Sex differences in effects of gestational polychlorinated biphenyl exposure on hypothalamic neuroimmune and neuromodulator systems in neonatal rats

• Published in: Toxicology and applied pharmacology Vol. 353; pp. 55 - 66
• Main Authors: Bell, Margaret R., Dryden, Ariel, Will, Ryan, Gore, Andrea C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-08-2018
• Subjects: Animals; Animals, Newborn; Corticosterone - blood; Cytokine; Cytokines - blood; Dopamine; Endocrine disrupting chemicals; Estrogen receptor beta; Female; Gene Expression - drug effects; Hypothalamus - drug effects; Hypothalamus - immunology; Inflammation - genetics; Lipopolysaccharide; Lipopolysaccharides - pharmacology; Male; Neuroimmunomodulation - drug effects; Polychlorinated Biphenyls - toxicity; Pregnancy; Rats; Rats, Sprague-Dawley; Sex Characteristics; Sex difference; Lipopolysaccharide; Dopamine; Sex difference; Estrogen receptor beta; Cytokine; Endocrine disrupting chemicals
• ISSN: 0041-008X; 1096-0333; 1096-0333
• DOI: 10.1016/j.taap.2018.06.002

Polychlorinated biphenyls (PCBs) are ubiquitous in the environment and exposure to them is associated with immune, endocrine and neural dysfunction. Effects of PCBs on inflammation and immunity are best described in spleen and blood, with fewer studies on neural tissues. This is an important gap in knowledge, as molecules typically associated with neuroinflammation also serve neuromodulatory roles and interact with hormones in normal brain development. The current study used Sprague-Dawley rats to assess whether gestational PCB exposure altered hypothalamic gene expression and serum cytokine concentration in neonatal animals given an immune challenge. Dams were fed wafers containing a mixture of PCBs at an environmentally relevant dose and composition (20 μg/kg, 1:1:1 Aroclor 1242:1248:1254) or oil vehicle control throughout their pregnancy. One day old male and female offspring were treated with an inflammatory challenge (lipopolysaccharide, LPS, 50 μg/kg, sc) or saline vehicle control approximately 3.5 h prior to tissue collection. Across both basal and activated inflammatory states, PCB exposure caused greater expression of a subset of inflammatory genes in the hypothalamus and lower expression of genes involved in dopamine, serotonin, and opioid systems compared to oil controls. PCB exposure also altered reactions to inflammatory challenge: it reversed the normal decrease in Esr2 hypothalamic expression and induced an abnormal increase in IL-1b and IL-6 serum concentration in response to LPS. Many of these effects were sex specific. Given the potential long-term consequences of neuroimmune disruption, our findings demonstrate the need for further research.
•Perinatal polychlorinated biphenyls (PCBs) alter neonatal hypothalamic gene expression•PCBs reduce expression of dopamine-related targets in males and females•PCBs alter serum cytokine responses to inflammatory LPS differently between sexes•PCBs increase expression of selected neuroimmune signals independent of LPS effect