The Influence Of Rat Intestinal Bilogical Barriers To Sensitization Effect Of Ovalbumin

ObjectiveThe purposes of this study are to explore the influence of intestinal flora to the sensitization effect of Ovalbumin, to investigate the relationship between intestinal disorder and allergic reaction, and to study the roles of Bifidobacterium in the prevention and treatment of food allergy.MethodsBrown Norway rat sensitized animal model was constructed, BN rats were fed with 1 mg Ovalbumin every day for six weeks. At the same time, PBS group, OVA group, Kanamycin group, Bifidobacterium prevention group, and Bifidobacterium treatment group were established. OVA specificity IgE levels and OVA specificity IgG levels of serum were detected every week. The IgE level of PBS group was taken as allergic judgment standard. At the same time, dung of BN rats was gathered every week by using metabolic cage for testing their gut flora amount and for testing the mRNA expression level of Bifidobacterium, Lactobacillus, Escherichia coli and Staphylococcus aureus. In the sixth week, rats were executed and tissues of the next segment of Ileum were obtained to observe morphological structure by using Optical microscope and Electronic microscope, and to test the number of CD4+T cell and CD8+T cell by using immunohistochemistry protocol.Results1. The sensitized situationAfter the end of experiment, each of the OVA group and Kanamycin group each had four sensitized rats, the rate of sensitization was 57%. Each of the Bifidobacterium prevention group and Bifidobacterium treatment group each had one sensitized rats, the rate of sensitization was 14%.2. The result of OVA specificity IgG level The result of analysis of variance about repeated measurement data showed that there were interaction between factor and time. In the second week, IgG level of the PBS group and Bifidobacterium prevention group were lower than that of OVA group (all, P<0.05). In the forth week, IgG level of PBS group and Bifidobacterium prevention group were still lower than that of OVA group (all, P<0.05). IgG level of the Kanamycin group was different from that of OVA group and Bifidobacterium treatment group respectively (all, P<0.05). In the sixth week, IgG level of PBS group and Bifidobacterium prevention group were different from that of OVA group (all, P<0.05). There were differences between IgG level of Kanamycin group and Bifidobacterium treatment group (P<0.05).3. The results of immunohistochemistry of CD4+T cell and CD8+T cellThe results show that, the quantity of CD4+T cell and CD8+T cell of PBS group was more than that of the other groups, the quantity of CD4+T cell and CD8+T cell of Bifidobacterium prevention group and Bifidobacterium treatment group was more than that of OVA group and Kanamycin group.4. The result of total bacterial count in fecesThe result of analysis of variance about repeated measurement data showed that there were interaction between factor and time. The total bacterial counts of PBS group and OVA group were different from that of Kanamycin group respectively in the first week (all, P<0.05). The total bacterial count of OVA group was different from that of Bifidobacterium prevention group (P<0.05). The total bacterial count of PBS group was different from that of the other four groups in the second week (all, P<0.05). There were no differences between every group in the third week. The total bacterial counts of PBS group and OVA group were different from that of Kanamycin group in the forth week (all, P<0.05). The total bacterial count of PBS group was different from that of Bifidobacterium prevention group in the fifth week (P<0.05). The total bacterial count of PBS group and OVA group were different from that of Bifidobacterium prevention group respectively in the sixth week (all, P<0.05).5. The result of Relative fluorescence quantitative polymerase chain reaction (PCR) of Bifidobacterium, Lactobacillus, Escherichia coli and Staphylococcus aureus The results show that the Bifidobacterium could inhibit the mRNA expression level of Escherichia coli and Staphylococcus aureus, and could improve the mRNA expression level of Bifidobacterium and Lactobacillus.6. The results of HE dyed on the next segment of HeumResults show that intestinal villi of PBS group and Bifidobacterium prevention group were complete, there were no intestinal epithelium cell damaged and inflammatory infiltration, and the intestinal villi of Bifidobacterium treatment group were complete too. Only few epithelial cells of intestinal mucosa were with oedema occasionally. However, in OVA group and Kanamycin group, intestinal villus were defected, and intestinal villus epithelial cells had focal necrosis, and intestinal villus were dropsical, and inflammatory cells infiltrated obviously.7. The results of electronic microscope show that intestinal villus of PBS group and Bifidobacterium prevention group were complete, but the intestinal villus of OVA group defected. The closely connected structure of PBS group was intact, but it was expanded obviously in OVA group and was incompact in Bifidobacterium prevention group.Conclusions1. Intestinal flora disorder already existed before food allergy happened.2. Bifidobacterium could be used to prevent and treat food allergic diseases.3. OVA could lead the number of CD4+T cell and CD8+T cell to reduce, and could influence the number of intestinal flora.