| With the rapid development of genetically modified (GM) crops, a number of fundamental issues regarding health concerns have been raised by the general public. The potential allergenicity of GM foods is one of the issues. Recently, the development of animal models to be used for the assessment of allergenicity in GM crops has become an area of intense research and development. The judicious use of an accurate and robust animal model could provide important additional data that would contribute significantly to the assessment of the potential allergenicity of novel proteins. Brown Norway (BN) rat model was further improved, and C3H/HeJ mice model was initially discussed in this study.1. BN rat model was further improvedObjective: To study the proper sex and age of BN rat and find out the appropriate period of sensititation and dose of allergen by the orally route of exposure. Methods: Three doses (10.0mg/d, 1.0mg/d, and 0.1mg/d) of allergenic protein ovalbumin (OVA) were administered orally to BN rats of different sex and age for 35 days. Blood samples were taken on the 28th and 35th days from the orbital plexus and sera were obtained to determine OVA specific IgE (OVA sIgE). Spleen, thymus, jejunum and mesenteric lymph nodes samples were obtained on the 35th day to have the histopathology test. Results: (1) Compared with the control group, the concentrations of OVA sIgE of 4-week and 8-week femal BN rats on the 28th and 35th days were significantly increased when 1.0mg/d OVA was applied (P<0.05). There were no significant differences of the concentrations of OVA sIgE of 4-week and 8-week female BN rats on the 28th and 35th days when 10.0mg/d OVA was applied compared with the control group. (2) The concentration of OVA sIgE on the 28th and 35th days of all groups of 4-week male BN rats showed no significant differences. (3) The concentrations of OVA sIgE of 8-week male BN rats on the 28th day were significantly higher than the control group when 0.1mg/d OVA was applied (P<0.05), but the concentration of OVA sIgE on the 28th and 35th days of other groups of 8-week male BN rats showed no significant differences. (4) Some eosinophils were observed on the mucosal lamina propria of both control groups'and test groups'jejunum. Conclusion: Allergenic protein ovalbumin (OVA) was administered orally to BN rat, (1) Female BN rats were more sensitive to OVA than male BN rats; (2) there was no difference between 4-week and 8-week BN rats; (3) the most sensitive dose of OVA is 1.0mg/d by orally exposure; (4) the appropriate period is 28-35 days for the route of oral gavage.2. C3H/HeJ mice was discussed initiallyObjective: To study the feasibility of C3H/HeJ mice as the food allergenicity rodent model and explore the appropriate period of two different routes of exposure and the change of helper T lymphocyte cell. Methods: Allergenic protein ovalbumin (OVA) was administered intraperitoneally or orally to female C3H/HeJ mice for 35days. Blood samples were taken on the 14th, 28th and 35th days from the orbital plexus and sera were obtained to determine OVA specific IgE (OVA sIgE). Spleen samples were obtained on the 35th day to detect the mRNA expression of Th2-type cytokines IL-4 and Th1-type cytokines IFN-γby real-time RT-PCR. Results: Compared with the control group, the concentration of OVA sIgE on 28th and 35th days were significantly increased in OVA group by gavage (P<0.05). The concentration of OVA sIgE on 14th, 28th and 35th days were significantly higher than the control group when OVA was given intraperitoneally (P<0.05). Compared with the control group, the mRNA expression of IL-4 of OVA group and OVA+Al (OH)3 group were significantly increased. The mRNA expression of IFN-γof OVA group and OVA+ Al (OH)3 group were significantly lower than the control group. Conclusion: C3H/HeJ mice might be used as a rodent model for the assessment of allergenicity of food. The appropriate period is the 14th day for the route of intraperitoneal injection and the 28th day for oral gavage, respectively.
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