The Signal Transduction Mechanism Of Intestinal Allergic Damage Induced By Soybean Antigen Protein In Piglets

In this experiment,the weaned piglets were fed the diet with ?-conglycinin or glycinin,and the objective of this study was to investigate the effects of soybean antigen proteins on the form of small intestine villus,the integrity of organelle and the intestinal function in piglets,and to study the signal pathways of inflammatory damage and apoptosis in allergic piglets induced by?-conglycinin or glycinin.Forty healthy “Duroc×Landrace×Yokshire” piglets(20 day of age)were selected and randomly divided into four groups,ten piglets in each group.Besides sucking group,the piglets in weaned group were fed a basal diet at age of 21 days,and the piglets in soybean antigen protein groups were fed a basal diet supplemented with ?-conglycinin or glycinin.The trial period was seven days.At the age of 20 and 27 days,blood samples were collected from the anterior cavity vein,plasma and serum were separated from the blood,then diamine oxidase,caspase-3,NO,5-hydroxylamine,d-lactic acid and tumor necrosis factor-? levels were measured by ELISA.At the age of 27 day,five piglets per group were sacrificed and their intestinal sections were removed,the duodenum,jejunum and ileum were divided into several parts and kept in paraformaldehyde,glutaraldehyde and liquid nitrogen.The tissues in stationary liquid were used to measure the expression of NF-?B,JNK,p38 in intestine by immunohistochemistry and to observe the form of small intestine villus by electron microscope.The tissues in liquid nitrogen were used to measure the relative expression of NF-?B,jnk,p38 mRNA by qRT-PCR.The results showed that:1.The villus of piglets in sucking group were intact and defect in weaned group,different degrees of structural damage and cell necrosis of villus in jejunum were occurred in the soybean antigen protein groups by scanning electron microscope.2.At 27 d,compared with the weaned group,the plasma D-LA,DAO,5-HT levels were decreased in sucking group(P>0.05),especially the D-LA levels(P<0.05).The plasma D-LA,5-HT,DAO levels were significantly increased(P<0.01)in soybean antigen protein groups.The plasma D-LA levels in glycinin group were higher than those in ?-conglycinin group(P<0.05).3.At 27 d,the serum NO,TNF-? levels in soybean antigen protein groups were significantly higher(P<0.01)than those in weaned group.The serum NO levels in glycinin group were higher than those in ?-conglycinin group(P<0.05).But there was no significant difference between sucking group and weaned group(P>0.05).The serum casp-3 levels were significantly increased in glycinin group(P<0.01).The serum casp-3 levels in ?-conglycinin group were higher than those in weaned group(P<0.01)and glycinin group(P<0.05),and the serum asp-3 levels in sucking group were lower than those in weaned group(P>0.05).4.Compared with the weaned group,the relative expression of NF-?B mRNA in duodenum and jejunum were no significant difference between sucking group and weaned group(P>0.05),but were significantly increased in soybean antigen protein groups(P<0.01).The relative expression of NF-?B mRNA in ileum were decreased in sucking group(P<0.05),and were significantly increased in soybean antigen groups(P<0.01),and the relative expression of NF-?B mRNA in glycinin group were higher than those in ?-conglycinin group(P<0.05).A similar trend was found in the expression of NF-?B.5.Compared with the weaned group,the relative expression of JNK mRNA in duodenum were decreased in sucking group(P<0.05),were significantly increased in soybean antigen protein groups(P<0.01)and the relative expression of JNK mRNA in glycinin group were higher than those in ?-conglycinin group(P<0.01).The relative expression of JNK mRNA in jejunum were no significant difference between sucking group and weaned group(P>0.05),but significantly increased in soybean antigen protein groups(P<0.01).The relative expression of JNK mRNA in ileum were decreased in sucking group(P>0.05),and were increased in soybean antigen protein groups(P<0.01),and the relative expression of JNK mRNA in ?-conglycinin group were higher than those in glycinin group(P<0.01).A similar trend was found in the expression of JNK.6.Compared with the weaned group,the relative expression of p38 mRNA in duodenum were decreased in sucking group(P<0.05)and were significantly increased in soybean antigen protein groups(P<0.01).The relative expression of p38 mRNA in jejunum were decreased in sucking group(P<0.05)and were significantly increased in soybean antigen protein groups(P<0.01),and the relative expression of p38 mRNA in glycinin group were higher than those in?-conglycinin group(P<0.05).The relative expression of p38 mRNA in ileum were no significant difference between sucking group and weaned group(P>0.05)and were significantly increased in soybean antigen protein groups(P<0.01),and the relative expression of p38 mRNA in?-conglycinin group were higher than those in glycinin group(P<0.05).A similar trend was found in the expression of p38.The results showed that ?-conglycinin and glycinin could damage the integrity of intestinal villus and cell structure,and cause the damage of intestinal function in piglets.Meanwhile,?-conglycinin and glycinin could increase the expression of NF-?B,JNK,p38 and mRNA,regulate inflammation and apoptosis pathways by stimulating the expression of inflammatory factors,increase the inflammatory reaction and cause apoptosis finally.