Neuroprotective effects of cold-inducible RNA-binding protein during mild hypothermia on traumatic brain injury

Cold-inducible RNA-binding protein（CIRP）, a key regulatory protein, could be facilitated by mild hypothermia in the brain, heart and liver. This study observed the effects of mild hypothermia at 31 ± 0.5℃ on traumatic brain injury in rats. Results demonstrated that mild hypothermia suppressed apoptosis in the cortex, hippocampus and hypothalamus, facilitated CIRP m RNA and protein expression in these regions, especially in the hypothalamus. The anti-apoptotic effect of mild hypothermia disappeared after CIRP silencing. There was no correlation between mitogen-activated extracellular signal-regulated kinase activation and CIRP silencing. CIRP silencing inhibited extracellular signal-regulated kinase-1/2 activation. These indicate that CIRP inhibits apoptosis by affecting extracellular signal-regulated kinase-1/2 activation, and exerts a neuroprotective effect during mild hypothermia for traumatic brain injury.

Mild hypothermia combined with a scaffold of Ng Rsilenced neural stem cells/Schwann cells to treat spinal cord injury

Because the inhibition of Nogo proteins can promote neurite growth and nerve cell differentiation, a cell-scaffold complex seeded with Nogo receptor （NgR）-silenced neural stem cells and Schwann cells may be able to improve the microenvironment for spinal cord injury repair. Previous studies have found that mild hypothermia helps to attenuate secondary damage in the spinal cord and exerts a neuroprotective effect. Here, we constructed a cell-scaffold complex consisting of a poly（D,L-lactide-co-glycolic acid） （PLGA） scaffold seeded with NgR-silenced neural stem cells and Schwann cells, and determined the effects of mild hypothermia combined with the cell-scaffold complexes on the spinal cord hemi-transection injury in the T9 segment in rats. Compared with the PLGA group and the NgR-silencing cells ＋ PLGA group, hindlimb motor function and nerve electrophysiological function were dearly improved, pathological changes in the injured spinal cord were attenuated, and the number of surviving cells and nerve fibers were increased in the group treated with the NgR-silenced cell scaffold ＋ mild hypothermia at 34℃ for 6 hours. Furthermore, fewer pathological changes to the injured spinal cord and more surviving cells and nerve fibers were found after mild hypothermia therapy than in injuries not treated with mild hypothermia. These experimental results indicate that mild hypothermia combined with NgR gene-silenced cells in a PLGA scaffold may be an effective therapy for treating spinal cord injury.

Mild hypothermia for treatment of diffuse axonal injury: a quantitative analysis of diffusion tensor imaging

Fractional anisotropy values in diffusion tensor imaging can quantitatively reflect the consistency of nerve fibers after brain damage, where higher values generally indicate less damage to nerve fibers. Therefore, we hypothesized that diffusion tensor imaging could be used to evaluate the effect of mild hypothermia on diffuse axona[ injury. A total of 102 patients with diffuse axonal injury were randomly divided into two groups： normothermic and mild hypothermic treatment groups. Patient＇s modified Rankin scale scores 2 months after mild hypothermia were significant- ly lower than those for the normothermia group. The difference in average fractional anisotropy value for each region of interest before and after mild hypothermia was 1.32-1.36 times higher than the value in the normothermia group. Quantitative assessment of diffusion tensor imaging indicates that mild hypothermia therapy may be beneficial for patients with diffuse axonal injury.

The pathways by which mild hypothermia inhibits neuronal apoptosis following ischemia/reperfusion injury

Several studies have demonstrated that mild hypothermia exhibits a neuroprotective role and it can inhibit endothelial cell apoptosis following ischemia/reperfusion injury by decreasing casp- ase-3 expression, It is hypothesized that mild hypothermia exhibits neuroprotective effects on neurons exposed to ischemia/reperfusion condition produced by oxygen-glucose deprivation. Mild hypothermia significantly reduced the number of apoptotic neurons, decreased the expres- sion of pro-apoptotic protein Bax and increased mitochondrial membrane potential, with the peak of anti-apoptotic effect appearing between 6 and 12 hours after the injury. These findings indicate that mild hypothermia inhibits neuronal apoptosis following ischemia/reperfusion injury by protecting the mitochondria and that the effective time window is 6-12 hours after ischemia/reperfusion injury.

