To Investigate The Impact Of Mild Hypothermia On TLR4and Inflammatory Balance Of Macrophage Cellline

Objective: To investigate the impact of Mild hypothermia on TLR4mRNAtranscription of the macrophage cell line RAW264.7and downstreaminflammatory balance with the intervention of lipopolysaccharide（LPS）.Methods: Administering the RAW264.7cell line with LPS in the trialgroup, equivalent saline was added in control group, the cells were incubated in37°C and32°C respectively for2hours,8hours,24hours,designated asNormalthermia Control Group:2H,8H,24H;Normalthermia Trial Group:2H,8H,24H;Hypothermia Trial Group:2H，8H，24H.In each timepoint the cellculture medium was extracted to detect IL-1β and IL-10concentrations; usingTrizol to extract total RNA, which was later reverse transcripted, and thenTLR4mRNA transcriptional level was detected by RT-PCR.Results: Under the intervention of LPS, TLR4mRNA transcriptional levelof both groups first increased and then showed a decreasing trend and at eachtimepoint TLR4mRNA transcription level of mild hypothermia group was lower than that of the normothermia group(2H:9.19±0.57vs10.08±1.02,P＝0.036,8H:13.58±1.57vs15.24±1.63，P＝0.042,24H:6.85±1.17vs8.17±1.21，P＝0.032）. After administering with LPS, IL-1β and IL-10levels in bothnormal and mild hypothermia group were gradually increased over time.At eachtimepoint,the level of IL-1β of mild hypothermia group was lower than that ofnormothermia group,whereas the level of IL-10of mild hypothermia group washigher than that of normothermia group.The IL-1β/IL-10ratio of normothermiagroup was gradually increased,which of the hypothermia group decreased by thepassage of time.Of note,at each timepoint, IL-1β/IL-10ratio of mildhypothermia group was lower than that of normothermia group（2h:0.740±0.214vs0.993±0.256,P=0.037;8h:0.701±0.363vs1.237±0.455,P=0.014;24h：0.493±0.292vs2.099±0.428,P<0.001）.Conclusion: Mild hypothermia can reduce TLR4mRNA transcription levelof RAW264.7macrophage after the administration of LPS, and lowered thelevel of IL-1β comparably, but retained a higher level of IL-10, thus renderedthe inflammation balance developing toward anti-inflammatory direction.