ZINC AND INTESTINAL ANAPHYLAXIS TO COWS MILK-PROTEINS IN MALNOURISHEDGUINEA-PIGS

Zinc supplementation could favor recovery from diarrhea in malnourishe d children. As the recent experimental evidence suggests that oxidativ e stress and intestinal anaphylaxis may contribute to the intestinal d ysfunction associated with malnutrition, we postulated that zinc could act through antioxidant or antianaphylactic properties. Control (C), malnourished (M), and malnourished zinc-treated (MZ) guinea pigs were, respectively, fed a normal 30% protein diet, a low 4% protein diet, a nd a low 4% protein diet plus 1800 ppm of zinc. Milk proteins were inc luded in the diets to trigger intestinal anaphylaxis. Milk sensitizati on was assessed by passive cutaneous anaphylaxis (PCA) against beta-la ctoglobulin and by intestinal anaphylaxis measured in Ussing chambers by the increase in short circuit-current after addition of beta-lactog lobulin (Delta ISCbeta Lg). Oxidative stress was assessed by intestina l lipid peroxidation. The intestinal secretion was assessed by Delta I SC induced by inflammatory mediators. Malnutrition increased the level of anti-beta Lg reaginic antibodies [PCA = 1.19 +/- 0.79 and 0.69 +/- 0.67 log(1/titer) in M versus C guinea pigs, p = 0.07] and enhanced i ntestinal anaphylaxis (Delta ISCbeta Lg = 16.4 +/- 9.9 and 9.1 +/- 5.8 mu A/cm(2) in M versus C guinea pigs, p = 0.07), without inducing int estinal lipid peroxidation. Moreover, malnutrition enhanced significan tly the intestinal secretory response to histamine and 5-hydroxytrypta mine. Administration of pharmacologic doses of zinc during malnutritio n inhibited the increase in milk sensitization induced by malnutrition , both at the systemic [PCA = 0.35 +/- 0.55 log(1/titer) in MZ guinea pigs, p = 0.03 versus M] and intestinal (Delta ISCbeta Lg = 2.8 +/- 2. 5 mu A/cm(2) in MZ guinea pigs; p = 0.001 versus M) level, and prevent ed the hypersecretion in response to histamine and 5-hydroxytryptamine . These data suggest that zinc has antianaphylactic and antisecretory properties that may contribute to its capacity to prevent intestinal d ysfunction during malnutrition.