Mild hypothermia in improving multiple organ dysfunction after cardiac arrest

BACKGROUND： Resuscitation after cardiac arrest （CA） with a whole-body ischemia–reperfusion injury causes brain injury and multiple organ dysfunction （MODS）. This study aimed to determine whether mild systemic hypothermia could decrease multiple organ dysfunctions after resuscitation from cardiac arrest.METHODS： The patients who had been resuscitated after cardiac arrest were reviewed. During the resuscitation they had been assigned to undergo therapeutic hypothermia （target temperature, 32°C to 34°C, measured in the rectum） over a period of 24 to 36 hours or to receive standard treatment with normothermia. Markers of different organ injury were evaluated for the ？ rst 72 hours after recovery of spontaneous circulation （ROSC）.RESULTS： At 72 hours after ROSC, 23 patients in the hypothermia group for whom data were available had favorable neurologic, myocardial, hepatic and pulmonic outcomes as compared with 26 patients in the normothermia group. The values of renal function were not signi？ cantly different between the two groups. However, blood coagulation function was badly injured in the hypothermia group.CONCLUSION： In the patients who have been successfully resuscitated after cardiac arrest, therapeutic mild hypothermia can alleviate dysfunction after resuscitation from cardiac arrest.

Mild hypothermia effects on matrix metalloproteinase-9 expression in the perihematomal region of rats following experimental intracerebral hemorrhage

BACKGROUND： Matrix metalloproteinase-9 （MMP-9） expression increases with intracerebral hemorrhage, and participates in the pathophysiological processes of secondary brain injury after intracerebral hemorrhage. OBJECTIVE： To investigate the effects of mild hypothermia on MMP-9 expression and brain edema in the perihematomal region of experimental intracerebral hemorrhage rats. DESIGN, TIME AND SETTING： The randomized, controlled experiment was performed at the Central Laboratory of Shandong Provincial Hospital between May and September 2007. MATERIALS： Seventy-two, Wistar, male rats, 12-weeks old, were used for this study. Rabbit anti-MMP-9 primary antibody was purchased from Boster, China. METHODS： Wistar rats were equally and randomly divided into normothermia and mild hypothermia groups. The two groups each comprised control, 6-hour intracerebral hemorrhage, 24-hour intracerebral hemorrhage, 48-hour intracerebral hemorrhage, 72-hour intracerebral hemorrhage, and l-week intracerebral hemorrhage subgroups, with six rats in each subgroup. Rat models of intracerebral hemorrhage were established by injecting 100 μL of autologous blood into the rat caudate nucleus. Rats in the mild hypothermia group received four hours of local mild hypothermia immediately following the injection. lntracerebral temperature was maintained at （33 ± 0.5） ℃. Subsequently, intracerebral temperature was spontaneously recovered at 25 ℃. Rats in the control subgroup were not injected with autologous blood and received only with intracerebral hemorrhage. MAIN OUTCOME MEASURES： Brain water content and MMP-9 expression surrounding the hematoma region. RESULTS： MMP-9 expression increased at 6 hours, and brain edema reached a peak at 48 hours after intracerebral hemorrhage. MMP-9 expression was significantly decreased in the mild hypothermia group compared with the normothermia group at each time point （P 〈 0.05）. CONCLUSION： Mild hypothermia can significantly inhibit MMP-9 overexpression and relieve brain edema following intracerebral hemorrhage.

Effects of mild hypothermia on the expression of microtubule-associated protein 2 in neurons of the hippocampal dentate gyrus in a rat model of cerebral ischemia/reperfusion

