Experimental Study Of A Combination Dexmedetomidine And Mild Hypothermia On Inflammatory Reaction In Lung Tissues Of Septic Rats

Objective To study the effects of a combination dexmedetomidine and mild hypothermia on inflammatory reaction in lung tissues of septic rats. Methods Sixty Wistar rats were randomly divided into 5 groups( n=12 each):Sham operation group( group S); control group(group C); dexmedetomidine group(group D); mild hypothermia group( group H);dexmedetomidine and mild hypothermia group( group DH). Sepsis was induced by cecal ligation and incision(CLI). After CLI in the groups S and C,saline was intravenous iniected into the rats; in the group D,dexmedetomidine was injected into the rats;in the group H,saline was intravenous iniected into the rats and body temperature decreased to 32~35℃;while the rats in the group HD,given with dexmedetomidine and body temperature also decreased to 32~35℃. At 0,2,4,8,12 h after CLI,we harvested blood and measured the plasma TNF-α,IL-1 and IL-6concentrations. At 12 h after CLI we harvested lung tissues,the pathological changes of lung tissues were observed by an optical microscope. Results ①2 h after CLI,plasma concentration of TNF-α reached a peak,and then continued to decline;plasma IL-1 and IL-6 concentrations were significantly increased after CLI and then persistently elevated.Compared with group C,TNF-α were significantly lower at 2,4,8,12 h in groups D,H and DH(P <0.05 or P <0.01). TNF-α were significantly lower at 2,4,8h in group DH than group D(P <0.05 or P <0.01). TNF-α were significantly lower at 2,4,8h in group DH than group H(All P <0.05).Compared with group C,IL-1 were significantly lower at 4,8,12 h in groups D,H and DH(P ≤0.01).Moreover,there are no significant difference in IL-1 concentrations in group DH compared with groups D and H(All P >0.05).Compared with group C,IL-6 were significantly lower at 4,8,12 h in groups D,H and DH(All P <0.01).IL-6 were significantly lower at 8,12 h in group DH than group D(All P <0.01). IL-6 were significantly lower at 8,12 h in group DH than group H( P <0.01,P <0.05,respectively).However,there was no significant difference in any of the cytokines measured between groups H and D( AllP >0.05).②Dexmedetomidine and mild hypothermia as well as the combination therapy attenuated the lung histopathologic damage compared with the control group, The histopathologic damages in lungs was more significantly attenuated in group DH than groups D and H. Conclusion Therapeutic dexmedetomidine combined with mild hypothermia have additive beneficial antiinflammatory effects,the combination therapy provides significant protective effects in lung injury compared with either of the two therapies alone.