Prenatal zinc reduces stress response in adult rat offspring exposed to lipopolysaccharide during gestation Marcella C. Galvão a , Gabriela P. Chaves-Kirsten a , Nicolle Queiroz-Hazarbassanov a , Virgínia M. Carvalho a , Maria M. Bernardi b , Thiago B. Kirsten a,b, ⁎ a Department of Pathology, School of Veterinary Medicine, University of São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, Sao Paulo, SP 05508-270, Brazil b Environmental and Experimental Pathology, Paulista University, Rua Dr. Bacelar, 1212, São Paulo, 04026-002, Brazil abstract article info Article history: Received 16 September 2014 Accepted 21 October 2014 Available online 5 November 2014 Keywords: Maternal immune activation Prenatal infection Hypothalamic-pituitary-adrenal axis Ultrasonic vocalizations Open field behavior Norepinephrine Aims: Previous investigations by our group have shown that prenatal treatment with lipopolysaccharide (LPS; 100 μg/kg, intraperitoneally) on gestation day (GD) 9.5 in rats, which mimics infections by Gram-negative bac- teria, induces short- and long-term behavioral and neuroimmune changes in the offspring. Because LPS induces hypozincemia, dams were treated with zinc after LPS in an attempt to prevent or ameliorate the impairments in- duced by prenatal LPS exposure. LPS can also interfere with hypothalamic–pituitary–adrenal (HPA) axis develop- ment; thus, behavioral and neuroendocrine parameters linked to HPA axis were evaluated in adult offspring after a restraint stress session. Main methods: We prenatally exposed Wistar rats to LPS (100 μg/kg, intraperitoneally, on GD 9.5). One hour later they received zinc (ZnSO 4 , 2 mg/kg, subcutaneously). Adult female offspring that were in metestrus/diestrus were submitted to a 2 h restraint stress session. Immediately after the stressor, 22 kHz ultrasonic vocalizations, open field behavior, serum corticosterone and brain-derived neurotrophic factor (BDNF) levels, and striatal and hypothalamic neurotransmitter and metabolite levels were assessed. Key findings: Offspring that received prenatal zinc after LPS presented longer periods in silence, increased loco- motion, and reduced serum corticosterone and striatal norepinephrine turnover compared with rats treated with LPS and saline. Prenatal zinc reduced acute restraint stress response in adult rats prenatally exposed to LPS. Significance: Our findings suggest a potential beneficial effect of prenatal zinc, in which the stress response was reduced in offspring that were stricken with infectious/inflammatory processes during gestation. © 2014 Elsevier Inc. All rights reserved. Introduction Previous investigations by our group have shown that prenatal treatment with lipopolysaccharide (LPS; 100 μg/kg, intraperitoneally) on gestation day (GD) 9.5 in rats, which mimics infections by Gram- negative bacteria, induces short- and long-term behavioral and neuroimmune changes in the offspring. The offspring presented autistic-like behaviors, increased serum interleukin-1β levels, an atten- uated response to experimentally induced asthma, and dopaminergic impairments in the striatum and olfactory bulb [25–28,30,31]. Lipopoly- saccharide exposure also induced sickness behavior in dams, injured placental tissue, and led to higher post-implantation loss and a reduced number of pups born [26,31]. The effects of maternal LPS exposure on the developing fetal brain have been suggested to be mediated by the induction of proinflammatory cytokines within the maternal circulation and placenta [3,10,62]. Cytokines can also activate the hypothalamic–pituitary–adrenal (HPA) axis, leading to increased glucocorticoid levels in peripheral blood, cross- ing the blood brain barrier and influencing brain development processes in the fetus [46]. In the present study, we treated dams with zinc in an attempt to pre- vent or ameliorate the impairments induced by prenatal LPS exposure. We selected zinc for the prenatal treatment because cytokines produced after LPS exposure induce metallothionein, which sequesters zinc and induces maternal and fetal hypozincemia [16]. Coyle's group reported that hypozincemia induced by LPS led to teratogenesis and that zinc supplementation prevented some reproductive and behavioral impair- ments [11,16]. Lipopolysaccharide can interfere with HPA axis development, and adult offspring were evaluated after an acute restraint stress session. When a developing organism suffers maternal immune activation, such as prenatal LPS exposure, the adult offspring may react differently after stressful events (e.g., an increase in their stress response) [20,46]. We previously showed that under basal conditions (i.e., without a stressor challenge), prenatal LPS did not alter behavior or corticosterone Life Sciences 120 (2015) 54–60 ⁎ Corresponding author at: Department of Pathology, School of Veterinary Medicine, University of São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, São Paulo, SP 05508- 270, Brazil. Tel.: +55 11 3091 1372; fax: +55 11 3091 7829. E-mail address: thik@hotmail.com (T.B. Kirsten). http://dx.doi.org/10.1016/j.lfs.2014.10.019 0024-3205/© 2014 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Life Sciences journal homepage: www.elsevier.com/locate/lifescie