BACKGROUND： It is widely accepted that mild hypothermia can protect against injury to cerebral ischemia/reperfusion. OBJECTIVE： To observe the effects of mild hypothermia on microtubule-associated protein 2 （MAP2） expression in the hippocampal dentate gyms in rats following cerebral ischemia/reperfusion. Also, to study neuronal ultrastmctural changes in the dentate gyms to investigate the mechanism of the protection against injury to cerebral ischemia/reperfusion conferred by mild hypothermia. DESIGN, TIME AND SETTING： This randomized grouping, neural cell morphology trial was performed at the Laboratory Animal Center of Yijishan Hospital between March and June 2007. MATERIALS： Eighty-five healthy male Sprague Dawley rats were randomly allocated to three groups： mild hypothermia （n = 40）, normothermia （n = 40）, and sham-operated （n = 5）. METHODS： Cerebral ischemia/reperfusion injury was induced by the suture method in the mild hypothermia and normothermia groups, with a threading depth of 180.5 mm. In the sham-operated group, the suture was inserted 15 mm, with no vascular ligafion, and was followed by reperfusion 2 hours later. In the sham-operated and normothermia groups, the rat rectal temperature was maintained at 36-37 ℃ ; in the mild hypothermia group, it was controlled at 32-33 ℃. MAIN OUTCOME MEASURES： The hippocampal dentate gyms was serially sectioned for hematoxylin-eosin staining and MAP2 immunohistochemistry. Ultrastructural changes and the MAP2 absorbance value of the hippocampal dentate gyms were examined by transmission electron microscopy. RESULTS： The sham-operated group exhibited approximately normal ultrastructure of neurons in the bilateral hippocampal dentate gyms. In the normothermia group, ischemic hippocampal dentate gyms neurons were found with markedly fewer normal mitochondria, greatly proliferated rough endoplasmic reticulum, and a swollen and dysmorphic Golgi. In the mild hypothermia group, at each corresponding time point, these abnormal changes were noticeably alleviated. The number of necrotic mitochondria, as well as the degree of degeneration, was obviously reduced compared with the normothermia group. At days 6, 8 and 10 following reperfusion, the normothermia group exhibited lower neurological function scores than the mild hypothermia group （P 〈 0.05）. In the normothermia group, the absorbance value of MAP2 expression in the ischemic hippocampal dentate gyms was significantly decreased compared with the sham-operated group （P 〈 0.01 ）, was slightly increased at 4 days, and reached a peak on day 8. The mild hypothermia group showed an absorbance value of MAP2 expression in the ischemic hippocampal dentate gyms similar to the normothermia group, but it reached a peak on day 6. On days 1, 2, 4 and 6 following repeffusion, MAP2 expression was lower in the mild hypothermia group than in the sham-operated group, but it was higher than the normothermia group （P 〈 0.05）. CONCLUSION： Mild hypothermia applied in early ischemia can alleviate brain injury. This may be due to an enhancement of MAP2 expression.

Therapeutic benefits of mild hypothermia in patients successfully resuscitated from cardiac arrest:A meta-analysis

BACKGROUND:Good neurological outcome after cardiac arrest(CA) is hard to achieve for clinicians.Experimental and clinical evidence suggests that therapeutic mild hypothermia is beneficial.This study aimed to assess the effectiveness and safety of therapeutic mild hypothermia in patients successfully resuscitated from CA using a meta-analysis.METHODS:We searched the MEDLINE(1966 to April 2012),OVID(1980 to April 2012),EMBASE(1980 to April 2012),Chinese bio-medical literature & retrieval system(CBM)(1978 to April 2012),Chinese medical current contents(CMCC)(1995 to April 2012),and Chinese medical academic conference(CMAC)(1994 to April 2012).Studies were included if 1) the study design was a randomized controlled trial(RCT);2) the study population included patients successfully resuscitated from CA,and received either standard post-resuscitation care with normothermia or mild hypothermia;3) the study provided data on good neurologic outcome and survival to hospital discharge.Relative risk(RR) and 95%confidence interval(CI) were used to pool the effect.RESULTS:The study included four RCTs with a total of 417 patients successfully resuscitated from CA.Compared to standard post-resuscitation care with normothermia,patients in the hypothermia group were more likely to have good neurologic outcome(RR=1.43,95%CI 1.14-1.80,P=0.002) and were more likely to survive to hospital discharge(RR=1.32,95%CI 1.08-1.63,P=0.008).There was no significant difference in adverse events between the normothermia and hypothermia groups(P>0.05),nor heterogeneity and publication bias.CONCLUSION:Therapeutic mild hypothermia improves neurologic outcome and survival in patients successfully resuscitated from CA.

