Objective:To develop and validate a Self-care Ability Scale for Arteriovenous Fistula (AVF) in Maintenance Hemodialysis (MHD) patients.Methods:Guided by Orem's self-care theory, the initial item pool of the scale was developed through a literature review, semi-structured interviews, and group discussions. The initial scale was finalized after two rounds of expert consultation using the Delphi method. A convenience sampling method was used to recruit 418 MHD patients using AVF in January 2024 for item analysis, exploratory factor analysis and reliability testing. Another 293 MHD patients using AVF were recruited in March 2024 for confirmatory factor analysis.Results:The self-care ability scale for AVF in MHD patients included four dimensions: knowledge and skills of AVF self-care, willingness and attitude toward AVF self-care, recognition and prevention of AVF complications, and patient self-adjustment and adaptation, comprising 38 items. The content validity index at the scale level was 0.98. Exploratory factor analysis extracted four common factors with a cumulative variance contribution rate of 84.706%. Confirmatory factor analysis indicated good model fit, strong convergent validity, and ideal discriminant validity. The total Cronbach's α coefficient of the scale was 0.987; the split-half reliability coefficient was 0.902, and the test-retest reliability coefficient was 0.979.Conclusions:The Self-care Ability Scale for AVF in MHD patients demonstrates excellent reliability and validity, making it a suitable tool for assessing patients' ability to self-care for their AVF.

Objective:To develop and validate a Self-care Ability Scale for Arteriovenous Fistula (AVF) in Maintenance Hemodialysis (MHD) patients.Methods:Guided by Orem's self-care theory, the initial item pool of the scale was developed through a literature review, semi-structured interviews, and group discussions. The initial scale was finalized after two rounds of expert consultation using the Delphi method. A convenience sampling method was used to recruit 418 MHD patients using AVF in January 2024 for item analysis, exploratory factor analysis and reliability testing. Another 293 MHD patients using AVF were recruited in March 2024 for confirmatory factor analysis.Results:The self-care ability scale for AVF in MHD patients included four dimensions: knowledge and skills of AVF self-care, willingness and attitude toward AVF self-care, recognition and prevention of AVF complications, and patient self-adjustment and adaptation, comprising 38 items. The content validity index at the scale level was 0.98. Exploratory factor analysis extracted four common factors with a cumulative variance contribution rate of 84.706%. Confirmatory factor analysis indicated good model fit, strong convergent validity, and ideal discriminant validity. The total Cronbach's α coefficient of the scale was 0.987; the split-half reliability coefficient was 0.902, and the test-retest reliability coefficient was 0.979.Conclusions:The Self-care Ability Scale for AVF in MHD patients demonstrates excellent reliability and validity, making it a suitable tool for assessing patients' ability to self-care for their AVF.

Objective To investigate the effect of vitamin B6(VB6)on vascular endothelial injury of atherosclerosis(AS)mice and its mechanism.Methods Thirty-six ApoE-/-mice were randomly divided into control group,AS group,VB6 group,AS+LiCl group,AS+VB6 group and AS+VB6+LiCl group,with 6 mice in each group.The mice in the AS group,AS+LiCl group,AS+VB6 group and AS+VB6+LiCl group were fed with high-fat diet for 12 weeks to establish the AS model;the mice in the control group and VB6 group were given regular diet and normal drinking water for 12 weeks.After 12 weeks,the mice in the control group were given conventional diet and the same volume of physiological saline as the VB6 group daily by gavage;the mice in the VB6 group were given routine diet and VB6(50 mg·kg-1)by gavage daily;the mice in the AS+LiCl group were given high-fat diet continuously and LiCl(1 mg·kg-1)by gavage daily;the mice in the AS+VB6 group were given high-fat diet continuously and VB6(50 mg·kg-1)by gavage daily;the mice in the AS+VB6+LiCl group were given high-fat diet continuously and VB6(50 mg·kg-1),LiCl(1 mg·kg-1)by gavage