The effects of lipoic acid on soybean beta-conglycinin-induced anaphylactic reactions in a rat model

The purpose of this study was to evaluate the effects of feeding a low dose of lipoic acid on attenuating soybean beta-conglycinin-induced hypersensitivity using a rat model, with ovalbumin as the positive allergic control. Forty-eight recently weaned male Sprague-Dawley rats were assigned to four treatments and fed a cornstarch-casein-based diet either unsupplemented (Groups I, II and III) or supplemented with 25 mg/kg lipoic acid (Group IV). On days 1, 10, 17, and 24, Groups III and IV were sensitised with 20 mg beta-conglycinin by means of intragastric gavage, while Group II was sensitised with 20 mg ovalbumin and Group I (control) with casein. On day 31, rats received a double dose of beta-conglycinin, ovalbumin or casein, respectively. Ovalbumin-sensitised rats (Group II) and beta-conglycinin-sensitised rats (Group III) demonstrated an increase in serum IgE and histamine release, but reduced growth performance compared to the control (Group 1) (p < 0.05). A low dose of lipoic acid had no effect on average weight gain, but increased villus height in the jejunum (p < 0.05), while reducing serum beta-conglycinin-specific IgE and histamine content in the jejunum. Moreover, lipoic acid supplementation did not significantly affect interferon-gamma or interleukin-4. Taken together, our results suggest that a low dose of lipoic acid could potentially be used as an immunomodulator to attenuate soybean beta-conglycinin induced allergies.