Mild hypothermia effects on intercellular adhesion molecule-1 and serum interleukin-6 expression in brain tissues of a rat focal ischemia model

BACKGROUND： Previous studies have confirmed the neuroprotective effect of mild hypothermia on ischemic brain injury. OBJECTIVE： To investigate the effects of mild hypothermia on intercellular adhesion molecule-1 expression and serum interleukin-6 levels in ischemic brain tissues of focal brain ischemia rats, and to explore the neuroprotective effects of mild hypothermia on ischemic brain injury. DESIGN, TIME AND SETTING： A randomized, controlled, neurobiological experiment was performed at the Central Laboratory, First Affiliated Hospital, Xinxiang Medical College, China from February to July 2006. MATERIALS： Thirty healthy, adult, Sprague Dawley rats were used to establish middle cerebral artery occlusion models using the suture method, The immunohistochemistry （streptavidin-biotin-peroxidase complex method） kit was purchased from Boster, China. Interleukin-6 radioimmunoassay was supplied by Institute of Radioimmunity, Technology Development Center, General Hospital of Chinese PLA. METHODS： The rats were equally and randomly assigned into mild hypothermia and control groups, and middle cerebral artery occlusion models were established. The rectal temperature was maintained at （37 ±0.5）℃ in the control group. In the mild hypothermia group, the rectal temperature was maintained at （33±1）℃. MAIN OUTCOME MEASURES： At 12 hours after model establishment, the ischemic brain hemispheres were coronally sliced at the level of the optic chiasm. The number of intercellular adhesion molecule-1-positive vessels per high-power field was observed with an optical microscope. Serum interleukin-6 levels were measured by radioimmunoassay. RESULTS： Compared with the control group, intercellular adhesion molecule-1 and serum interleukin-6 expressions were significantly decreased in ischemic brain tissues of the mild hypothermia group （P 〈 0.01）. CONCLUSION： Mild hypothermia exhibits a neuroprotective effect by reducing serum interleukin-6 and intercellular adhesion molecule-1 expression following cerebral ischemia.

Hippocampal expression of apoptotic protease activating factor-1 following diffuse axonal injury under mild hypothermia

The influence of mild hypothermia on neural cell apoptosis remains poorly understood. Therefore, the present study established rat models of diffuse axonal injury （DAI） at 33℃. Morris water maze results demonstrated significantly better learning and memory functions in DAI rats with hypothermia compared with DAI rats with normothermia. Expression of apoptotic protease activating factor-1 in the hippocampal CA1 region was significantly lower in the DAI hypothermia group compared with the DAI normothermia group. Expression of apoptotic protease activating factor-1 positively correlated with latency, but negatively correlated with platform location times and time of swimming in the quadrant area. Results suggested that post-traumatic mild hypothermia in a rat model of DAI could provide cerebral protection by attenuating expression of apoptotic protease activating factor-1.

EFFECT OF MILD HYPOTHERMIA ON ACTIVITY NITRIC OXIDE SYNTHASE IN CORTICAL NEURONS AND GLYCEMIA LEVELS OF NEONATAL RATS WITH HYPOXIC ISCHEMIC BRAIN DAMAGE

Through investigating the effect of mild hypothermia on activity of nitric oxide snythase (NOS) in cortical neurons and glycemia levels of neonatal rats with hypoxic ischemic brain damage (HIBD). We studied the mechanism of protecting hypoxic ischemic neurons of mild hypothermia. We established neonatal rat HIBD models, used NOS immunohistochemistry and glycemia determination by micromethod. The number of cortical NOS positive neurons after hypoxic ischemia was significantly decreased as compared with controls. The glycemia levels was significantly increased than that controls. No significant difference was found in number of cortical NOS positive neurons and glycemia levels between 31℃ and 34℃ mild hypothemia. The results imply that hypothermia can decrease overproduction of NO through inhibiting the increase of the activity of NOS, and increase the glycemia levels, thus protect the hypoxic ischemic neurons.