daily;all mice were intervened for 4 weeks.After intervention,the serum nitric oxide(NO),malondialdehyde(MD A)levels and superoxide dismutase(SOD)activity of mice in each group were measured by enzyme linked immunosorbent assay.Hematoxylin-eosin staining was used to observe the morphology of thoracic aortic tissue of mice in each group and the percentage of AS plaque area to total vascular area was calculated.The vasodilatation rate of thoracic aorta was detected by isolated vascular ring experiment.The expression of sodium/hydrogen exchanger 1(NHE1)protein in thoracic aorta was detected by immunohistochemistry.Results Compared with the control group,the NO level and SOD activity in the serum of mice in the AS group decreased,while the MDA level increased(P＜0.05);there was no significant difference in the NO,MDA levels and SOD activity in the serum of mice between the VB6 group and the control group(P＞0.05).Compared with the AS group,the serum NO level and SOD activity of mice in the AS+VB6 group increased,while the MDA level decreased(P＜0.05);there was no significant difference in serum NO,MDA levels and SOD activity of mice between the AS+LiCl group,AS+VB6+LiCl group and AS group(P＞0.05).Compared with the AS+VB6 group,the serum NO level and SOD activity of mice in the AS+VB6+LiCl group decreased,while the MDA level increased(P＜0.05).The percentage of AS plaque area to total vascular area of mice in the AS group was significantly higher than that in the control group(P＜0.05);there was no significant difference in the percentage of AS plaque area to total vascular area of mice among the VB6 group and the control group(P＜0.05).The percentage of AS plaque area to total vascular area of mice in the AS+VB6 group was significantly lower than that in the AS group(P＜0.05);there was no significant difference in the percentage of AS plaque area to total vascular area of mice between the AS+LiCl group,AS+VB6+LiCl group and AS group(P＜0.05).The percentage of AS plaque area to total vascular area of mice in the AS+VB6+LiCl group was significantly higher than that in the AS+VB6 group(P＜0.05).In the control group,the vascular endothelium of mice was smooth with orderly arrangement of cells;in the AS group,AS+LiCl group and AS+VB6+LiCl group,the tissue structure of vascular of mice was disordered and the vascular endothelium was rough;in the VB6 group and AS+VB6 group,the vascular wall structure of mice was normal,the vascular endothelium was smooth,and the cells were arranged orderly.The vasodilatation rate of thoracic aorta of mice induced by acetylcholine(Ach)in the AS group was significantly lower than that in the control group(P＜0.05);there was no significant difference in the vasodilatation rate of thoracic aorta of mice induced by Ach between the VB6 group and the control group(P＞0.05).The vasodilatation rate of thoracic aorta of mice induced by Ach in the AS+VB6 group was significantly lower than that in the AS group(P＜0.05);there was no significant difference in the vasodilatation rate of thoracic aorta of mice induced by Ach between AS+LiCl group,AS+VB6+LiCl group and AS group(P＞0.05).The vasodilatation rate of thoracic aorta of mice induced by Ach in the AS+VB6+LiCl group was significantly higher than that in the AS+VB6 group(P＜0.05).There was no significant difference in the vasodilatation rate of thoracic aorta of mice induced by sodium nitroprusside among the six groups(P＞0.05).The percentage of NHE1 expression in the thoracic aorta of mice in the AS group was significantly higher than that in the control group(P＜0.05);there was no significant difference in the percentage of NHE1 expression in the thoracic aorta of mice between the VB6 group and the control group(P＞0.05).The percentage of NHE1 expression in the thoracic aorta of mice in the AS+VB6 group was significantly lower than that in the AS group(P＜0.05);there was no significant difference in the percentage of NHE1 expression in the thoracic aorta of mice among the AS+LiCl group,AS+VB6+LiCl group and the AS group(P＞0.05).The percentage of NHE1 expression in the thoracic aorta of mice in the AS+VB6+LiCl group was significantly higher than that in the AS+VB6 group(P＜0.05).Conclusion VB6 can improve vascular endothelial injury in AS mice via inhibiting the expression of NHE1 protein.

