异食癖对哺乳期犊牛肠道黏膜通透性及免疫因子表达的影响

Effects of Pica on Intestinal Mucosal Permeability and Immune Factor Expression in Suckling Calves

为研究异食癖对哺乳期犊牛肠道通透性及免疫因子表达的影响,选择出生3周左右,体重相近的犊牛(54.7±5.83 kg)作为研究对象,根据犊牛舔食牛毛、沙子等行为,随机选择12头表现为被毛粗乱、消瘦、腹泻和发育受阻等症状的犊牛为异食癖组,健康、无食牛毛、沙子等症状的12头犊牛作为对照组。至犊牛断奶(56 d),每组随机选择5头进行屠宰,取十二指肠组织,利用Real-time PCR技术分析犊牛肠道紧密连接蛋白-1(ZO-1)、咬合蛋白(Occludin)、闭合蛋白(Claudin)、Toll样受体4(TLR4)、肿瘤坏死因子-α(TNF-α)和白细胞介素1(IL-1β)的m RNA在肠道黏膜上的表达水平变化。结果表明,异食癖犊牛肠黏膜蛋白ZO-1相对表达量显著低于对照组犊牛(P<0.05),Occludin和Claudin相对表达量低于对照组,但差异不显著(P>0.05),异食癖犊牛肠道黏膜通透性增加,免疫因子TLR4相对表达量显著低于对照组(P<0.05),TNF-α和IL-1β相对表达量极显著高于对照组(P<0.01),异食癖犊牛肠道免疫因子表达下调,肠道黏膜炎症因子表达上调,肠道抗氧化能力减弱。

The experiment was aim to study the effects of pica on intestinal permeability and immune factor expression in suckling calves.The 243-week calves with similar weight(54.7±5.83 kg)were assigned in two groups according to whether the calves had pica in terms of the behaviors like eating hairs or sand.The 12 calves suffering from pica with symptoms like coarse hair,losing weight,emaciation,diarrhea or dysplasia were randomly selected into the pica group.The 12 calves in good condition,not eating hair,sand and other foreign substances were randomly selected into the control group.5 calves were randomly selected from each group to be slaughtered after weaning(about56-day-old).?Duodenum were taken as samples.Then the mRNA expression of ZO-1,Occludin,Claudin,TLR4,TNF-αand IL-1βin the intestinal tract of the calves were analyzed based on real-time PCR technique.The results showed that,compared that in the control group,the relative expression of intestinal mucosal protein ZO-1 in pica group was significantly lower(P<0.05)and that of Occludin and Claudin was lower,but the difference was not significant(P>0.05).It indicated that the intestinal mucosal permeability of pica calves might increase.The relative expression of intestinal immune factor TLR4 in pica group was significantly lower(P<0.05)compared to that in control group,and the that of TNF-αand IL-1βwas significantly higher(P<0.01).In conclusion,the expression of intestinal immune factors in pica group decreased,while the expression of inflammatory factors in intestinal mucosa increased,indicating the antioxidant capacity of intestinal tract might be weakened.