Effect of mild hypothermia on glucose metabolism and glycerol of brain tissue in patients with severe traumatic brain injury

To study the effect of mild hypothermia on glucose metabolism and glycerol of brain tissue in patients with severe traumatic brain injury (sTBI).Methods All 33 patients with sTBI(GCS≤8) were randomly divided into hypothermic group and control group.Microdialysis catheters were inserted into the cerebral cortex of perilesion,relative normal brain tissue and subcutaneous tissue of abdomen in order to analyze the concentrations of lactate/pyruvate (L/P),lactate/glucose (L/G) and the glycerol(Gly) in extracellular fluid (ECF).Results In comparison with the control group,the concentration of L/G,L/P and Gly in periphery and that of L/P in ECF of the “normal brain tissue” were significantly decreased in the hypothermic group.In control group,concentration of L/G,L/P and Gly in periphery were higher than those in relative normal brain.In the hypothermic group,L/P concentration in periphery was higher than that in relative normal brain.Conclusion Mild hypothermia protects brain by decreasing concentrations of L/G,L/P and Gly in periphery and L/P concentration in “normal brain tissue”.The energy crisis and membrane phospholipid breakage in periphery are easier to happen after TBI,where mild hypothermia exerts significant protgective role.12 refs,3 tabs.

Effects of mild hypothermia on the ROS and expression of caspase-3 m RNA and LC3 of hippocampus nerve cells in rats after cardiopulmonary resuscitation

BACKGROUND: Cardiac arrest(CA) is a common and serious event in emergency medicine. Despite recent improvements in resuscitation techniques, the survival rate of patients with CA is unchanged. The present study was undertaken to observe the effect of mild hypothermia(MH) on the reactive oxygen species(ROS) and the effect of neurological function and related mechanisms.METHODS: Sixty-five healthy male Sprague Dawley(SD) adult rats were randomly(random number) divided into 2 groups: blank control group(n=5) and CPR group(n=60). CA was induced by asphyxia. The surviving rats were randomly(random number) divided into two groups: normothermia CPR group(NT) and hypothermia CPR group(HT). Normothermia of 37 °C was maintained in the NT group after return of spontaneous circulation(ROSC), hypothermal intervention of 32 °C was carried out in the HT group for 4 hours immediately after ROSC. Both the NT and HT groups were then randomly divided into 2 subgroups 12 hours and 24 hours after ROSC(NT-12, NT-24, HT-12, HT-24 subgroups). During observation, the neurological defi cit scores(NDSs) was recorded, then the bilateral hippocampi were obtained from rats' head, and monoplast suspension of fresh hippocampus tissue was made immediately to determine the level of intracellular ROS by flow cytometry. Transmission electron microscope was used to observe the ultramicro changes of cellular nucleus and mitochondria. Reverse transcription-polymerase chain reaction(RT-PCR) was used to determine the expression of caspase-3 m RNA, and western-blotting(WB) was used to determine the level of LC3 in frozen hippocampus tissue. Measured data were analyzed with paired sample t test and One-Way ANOVA.RESULTS: Of 60 rats with CA, 44(73%) were successfully resuscitated and 33(55%) survived until the end of the experiment. The NDSs of rats in the NT and HT groups were more signifi cantly reduced than those in the BC group(F=8.107, P<0.05), whereas the NDSs of rats in the HT-12 and HT-24 subgroups were significantly increased in comparison with those NDSs of rats in the NT-12 and NT-24 subgroups, respectively(t=9.692, P<0.001; t=14.374, P<0.001). The ROS in hippocampus nerve cells in the NT and HT groups signifi cantly increased compared to the BC group(F=16.824, P<0.05), whereas the ROS in the HT-12 and HT-24 subgroups significantly reduced compared with that ROS in the NT-12 and NT-24 subgroups, respectively(t=9.836, P<0.001; t=7.499, P<0.001). The expression of caspase-3 m RNA in hippocampus nerve cells in the NT and HT groups were signifi cantly increased compared to the BC group(F=24.527, P<0.05), whereas the expression of caspase-3 m RNA in rats of the HT-12 and HT-24 subgroups was signifi cantly reduced compared to the NT-12 and NT-24 subgroups, respectively(t=6.935, P<0.001; t=4.317, P<0.001). The expression of LC3B-II/I in hippocampus nerve cells of rats in the NT and HT groups signifi cantlyincreased compared to the BC group(F=6.584, P<0.05), whereas the expression of LC3B-II/I in rats of the HT-12 and HT-24 subgroups significantly reduced compared to the NT-12 and NT-24 subgroups, respectively(t=10.836, P<0.001; t=2.653, P=0.02). Ultrastructure damage of nucleus and mitochondria in the NT group was more evident than in the BC group, and eumorphism of nucleus and mitochondria were maintained in rats of the HT group compared with the NT group.CONCLUSION: Mild hypothermia lessened the injury of nerve cells and improved the neurological function of rats that survived from cardiac arrest by reducing the ROS production of nerve cells and inhibiting the expression of caspase-3 m RNA and LC3, leading to cellular apoptosis and massive autophagy in rats that survived from cardiac arrest after CPR.

