Summary
Microglia effects: Early life exposure to EC with or without nicotine did not induce changes in the expression of GFAP. Male and female offspring exposed to EC vapor without nicotine showed significant increase in mean intensity for Iba-1 in the CA1 region. EC exposure without nicotine increased Iba-1 mean intensity in the frontal cortex region for mice exposed to EC vapor with and without nicotine compared to control mice; however, no changes in Iba-1 expression was observed on the cornus ammonis 3 (CA3) and dentate gyrus (DG) regions of hippocampus.
Neurotrophins in the hippocampus and frontal cortex: Ngfr and Bdnf gene expression levels were significantly decreased in the hippocampus of offspring exposed early in life to EC aerosols with and without nicotine compared to controls. Peripheral Inflammation: IL-1β and IL-2 levels were significantly decreased for both sexes of offspring exposed to EC aerosol with and without nicotine compared to sex-pooled air controls. Offspring exposed to EC aerosol without nicotine had generally lower levels of IL-6 compared to the air controls. There were no effects on TNFα, MCP-1, or IFN-γ levels. Neuroinflammation: Early life exposure in offspring exposed to EC aerosol without nicotine displayed 27 and 24 altered genes overlapping with the Ingenuity Pathway Analysis (IPA) "affects inflammation of the CNS" molecule list in males and females, respectively. Early life exposure to EC aerosol with nicotine induced changes in 6 genes in males and 13 genes in females.
Author Conclusions
1. Microglia activation was induced in offspring exposed early in life to e-cigarette aerosols without nicotine 2. Gene expression levels of neurotrophins and serum levels of cytokines are reduced in offspring exposed during early life to e-cigarette aerosols both with and without nicotine 3. Disruption of CNS development could be due to exposure to e-cigarette constituents other than nicotine
Citation
Zelikoff, J.T., et al. (2017). Microglia activation and gene expression alteration of neurotrophins in the hippocampus following early-life exposure to e-cigarette aerosols in a murine model. Toxicological Sciences, 162(1), 276-286.
