Combined effect of hypothermia and crystalloid hemodilution on the solubility of volatile anesthetics in human blood

OBJECTIVE: To determine the combined effect of hypothermia and crystalloid hemodilution on blood solubility of volatile anesthetics. METHODS: Two hundred and thirty ml blood samples obtained from each of twelve healthy male volunteers were adjusted to a hematocrit of 40% and then diluted with normal saline to hematocrits of 36%, 32%, 28%, 24%, and 20%. Blood/gas partition coefficients of desflurane, sevoflurane, isoflurane, enflurane and halothane were measured at 37 degrees C,33 degrees C, 29 degrees C, 25 degrees C, 21 degrees C and 17 degrees C using a two-stage headspace double equilibration method. RESULTS: As the temperature decreased, the logarithm of the blood/gas partition coefficient increased linearly (P

Effect of acupuncture plus mild hypothermia on MAPK/ERK pathway of brain tissues in rats with cerebral ischemia-reperfusion injury

Objective： To observe the protective effect of acupuncture plus mild hypothermia on brain tissues in rats with cerebral ischemia-reperfusion injury （CIRI）, and the influence on protein expression levels of phosphorylated Raf-1, MEK-2 and ERK3/2 in the mitogen-activated protein kinase （MAPK）/extracellular regulated protein kinases （ERK） pathway, and to explore the mechanism of acupuncture plus mild hypothermia therapy for the ischemic stroke. Methods： Ninety Sprague-Dawley （SD） rats were randomly divided into a blank control group, a sham operation group, a model group, an acupuncture group, a mild hypothermia group and an acupuncture plus mild hypothermia group, 15 rats in each group. Except the rats in the blank control group, the remaining rats were used to prepare the middle cerebral artery occlusion （MCAO） models according to the modified occlusion method using lines, while only the occlusion lines were inserted without blocking the brain arteries of rats in the sham operation group. When the vital signs of rats were stable, rats in the blank control group did not receive any intervention; rats in the sham operation group and the model group received fastening without treatment; rats in the acupuncture group, the mild hypothermia group, and the acupuncture plus mild hypothermia group were treated with the corresponding therapeutic methods. 72 h later, observed neurologic injury score, evaluated infarction area ratio by 2,3,5-tripheyl tetrazolium chloride （TTC） staining, determined apoptosis by TUNEL assay, and measured the phosphorylated Raf-1, MEK-2 and ERK3/2 protein expression levels in rat ischemic hippocampal tissues by Western blot assay. Results： Compared with the blank control group and the sham operation group, after modeling, the neurologic injury score, infarction area ratio and apoptotic cells were increased, and phosphorylated Raf-1, MEK-2 and ERK：1/2 protein expression levels were significantly increased in the model group; the differences were statistically significant （P〈0.05 or P〈0.01）. Compared with the model group, after acupuncture or mild hypothermia therapy, neurologic injury score and infarction area ratio were decreased; apoptotic cells and phosphowlated Raf-1, MEK-2 and ERK1/2 protein expression levels were significantly decreased; the differences were statistically significant （P〈0.05 or P〈0.01）. Compared with the acupuncture group, neurologic injury score and phosphorylated Raf-1, MEK-2 and ERK3/2 protein expression levels were decreased in the acupuncture plus mild hypothermia group; differences between the groups were statistically significant （P〈0.05 or P〈0.01）. Compared with the mild hypothermia group, phosphorylated Raf-1, MEK-2 and ERK1/2 protein expression levels decreased in the acupuncture plus mild hypothermia group, and differences were statistically significant （P〈0.01）. Conclusion： Acupuncture or mild hypothermia therapy can improve neurologic injury, reduce infarction area and apoptosis, which brought about protective effect on the brain tissues, in the MCAO model. The protective effect of acupuncture plus mild hypothermia group is the strongest. The mechanism may involve the MAPK/ERK pathway, by reducing the phosphorylated Raf-l, MEK-2 and ERK：1/2 protein expression levels.

Exploring the effect of acupuncture plus mild hypothermia on miRNA-204 and its target gene expressions in CIRI rat brain tissues based on MAPK signal pathway

Objective:To explore the protective mechanism of acupuncture plus mild hypothermia for cerebral ischemia-reperfusion injury(CIRI)by observing the effects of acupuncture plus mild hypothermia on miRNA-204 and its target gene expressions in CIRI rat brain tissues.Methods:Sixty Sprague-Dawley rats were divided into a blank control group,a sham operation group,a model group,an acupuncture group,a mild hypothermia group and an acup un cture plus mild hypothermia group accordi ng to the random nu mbertable method(n=10).Except for the blank c on trol group an dthe sham operati on group,rats in the other 4 groups received CIRI modeling.After the model was successfully established,rats in the blank control group were bred routinely for 72 h without any interventions;rats in the sham operation group and the model group were bred routinely for 72 h,and only received bin ding without other interve ntions after surgery;rats in the acup un cture group were bred routinely for 72 h,and received acupuncture at Dazhui(GV 14),Baihui(GV 20)and Shuigou(GV 26)after binding;rats in the mild hypothermia group were bred routinely for 72 h,and received mild hypothermia intervention for 72 h after binding;rats in the acupuncture plus mild hypothermia group were bred routinely for 72 h,followed by receiving acupuncture as in the acup uncture group and mild hypothermia therapy as in the mild hypothermia group after bin ding.The n eurological impairme nt score,cerebral infarcti on area ratio,the expressions of miRNA-204 and its target genes in eluding Map3k8,Ntrk2 and Ppp3rl in the ischemic hippocampus of each group were observed after 72 h of intervention.Results:Before intervention,compared with the bgnk control group and the sham operation group,the neurological impairment scores and the infarction area ratios of the modelled rats were statistically significa ntly increased(all P<Q.Ql)f indicating that the model was successful.After intervention,compared with the model group,the neurological impairment scores of the three in tervention groups were sign ifica ntly reduced(all P<0.01);compared with the acupuncture group and the mild hypothermia group,the infarction area ratio in the acupuncture plus mild hypothermia group was signtiicantly reduced(both P<0.01);compared with the model group,the three intervention groups showed significant inhibition of miRNA-204 expression in brain tissues(all P<0.05),which was most significant in the acupuncture plus mild hypothermia group(P<0.01);compared with the acupuncture group and the mild hypothermia group,the Map3k8 expression in the acupuncture plus mild hypothermia group was significantly increased(both P<0.01),but there were no sign ificant d iff ere nces in Ntrk2 and Ppp3rl expressions between groups(all P>0.05).Conclusion:Acupuncture,mild hypothermia,and acupuncture plus mild hypothermia reduced the neurological impairment score and the cerebral infarction area in CIRI rats,while acupuncture plus mild hypothermia showed the most significant effect.In regulating miRNA-204 target gene expressions,acupuncture plus mild hypothermia showed the same effect on Ntrk2 and Ppp3rl expressions,while better effect on Map3k8 expression compared with either acupuncture or hypothermia.