Abstract:

Objective: To observe the changes of polyunsaturated fatty acid metabolism in Balb/C mice model of ovalbumin(OVA)induced allergy. Methods: At 21 day old, 24 baby Balb/C mice, whoes mother had a diet of n-3PUFA deficiency, randomly divided into 3 groups, blank, OVA and PBS groups. There were 8 offsprings in each group. Weaned BALB/c offsprings in group h, m and l were sensitized with 50 μg of OVA (grade V, Sigma) in the presence of 1.3 mg of aluminum hydroxide gel (Sigma) as an adjuvant by intraperitoneal injection twice at 3 and 5 weeks old. Half of the offsprings delivered from the mice of the control group were sensitized with OVA as positive control. And remainders of the offsprings were injected with PBS as negative control.The sensitized BALB/c mice with 7 weeks of life were fed with 50 mg of OVA dissolved in 0.3 mL of sterile saline by intragastric needles at interval day for six times. One hour after the last oral administration, all BALB/c mice were sacrificed with excessive carbon dioxide and blood samples were collected by cardiac puncture.At the first day of the test, blood samples of baby mice in blank group were collected by cardiac puncture. The offsprings in group OVA were sensitized with 50 g of OVA dissolved in 0.2 mL PBS in the presence of 1.3 mg of aluminum hydroxide gel by intraperitoneal injection at 1 and 15 day. From 29 to 39 day, the offsprings in OVA group were fed wiht 50 mg of OVA dissolved in 0.3 mL of PBS by intragastric needles at interval day for six times. The offsprings in PBS group were given equivalent PBS. After the last oral administration, all BALB/c mice were sacrificed by cardiac puncture and blood, jejunum, spleen samples were collected. To establish the model of OVA-induced allergy, diarrhea was observed after OVA challenge; histological examinations of jejunum were performed by HE staining and the mast cells in jejunum were observed by toluidine blue staining; and the levels of OVAsIgE in serum, IL-4 and IFN-γ in spleen cell culture supernatants were measured by ELISA. Fatty acids were extracted from serum in each group. The linoleic acid (ALA), inolenic acid (LA), arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexenoic acid (DHA) levels of serum were analyzed by high performance liquid chromatography.Results：①The model of OVA-induced allergy in Balb/C mice was established: compared with group PBS, after the oral OVA challenge allergic diarrhea, gathered phenomenon of inflammatory cells in jejunum villus，aggregation of mast cells in lamina propria（P＜0.05），increasing of the levels of OVA-specific IgE in serum and IL-4, IL-4/IFN-γ in spleen cells(P＜0.05) were observed in the offspring of OVA group. ②The levels of DHA, EPA and LA of mice in group PBS were statistically lower than those in blank group. Compared with PBS group, the levels of DHA decreased in mice of OVA group.Conclusion：Balb/C mice，repeatedly exposed with OVA, exerted a fatty acid metabolic disorder, mainly a reduction of DHA.