Effects of immediate and delayed mild hypothermia on endogenous antioxidant enzymes and energy metabolites following global cerebral ischemia

Background The optimal time window for the administration of hypothermia following cerebral ischemia has been studied for decades, with disparity outcomes. In this study, the efficacy of mild brain hypothermia beginning at different time intervals on brain endogenous antioxidant enzyme and energy metabolites was investigated in a model of global cerebral ischemia. Methods Forty-eight male Sprague-Dawley rats were divided into a sham-operated group, a normothermia （37℃-38℃） ischemic group and a mild hypothermic （31℃-32℃） ischemia groups. Rats in the last group were subdivided into four groups： 240 minutes of hypothermia, 30 minutes of normothermia plus 210 minutes of hypothermia, 60 minutes of normothermia plus 180 minutes of hypothermia and 90 minutes of normothermia plus 150 minutes of hypothermia （n=8）. Global cerebral ischemia was established using the Pulsinelli four-vessel occlusion model for 20 minutes and mild hypothermia was applied after 20 minutes of ischemia. Brain.tissue was collected following 20 minutes of cerebral ischemia and 240 minutes of reperfusion, and used to measure the levels of superoxide dismutase （SOD）, glutathione peroxidase （GSH-Px）, reduced glutathione （GSH） and adenosine triphosphate （ATP）. Results Mild hypothermia that was started within 0 to 60 minutes delayed the consumption of SOD, GSH-Px, GSH, and ATP （P 〈0.05 or P 〈0.01） in ischemic tissue, as compared to a normothermic ischemia group. In contrast, mild hypothermia beginning at 90 minutes had little effect on the levels of SOD, GSH-Px, GSH, and ATP （P〉0.05）. Conclusions Postischemic mild brain hypothermia can significantly delay the consumption of endogenous antioxidant enzymes and energy metabolites, which are critical to the process of cerebral protection by mild hypothermia. These results show that mild hypothermia limits ischemic injury if started within 60 minutes, but loses its protective effects when delayed until 90 minutes following cerebral ischemia.

Efficacy of Mild Hypothermia for the Treatment of Patients with Cardiac Arrest

Background： Therapeutic hypothermia has been recommended for the treatment of cardiac arrest patients who remain comatose after the return of spontaneous circulation. The aim of this study was to evaluate the effectiveness and safety of mild hypothermia on patients with cardiac arrest by conducting a meta-analysis. Methods： The relevant trials were searched in Cochrane Library, PubMed, Web of Science, Embase, CNKI and Wan Fang Data from the date of their establishment to October 2014. Thereafter, the studies retrieved were screened based on predeflned inclusion and exclusion criteria. Data were extracted, and the quality of the included studies was evaluated. A meta-analysis was conducted using the Cochrane Collaboration Review Manager 5.2 sottware. Results： Six randomized controlled trials involving 531 cases were included, among which 273 cases were assigned to the treatment group and the other 258 cases to the control group. The meta-analysis indicated that mild hypothermia therapy alter cardiac arrest produced significant differences ill survival rate （relative risk [RR] =1.23, 95% confidence interval [C/]： 1.02-1.48, P = 0.03） and neurological function （RR - 1.33, 95% （.7： 1.08-1.65, P - 0.007） alter 6 months compared with normothermia therapy. However, no significant differences were observed in the survival to the hospital discharge （RR = 1.35, 95% CI： 0.87-2.10, P - 0.1 8）, favorable neurological outcome at hospital discharge （RR = 1.53, 95% CI： 0.95 2.45, P = 0.08） and adverse events. Conclusions： The meta-analysis demonstrated that mild hypothermia can improve the survival rate and neurological function of patients with cardiac arrest after 6 months. On the other hand, regarding the survival to hospital discharge, favorable neurological outcome at hospital discharge, and adverse events, our meta-analysis produced nonsignificant results.

