environmental toxicology and pharmacology 34 ( 2 0 1 2 ) 548–555 Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/etap Cadmium effects on early development of chick embryos F.Y. Yamamoto a,∗ , F. Filipak Neto a , P.F. Freitas b , C.A. Oliveira Ribeiro a , C.F. Ortolani-Machado a a Departamento de Biologia Celular, Universidade Federal do Paraná, Caixa Postal 19031, CEP 81.531-990, Curitiba, PR, Brazil b Faculdade Evangélica do Paraná, CEP 80.730-000, Curitiba, PR, Brazil article info Article history: Received 8 November 2011 Received in revised form 12 June 2012 Accepted 23 June 2012 Available online 3 July 2012 Keywords: Cadmium Early stages Gallus gallus Embryos Teratogenic abstract The toxic potential of cadmium (Cd) is well-documented for young and adult vertebrates, but it is still poorly understood in the early stages of development. In this study, cadmium effects were investigated on Gallus gallus embryos after injection of CdCl 2 (5 M and 50 M) within the egg air chamber, and incubation for 48 and 72h. After exposure, morphological and enzymatic analyses for glucose-6-phosphate dehydrogenase (G6PDH) and glutathione S-transferase (GST) were performed. Critical morphological abnormalities occurred after exposure to the highest concentration of cadmium, mainly in the cephalic region, indicating the powerful teratogenic effect of Cd to chick embryos. Cd exposure did not alter enzymatic activities when compared to the control group, but the levels of G6PDH activity were highest in older embryos at stage 19, indicating that antioxidant defenses are not so robust in the earliest embryo stages. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Urban and industrial discharges have been releasing many potentially toxic compounds into the environment for hun- dreds of years. Cadmium (Cd) is particularly important as it is the 7th highest priority hazardous substance accord- ing to the Agency for Toxic Substances and Disease Registry (ATSDR, 2007). Key sources of Cd in the environment include industrial production of pigments, plastic stabilizers, alloys, nickel-cadmium batteries as well improper discharge of many manufactured products (IARC, 1993). In the Earth’s crust, Cd has an average concentration of about 0.1–0.2 mg kg -1 (Ursínyová and Hladíková, 2000; Lalor, 2008), contaminating the air, food and water, and so increas- ing the routes of exposure to animals such as ingestion and inhalation (IARC, 1993). Cadmium is carcinogenic to humans ∗ Corresponding author. Tel.: +55 41 3361 1751; fax: +55 41 3266 2042. E-mail address: fla yama@hotmail.com (F.Y. Yamamoto). (IARC, 1993; Järup and Åkesson, 2009; Waalkes, 2003) and its effects include kidney disease and osteoporosis (Chen et al., 2001; Jin et al., 2004). In pregnant women, Cd can cross the pla- centa at low concentrations, even though the placenta acts as a barrier for toxic substances (Lau et al., 1998; Piasek et al., 2001). Human exposure is increased through cigarette smoke, with studies reporting 0.2–1.0 g of Cd being absorbed by the smoker per cigarette (Lewis et al., 1972). Additionally, abnor- malities in a wide variety of animals such as fish, frogs, rats and birds have been also reported (Brunelli et al., 2011; Man and Woo, 2008; Thompson and Bannigan, 2008; Zhang et al., 2009). The effects of Cd in embryos from different vertebrate groups are an eminent subject of study. Malformation of limbs from mouse embryos was described by Padmanabhan and Hameed (1990). Cheng et al. (2001) and Hallare et al. (2005) reported abnormalities of the heart, vasculature and liver in 1382-6689/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.etap.2012.06.010