[Mild hypothermia inhibits TLR4 activation and the expression of inflammatory cytokines induced by lipopolysaccharide in BV-2 mice microglias].

OBJECTIVE: To investigate the impact of mild hypothermia on the lipopolysaccharide (LPS)-induced expressions of Toll-like receptor 4 (TLR4), nuclear factor κB (NF-κB) and downstream inflammatory cytokines in BV-2 microglias. METHODS: BV-2 cells cultured in vitro were divided into 33 Degrees Celsius-PBS, 33 Degrees Celsius-LPS, 37 Degrees Celsius-PBS and 37 Degrees Celsius-LPS groups. Real-time quantitative PCR was performed to detect the mRNA expressions of TLR4 and NF-κB in BV-2 cells, Western blotting was performed to detect the protein expressions of TLR4 and NF-κB in BV-2 cells, and ELISA to detect the levels of tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) in the culture medium. RESULTS: After LPS stimulated BV-2 cells, TLR4 pathway protein exhibited the trend of increasing firstly and decreasing afterwards, while the expression of NF-κB protein in the pathway downstream continued to increase, and the release of inflammatory cytokines TNF-α and IL-1β were significantly promoted. Mild hypothermia could significantly inhibit the transcription and expressions of TLR4 and NF-κB as well as the release of inflammatory cytokines. CONCLUSION: The mild hypothermia could inhibit the LPS/TLR4 pathway in BV-2 cells, and depress the expressions of TNF-α and IL-1β.