Study on changes of partial pressure of brain tissue oxygen and brain temperature in acute phase of severe head injury during mild hypothermia therapy

Objective: To study the changes of partial pressure of brain tissue oxygen (PbtO 2) and brain temperature in acute phase of severe head injury during mild hypothermia therapy and the clinical significance. Methods: One hundred and sixteen patients with severe head injury were selected and divided into a mild hypothermia group (n=58), and a control group (n=58) according to odd and even numbers of hospitalization. While mild hypothermia therapy was performed PbtO 2 and brain temperature were monitored for 1 7 days (mean=86 hours), simultaneously, the intracranial pressure, rectum temperature, cerebral perfusion pressure, PaO 2 and PaCO 2 were also monitored. The patients were followed up for 6 months and the prognosis was evaluated with GOS (Glasgow outcome scale). Results: The mean value of PbtO 2 within 24 hour monitoring in the 116 patients was 13.7 mm Hg ± 4.94 mm Hg , lower than the normal value (16 mm Hg ± 40 mm Hg ) The time of PbtO 2 recovering to the normal value in the mild hypothermia group was shortened by 10± 4.15 hours compared with the control group (P< 0.05 ). The survival rate of the mild hypothermia group was 60.43 %, higher than that of the control group ( 46.55 %). After the recovery of the brain temperature, PbtO 2 increased with the rise of the brain temperature. Conclusions: Mild hypothermia can improve the survival rate of severe head injury. The technique of monitoring PbtO 2 and the brain temperature is safe and reliable, and has important clinical significance in judging disease condition and instructing clinical therapy.

Study of the effects of mild hypothermia on cerebral PO_2, PCO_2 and pH and body temperature in patients with acute severe head injury

Objective: To study the effects of mild hypothermia on cerebral oxygen partial pressure, carbon dioxide partial pressure, pH and body temperature （PbrO2, PbrCO2, pHbr and BT） in patients with acute severe head injury. Methods: Thirty-eight patients with acute severe head injury were treated with mild hypothermia, meantime PbrO2, PbrCO2, pHbr and BT were monitored in order to study the changes of PbrO2, PbrCO2, pHbr and BT. Results: In patients with acute head injury, mild hypothermia obviously increased PbrO2, decreased PbrCO2 and CO2 accumulation and acidosis in brain tissue. BT was 1℃-（1.5）℃ higher than rectal temperature（RT） after injury. The BT and RT were decreased when the patients were treated with mild hypothermia, but at the same time the difference between BT and RT was increased. Conclusions: In patients with acute severe head injury the direct monitoring of PbrO2, PbrCO2, pHbr and BT was safe and reliable, and is helpful in estimating prognosis and mild hypothermia therapy.

The effect of body weight on the induction of mild hypothermia in a rabbit model of asphyxia cardiac arrest

Objective To investigate the effect of body weight on the induction of mild hypothermia in a rabbit model of asphyxia cardiac arrest. Methods Twenty-four rabbits were randomized into two groups： the ice bag group and the intravenous 4℃ saline group. Cardiac arrest was induced and after 3 minutes of cardiac arrest, cardiopulmonary resuscitation was begun. Simultaneously, mild hypothermia was induced by putting an ice bag over the abdomen or infusion of 4℃ saline via an ear vein. A 2℃ decrease of rectal temperature was considered as the completion of hypothermia induction. Induction times were recorded, compared, and analyzed with respect to body weight. Results All rabbits had restoration of spontaneous circulation （ROSC） and ROSC lasted during the experiment. Induction time in the ice bag group was significantly shorter than that in the intravenous 4℃ saline group （22.8 ± 4.7 min VS 42.5 ± 4.0 min, P〈 0.001）. Induction time significantly correlated with body weight in the ice bag group （Pearson Correlation： r = 0.725, P = 0.029）, but not in the intravenous 4℃ saline group （Pearson Correlation： P = 0.418）. Conclusions In a rabbit model, induction of mild hypothermia with an ice bag is faster than with intravenous 4~C saline; induction time positively correlates with body weight when an ice bag is used, but not when intravenous 4℃ saline used. The effect of body weight should be considered when choosing an appropriate method to achieve early induction of mild hypothermia

