Hadria Grar

Allergenic changes in β-lactoglobulin induced by microwave irradiation under different pH conditions

Abstract The allergenicity of β-lactoglobulin (BLG) was assayed by Ussing chamber after microwave irradiation of whey proteins at different pH values, in a murine model of BLG allergy. BALB/c mice were sensitised intraperitoneally with BLG. Serum levels of BLG-specific IgG, IgG1, IgG2a and IgE were analysed by Enzyme-Linked Immunosorbent Assay (ELISA). Local anaphylactic responses and residual allergenicity of various treated whey proteins were performed in vitro in Ussing chamber. BLG immunisation was associated with strong IgG, IgG1, IgG2a and IgE production, a significant increase in short current circuit (Isc) and high conductance (G) response. The allergenic potential of BLG was markedly reduced after microwave irradiation at 300 or 700 W of whey proteins at pH values 6.8 or 4.6 (Isc and G remained unchanged after intestine challenge with treated whey proteins). The application of microwave irradiation of whey proteins at the natural milk pH (pH 6.8) or pH 4.6 induces a significant decrease in the BLG allergenicity.

Preventive effects of royal jelly against anaphylactic response in a murine model of cow’s milk allergy

Abstract Context: Royal jelly (RJ) has long been used to promote human health. Objective: The current study investigated the preventive effects of RJ against the development of a systemic and intestinal immune response in mice allergic to cow’s milk proteins. Materials and methods: Balb/c mice treated orally for seven days with RJ at doses of 0.5, 1 and 1.5 g/kg were sensitized intraperitoneally with β-lactoglobulin (β-Lg). Serum IgG and IgE anti-β-Lg were determined by an enzyme-linked immunosorbent assay (ELISA). Plasma histamine levels, symptom scores and body temperature were determined after in vivo challenge to β-Lg. Jejunums were used for assessment of local anaphylactic responses by an ex vivo study in Ussing chambers and morphologic changes by histological analysis. Results: RJ significantly decreased serum IgG (31.15–43.78%) and IgE (64.28–66.6%) anti-β-Lg and effectively reduced plasma histamine level (66.62–67.36%) (p < 0.001) at all the doses tested. Additionally, no clinical symptoms or body temperature drops were observed in RJ-pretreated mice. Interestingly, RJ significantly reduced (p < 0.001) intestinal dysfunction by abolishing the secretory response (70.73–72.23%) induced by sensitization and prevented length aberrations of jejunal villi by 44.32–59.01% (p < 0.001). Discussion and conclusions: We speculate that using RJ may help prevent systemic and anaphylactic response in allergic mice. These effects may be related to its inhibitory effects on the degranulation of mast cells.

Effect of a normal protein diet on oxidative stress and organ damage in malnourished rats

BackgroundWe investigated the effects of three weeks of renutrition with a normal protein diet on oxidant/antioxidant status in malnourished rats using biochemistry and histology.MethodsEighteen young Wistar rats were divided into three groups: control group was fed on a normal protein diet; malnourished group was fed on low protein diet and renourished group was fed on low protein diet followed by a normal protein diet. Serum albumin was evaluated. Malondialdehyde, protein carbonyl, superoxide dismutase and catalase levels were determined in the intestine, muscle and liver. Intestinal and hepatic damage were assessed by histological examination.ResultsProtein malnutrition resulted in a significant decrease of body weight, albumin level, villus length, intraepithelial lymphocytes counts (IELC) and superoxide dismutase level (liver and muscle). However, catalase activity increased significantly in muscle and gut but there was no difference in liver. In all organs, malondialdehyde and protein carbonyl content of malnourished group showed a significant increase. Interestingly, a normal protein diet for three weeks resulted in a return to normal levels of superoxide dismutase, albumin, malondialdehyde and protein carbonyl in all organs. Catalase activity decreased in the muscle and gut and exhibited no significant difference in the liver. The renutrition diet enhanced also the recovery of intestinal epithelium by increasing villus length. Hepatic damage of rats fed normal protein diet was markedly reduced (macrovesicular steatosis decreased by 45%).ConclusionThe normal protein diet could improve the oxidant/antioxidant imbalance and organ damage induced by protein malnutrition.

Bovine lactoferrin allergenicity as studied in murine model of allergy

ABSTRACT In our study, we tried to investigate the allergenic properties of bovine lactoferrin (bLf) at different doses. The lactoferrin (LF) allergenicity was explored using murine model of allergy through measuring anti-LF IgG, IgG1 and IgE antibodies (Abs) responses and by in vivo anaphylactic reactions in LF sensitized mice. A histological examination of intestinal lamina propria was performed to assess gut inflammation. Four groups of mice (Balb/c) were sensitized intraperitoneally to bLf using different doses (1%, 2%, 5% and 10%). Histological study of intestinal lamina propria revealed a marked decrease in villus length in 5% and 10% sensitized mice groups. Also, high levels of anti-bLf IgG and IgE were observed. Concerning the in vivo reactions, all groups developed clinical symptoms of anaphylactic reactions at different stages. Our findings show that LF-sensitized mice at 5% and 10% developed important clinical symptoms after intraperitoneal challenge with LF. GRAPHICAL ABSTRACT