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Objective To investigate the effects of inducible hypothermia on expressions of peroxisome proliferator activated receptor gamma coactivator-1 (PGC-1) and small heterodimer partner (SHP) in rat model of hemorrhagic shock.Methods SD rats were randomly (random number) divided into three groups:control (C),normothermia (N) and hypothermia (H).Exsanguination was carried out in rats by continuously drawing out venous blood (25 mL/kg) over 15 minutes to establish hemorrhagic shock model.Then,rectal temperatures of rats were maintained by body surface cooling to 32℃ in H group and by body surface warming to 38℃ in N group,respectively.After a shock period of 60 minutes,rats received the infusion of whole blood of their own and lactated Ringer's solution (1 ∶ 2) treatment for 60 min.Rats were warmed to 38℃ by body surface warming and monitored for 3 h after resuscitation.Hematocrit (Hct),base excess (BE),lactate (Lac),and glucose (Glu) were recorded before modeling and after different lengths of hemorrhagic shock period (HSP).The expressions of PGC-1 mRNA and SHP mRNA and the levels of their protein in liver were tested by real-time reverse transcription polymerase chain reaction (qRT-PCR) and western blotting,respectively.Results The H group had lower lactate levels and higher BElevels than the N group [(6.3±2.1) vs.(10.4±1.5) and (-4.7±2.5) vs.(-9.0±3.2)] (P＜ 0.05).At 72 hours after modeling,there were four survivors in the N group and seven survivors in the H group (P ＜ 0.05,Log Rank).The expressions of PGC-1 mRNA and SHP mRNA increased in N group.Hypothermia resuscitation down-regulated PGC-1 mRNA expression,meanwhile,increased expression of SHP mRNA.Both Hypothermia and Normothermia resuscitation increased SHP protein levels,but decreased PGC-1 protein levels.Conclusions Inducible hypothermia ameliorated acidosis and energy metabolism imbalance through adaptive regulation in PGC-1 and SHP.
RESUMEN
Objective To investigate the effects of environmental hypothermia on hemodynamics and oxygen metabolism in unanesthetized swine model of hemorrhagic shock.Methods A total of 16 Bama pigs provided by animal experiment centre of the General Hospital of Shenyang Military Command were randomized into two groups ( n =8,each):ambient temperature (A) and hypothermia ( H ).Venous blood (30 mL/kg) was continously withdrawn over 15 minutes to establish hemorrhagic shock model.Core temperature,heart rate,mean arterial pressure,central venous pressure,cardiac output,saturation of mixed venous blood and blood gas analysis were recorded at the baseline and different hemorrhagic shock time.DO2I and VO2I,and the O2 extraction ratio (O2ER) were calculated.Results Core body temperature in group A decreased slightly after hemorrhagic shock model had established and environmental hypothermia resulted in more reduction in core body temperature.The mortality rate was significantly higher in group H (50％) than in group A (0％) (P ＜0.05).DO2I and VO2I decreased significantly after hemorrhage.No difference was found in hemodynamics,DO2I and VO2I between group A and group H,but the difference of pH,lactic acid and O2ER were significant between the two groups (P ＜ 0.05 ).conclusions Environmental hypothermia aggravated the disorder of oxygen metabolism after hemorrhagic shock,which was associated with poor prognosis.