Combination of mild therapeutic hypothermia and adipose-derived stem cells for ischemic brain injury

Mild therapeutic hypothermia has been shown to mitigate cerebral ischemia, reduce cerebral edema, and improve the prognosis of patients with cerebral ischemia. Adipose-derived stem cell-based therapy can decrease neuronal death and infiltration of inflammatory cells, exerting a neuroprotective effect. We hypothesized that the combination of mild therapeutic hypothermia and adipose-derived stem cells would be neuroprotective for treatment of stroke. A rat model of transient middle cerebral artery occlusion was established using the nylon monofilament method. Mild therapeutic hypothermia（33°C） was induced after 2 hours of ischemia. Adipose-derived stem cells were administered through the femoral vein during reperfusion. The severity of neurological dysfunction was measured by a modified Neurological Severity Score Scaling System. The area of the infarct lesion was determined by 2,3,5-triphenyltetrazolium chloride staining. Apoptotic neurons were detected by terminal deoxynucleotidyl transferase-mediated d UTP-biotin nick end labeling（TUNEL） staining. The regeneration of microvessels and changes in the glial scar were detected by immunofluorescence staining. The inflammatory responses after ischemic brain injury were evaluated by in situ staining using markers of inflammatory cells. The expression of inflammatory cytokines was measured by reverse transcription-polymerase chain reaction. Compared with mild therapeutic hypothermia or adipose-derived stem cell treatment alone, their combination substantially improved neurological deficits and decreased infarct size. They synergistically reduced the number of TUNEL-positive cells and glial fibrillary acidic protein expression, increased vascular endothelial growth factor levels, effectively reduced inflammatory cell infiltration and down-regulated the m RNA expression of the proinflammatory cytokines interleukin-1β, tumor necrosis factor-α and interleukin-6. Our findings indicate that combined treatment is a better approach for treating stroke compared with mild therapeutic hypothermia or adipose-derived stem cells alone.

不同时程亚低温治疗对重型颅脑损伤患者免疫功能及预后的影响

目的:分析对比不同时程亚低温治疗在重型颅脑损伤(STBI)患者中的效果。方法:选取2020年7月—2023年3月赣南医学院第一附属医院收治的120例STBI患者,按随机数字表法分为三组,各40例。常规组给予脱水、降颅压、去骨瓣减压术基础治疗,对照组在其基础上加以短时程(治疗2 d)亚低温治疗,观察组在常规组基础上加以长时程(治疗5 d)亚低温治疗。对比三组病情严重程度、免疫功能、氧合情况、并发症发生情况及预后。结果:治疗前,三组急性生理学和慢性健康状况评价Ⅱ(APACHEⅡ)评分、CD4^(+)、CD4^(+)/CD8^(+)、白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、γ干扰素(IFN-γ)、中心静脉血氧饱和度(ScvO_(2)),动-静脉二氧化碳分压差[P(cv-a)CO_(2)]相比,差异均无统计学意义(P>0.05);治疗后,观察组APACHEⅡ评分、IL-6、TNF-α、IFN-γ、P(cv-a)CO_(2)均低于对照组与常规组,CD4^(+)、CD4^(+)/CD8^(+)、ScvO_(2)均高于对照组与常规组,差异均有统计学意义(P<0.05);观察组、对照组并发症发生率、28 d死亡率均低于常规组,差异均有统计学意义(P<0.05);对照组、观察组并发症发生率、28 d死亡率相比,差异均无统计学意义(P>0.05)。结论:长时程亚低温治疗STBI患者效果更佳,可有效控制病情,改善其免疫功能,且并发症发生率与28 d死亡率更低,改善患者预后。