Effects of QA 208‐199 and its metabolite 209‐668 on embryonic development in vitro after microinjection into the exocoelomic space or into the amniotic cavity of cultured rat conceptuses

Abstract

The objective of this study was to determine the direct embryotoxic effects in vitro of N-hydroxy-N-methyl-7-propoxy-2-naphthalene-ethanamine (QA 208-199, QAB) and of one of its metabolites, 7-propoxy-naphthalene-2-ylacetic acid (209-668, QAA), after circumventing the bioconverting conceptual membranes. The compounds were, therefore, microinjected either into the exocoelomic space or into the amniotic cavity of rat conceptuses of 10 d at prenatal age at doses of up to 84.9 ng (QAA) and 180 ng (QAB) per conceptus respectively. The conceptuses were subsequently cultured for 28 h after which their development was assessed. QAB produced marginal effects on embryonic differentiation only after microinjection of the compound into the amniotic cavity. Dysmorphogenic effects, however, occurred in a dose-dependent fashion after either exocoelomic or intraamniotic microinjections of the compound. The frequencies and types of anomalies were similar after either exposure route and consisted predominantly of anomalies associated with axial rotation. QAA also impaired embryonic differentiation at only the high dose level of 84.9 ng per embryo and after intraamniotic injections only. Dysmorphogenic effects were observed in all experimental groups, although the differences were not statistically significant when compared with the concomitant controls. An increased proportion of anomalies observed were in the cephalic region as compared to the defects produced by QAB. These data suggest that QAA most probably is not the QAB metabolite responsible for the embryotoxic action of QAB in vitro. Furthermore, the results tend to confirm the suggested involvement of the visceral yolk sac membrane in mediating QAB embryotoxicity.

Zebrafish: An Animal Model for Toxicological Studies

“…Several mammalian models are typically used for developmental toxicity studies, including rat and mouse whole-embryo, organ, and tissue cultures (Chatot et al, 1980;Cicurel and Schmid, 1988). However, mammalian whole-embryo cultures are complicated: embryos must be explanted with the visceral yolk sac and ectoplacental cone intact for culture, and the embryo culture time is limited to 48 hr (Bechter et al, 1991). Partly due to the embryonic attributes described above, zebrafish is a much simpler model system for assessing toxicity.…”

The Validation and Use of In Vitro Teratogenicity Tests

“…A variety of media have been used with either species. Rat serum which can be diluted up to 50 % with composition salt solutions works well for the rat (Bechter et al 1991;Terlouw et al 1993) and mouse (Sadler 1979), but also serum from cows (Klug et al 1985), monkeys (Klein et al 1982) and humans (Chatot et al 1980;Van MaeleFabry et al 1993a, Abir et al 1993) allows satisfactory embryonic growth. Serum from rabbits diluted up to 40 % has been shown to support rabbit embryonic growth in vitro (Ninomiya et al 1993).…”

Review of current and “omics” methods for assessing the toxicity (genotoxicity, teratogenicity and nephrotoxicity) of herbal medicines and mushrooms

“…This allows probing major aspects of organogenesis, including heart development, closure of the neural tube, development of ear and eye, brachial bars and limb buds; disturbance during this period may lead to general retardation of growth and development or to specific malformations in one or several organs (Brown et al, 1995;Spielmann, 2005). Drug-metabolizing enzymes can be incorporated and concentrations of tested compounds and metabolites can easily be monitored in the culture medium and in embryonic tissues (Bechter et al, 1991). Mouse or rat embryos with 2-5 somites are explanted from the uterus, cultured (Piersma et al, 2004;Paniagua-Castro et al, 2008;de Jong et al, 2011) and exposed to various concentrations of the tested compounds.…”