ABSTRACT
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.