P23: Histopathological assessment of juvenile rat tissues treated with the food contaminant semicarbazide: Preliminary findings

Abstract

Semicarbazide (SEM) is a food contaminant, by-product of azodicarbonamide sealing for gaskets of jar lids for baby foods. Toxicological data on SEM are insufficient; studies in rodents showed osteolathyrogenic effects in foetuses and potential carcinogenicity, but not genotoxicity. To characterize hazards for children, juvenile Sprague-Dawley rats of both sexes are exposed po to SEM from PND 23 to PND 60 at dose levels of 0 (vehicle only – distilled water), 40, 75 and 140 mg/kg bw day. During the treatment, body weight gain and food consumption are recorded; vaginal opening and preputial separation are observed to evaluate the development of reproductive system. At sexual maturity rats are sacrificed and tissues/organs are collected for histological analysis, with attention to endocrine, immune and skeletal systems: thyroid, adrenals, testes, spleen, uteri and ovaries, thymus, coxal-femoral joint. Body weight gain is reduced in males at 75–140 mg/kg. Food consumption is reduced in both sexes at 140 mg/kg and increased in females at 75 mg/kg. Vaginal opening is delayed in all treated groups; preputial separation is anticipated at 40 and 75 mg/kg and delayed in the high dose group. Histology of thyroid showed in all treated males increased desquamation in follicular lumen; in females this is present only at 140 mg/kg. Adrenal alterations are present in females only: cortex vacuolization (all dose groups) and blurred zonation architecture (high dose only), in medulla increased cell degeneration (high dose). In the spleen, increased haematopoiesis is present in males (high dose), with a dose-related trend at mid-dose. Such preliminary observations show alterations in endocrine and immune tissues. Altered timing in sexual maturation, adrenal cortex and thyroid effects are present also at 40 mg/kg, without evident general toxicity, supporting the need for toxicological studies on food and environmental contaminants targeted to juvenile lifestages.