平均日采食量(ADFI)均呈现显著下降趋势(P<0.05),料重比(F/G)降低,但差异不显著(P>0.05),而小鼠饲喂pBD-2以后ADG和ADFI均较AFB1组显著增加(P<0.05);HE染色结果显示,AFB1导致小鼠空肠黏膜显著损伤,并伴有严重的肠壁变薄,肠绒毛萎缩、稀疏,肠绒毛高度与隐窝深度之比、相对肠绒毛数量及肠壁厚度均显著降低(P<0.05),而使用pBD-2处理小鼠损伤模型,肠道结构可见显著恢复(P<0.05);qPCR和免疫荧光染色结果表明,AFB1处理小鼠可显著上调白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)的mRNA和蛋白表达水平(P<0.05),但对白细胞介素-8(IL-8)的表达水平出现了下调趋势,而用pBD-2处理小鼠损伤模型后可显著下调炎症因子的表达水平,说明pBD-2对AFB1造成的肠黏膜炎症具有缓解作用。本研究结果为AFB1中毒的防控及pBD-2在畜牧生产中的应用提供了科学依据。

The aim of this experiment was to investigate the effect of porcineβ-defensin 2(pBD-2)on intestinal injury induced by Aflatoxin B1(AFB1)in mice.The experiment took 30 healthy 4-week-old KM mice with similar body weight as the subjects which were randomly divided into 5 groups,including the control group(no treatment),the DMSO group(treated with 1%DMSO),the AFB1 group(with 0.3 mg/kg AFB1),the pBD-2 group(the 0.03 mg/kg pBD-2)and the AFB1+pBD-2 group(with 0.3 mg/kg AFB1 for 28 days followed by 0.03 mg/kg pBD-2 for 28 days).The experiment lasted for 56 days,when the changes in the intestinal structure of the mice were observed and the expression of inflammation-related factors in them were detected by qPCR and immunofluorescence.The results showed that,compared with the control group,the average daily gain(ADG)and the average daily feed intake(ADFI)of the mice in the AFB1 group showed a significant downward trend(P<0.05),and their ratio of feed to gain(F/G)was decreased,but not significantly different from that of the control group,while their ADG and ADFI were significantly increased after feeding with pBD-2,as compared with those of the AFB1 group(P<0.05).The HE staining results showed that AFB1 caused significant injury of jejunum mucosa in the mice,accompanied by severe intestinal wall thinning,intestinal villi atrophy and thinning.The ratio of villi height to crypt depth,the relative villi number and intestinal wall thickness in the rodents were significantly reduced by AFB1(P<0.05),and their intestinal structure was significantly recovered(P<0.05).The results of the qPCR and immunofluorescence staining showed that the AFB1 treated mice significantly up-regulated their mRNA and protein expressions of interleukin-1β(IL-1β),interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α)(P<0.05),but down-regulated the expression of interleukin-8(IL-8)in them;while the pBD-2 treated mice injured models significantly down-regulated the expression of inflammatory factors in them.The above results indicated that pBD-2 had an alleviating effect on intestinal mucosal inflammation caused by AFB1,which provided scientific basis for the prevention and control of AFB1 poisoning and the application of pBD-2 in livestock production.