Chronic Ethanol Exposure Induces Neuroinflammation in H4 cells through TLR3 / NF-κB Pathway and Anxiety-like Behavior in Male C57BL/6 Mice.

Chronic alcoholism has become a major public health problem. Long-term and excessive drinking can lead to a variety of diseases. Chronic ethanol exposure can induce neuroinflammation and anxiety-like behavior, and this may be induced through the Toll-like receptor 3/nuclear factor-kappa B (TLR3/NF-kappa B) pathway. Animal experiments were performed using healthy adult male C57BL/6 N mice given 10 % (m/V) or 20 % ethanol solution as the only choice of drinkable fluid for 60, 90 or 180 d. In cell culture experiments, H4 human glioma cells were treated with 100 mM ethanol for 2 d, with the TLR3 gene silenced by RNAi and NF-kappa B inhibited by ammonium pyrrolidine dithiocarbamate (PDTC, 10 mu M). After treatment with ethanol solution for a specific time, the anxiety like behavior of the mice was tested using the open field test and the elevated plus maze test. Western blotting was used to detect the expression of TLR3, TLR4, NF-kappa B, IL-1 beta, IL-6, and TNF-alpha in the mouse hippocampus and H4 cells. The expression of IL-1 beta, IL-6 and TNF-alpha in the supernatant of cell culture medium was detected by ELISA. The open field test showed a decrease in time spent in the central area, and the elevated plus maze test showed a decrease in activity time in the open arm region. These behavioral tests indicated that ethanol caused anxiety-like behavior in mice. The expression levels of TLR3, TLR4, NF-kappa B, IL-1 beta, IL-6, and TNF-alpha increased after ethanol exposure in both the hippocampus of mice and H4 cells. Silencing of the TLR3 gene by RNAi or inhibition of NF-kappa B by PDTC attenuated the ethanol-induced increase in the expression of inflammatory factors in H4 cells. These findings indicated that chronic ethanol exposure increases the expression of TLR3 and NF-kappa B and produces neuroinflammation and anxiety-like behavior in male C57BL/6 mice and that ethanol-induced neuroinflammation can be caused through the TLR3/NF-kappa B pathway.