大豆抗原蛋白对断奶仔猪细胞因子及肠上皮紧密连接蛋白Claudin-1 mRNA表达的影响

Effects of soybean antigen protein on cytokines and the mRNA expression of tight junction protein Claudin-1 in intestinal epithelium of weaning piglets

选取70头24日龄"杜×长×大"断奶仔猪,随机分成7组,每组10头仔猪。对照组(A组)饲喂基础日粮,β-伴大豆球蛋白(β-Conglycinin,7S)(B、C、D组)和大豆球蛋白(Glycinin,11S)试验组(E、F、G组)分别添加500、2 000、5 000μg/kg质量的7S或11S。仔猪断奶时开始饲喂大豆抗原蛋白,分别于24、26、28、30日龄采集血液,测量血清中细胞因子含量。于试验结束时,每组选取5头仔猪放血致死,采集小肠各段,实时荧光定量PCR(qRT-PCR)法检测小肠各段Claudin-1mRNA的相对表达量。结果显示,与对照组相比,随着7S和11S剂量的增加,血清中IL-2、IL-4、IL-6的含量升高,血清中INF-γ的含量降低。与对照组相比,7S与11S试验组中的D、G组各肠段Claudin-1mRNA的相对表达量均显著降低(P<0.01),C组的空肠前段、空肠中段和空肠后段均显著降低(P<0.01)。与7S试验组相比,除11SB、C组的回肠显著降低,其余各组均显著升高。试验表明,7S和11S均能够通过影响细胞因子的含量,引起断奶仔猪的体液和细胞免疫反应,降低断奶仔猪十二指肠和空肠Claudin-1mRNA相对表达量,引起仔猪肠道黏膜损伤,且7S比11S对仔猪的损伤程度更大。

Seventy ＂Duroc×Landrace× Yorkshire＂ crossbred piglets were chosen and randomly di- vided into seven groups of 10 piglets each. Piglets were fed with basic diet in control group （group A）,add 500,2 000,5 000 μg/kg · W β-conglycinin （7S） in groups B,C,D or glycinin （11S） in groups E,F,G,respectively. Blood samples were collected at days 24,26,28 and 30 for measuring serum cytokines （IL-2, IL-4, IL-6,IL-8 and INF-γ）. At the end of the trial, five piglets in each group were slaughtered and segments of the small intestine were collected for determining Clau- din-1 mRNA relative expression levels by real-time quantitative PCR （qRT-PCR）. The results showed that, compared with the control group, the levels Of serum IL-2, IL-4, IL-6 were increased, while the levels of serum INF-γ were decreased with the increased 7S and 11S. The relative expres- sion of Claudin-1 mRNA were reduced（P〈0.01）in segments of groups D,G and decreased（P〈 0.01） in proximal jejunum, middle jejunum and distal jejunum of group D. Compared with 7S group,except the decreased mRNA expression levels in ileum of groups B and C, relative mRNA expression were increased in 11S group. These results suggest that 7S and 11S lead to humoral and cellular immune responses by influencing the content of cytokines and cause damage of intestinal mu- cosal via reducing the relative expression of Claudin-1 mRNA in duodenum and jejunum of piglets.Furthermore,the damage to intestinal epithelium caused by 7S is more serious than that 11S.