Objective:To investigate the risk factors and their warning value for the occurrence of sepsis in patients with severe multiple trauma.Methods:A retrospective cohort study was conducted to analyze the clinical data of 92 patients with severe multiple trauma admitted to Yuyao People′s Hospital from July 2019 to October 2021. There were 71 males and 21 females, with the age range of 36-55 years [(45.5±13.6)years]. The injury severity score (ISS) was 20-29 points [(25.3±6.4)points]. The patients were divided into sepsis group ( n=32) and non-sepsis group ( n=60) according to whether sepsis occurred during hospitalization. Data were recorded for the two groups, including gender, age, basic diseases, cause of injury, number of injury sites, ISS, post-injury complications, and levels of aryl hydrocarbon receptor (AHR), C-reactive protein (CRP) and procalcitonin (PCT) at 1, 3 and 5 days after injury. The above data were analyzed to identify their correlation with the occurrence of sepsis in patients with severe multiple trauma by univariate analysis. The independent risk factors for sepsis in patients with severe multiple trauma were determined by multivariate Logistic regression analysis. The warning value of the single or combined risk factors for the occurrence of sepsis in patients with severe multiple trauma was evaluated by the receiver operating characteristic (ROC) curve and area under the curve (AUC). Results:By univariate analysis, it was demonstrated that the occurrence of sepsis was correlated with ISS, level of AHR at day 1 after injury, level of CRP at day 3 after injury and level of PCT at day 3 after injury ( P<0.05 or 0.01), but not with age, sex, basic diseases, level of AHR at 3, 5 days after injury, level of PCT at 1, 5 days after injury and level of CRP at 1, 5 days after injury (all P>0.05). By multivariate Logistic regression analysis, higher ISS ( OR=1.12, 95% CI 1.01, 1.24, P<0.05), level of AHR at day 1 after injury ( OR=1.30, 95% CI 1.10, 1.52, P<0.01) and level of PCT at day 3 after injury ( OR=1.81, 95% CI 1.08, 3.03, P<0.05) were found to be strongly correlated with the occurrence of sepsis. ROC curve analysis showed that higher ISS (AUC=0.69, 95% CI 0.57, 0.76) and level of AHR at day 1 after injury (AUC=0.79, 95% CI 0.68, 0.90) had warning value for the occurrence of sepsis, and the warning efficiency of combined panel was much better (AUC=0.86, 95% CI 0.77, 0.95). Conclusions:Higher ISS, level of AHR at day 1 after injury and level of PCT at day 3 after injury are independent risk factors for the occurrence of sepsis in patients with severe multiple trauma. ISS, AHR and combination of both exhibit good warning value for the occurrence of sepsis in patients with severe multiple trauma.

Objective To investigate the effects of therapeutic hypothermia (TH) on myocardial Ca2+/calmodulin-dependent protein kinase Ⅱ (CaMK Ⅱ) and cell autophagy after cardiopulmonary resuscitation (CPR) in swine.Methods Twenty healthy male domestic swine weighing 33-40 kg were randomly (random number) divided into 3 groups:sham group (n=4),CPR group (n=8) and TH group (n=8).Sham animals only underwent general preparation without experiencing cardiac arrest and resuscitation.The animal model was established by 8 min of electrically induced ventricular fibrillation and then 5 min CPR in the CPR and TH groups.Successful resuscitation was regarded as an organized rhythm with a mean arterial pressure of greater than 50 mmHg for 5 min or more.After successful resuscitation,body temperature was decreased to 33 ℃ by a cooling blanket and then maintained until 24 h post-resuscitation,and followed by a rewarming at a rate of 1 ℃/h for 5 h in the TH group.A normal temperature was maintained by the blanket throughout the experiment in the sham and CPR groups.At 6,12,24 and 30 h after resuscitation,the values of stroke volume (SV) and global ejection fraction (GEF) were measured by PiCCO,and meanwhile the serum concentrations of cardiac troponin Ⅰ (cTnI) were measured by ELISA assay and the serum activities of creatine kinase-MB (CK-MB) were evaluated by an automatic biochemical analyzer.At 30 h after resuscitation,the animals were sacrificed and left ventricular myocardium was obtained for the determination ofCaMK Ⅱ,microtubule-associated protein light chain 3 Ⅱ (LC3 Ⅱ) and p62 expressions by Western blot.The variables were compared with One way analysis of variance and then the Bonferroni test among the three groups.Results Compared with the sham group,myocardial dysfunction and injury after resuscitation were observed in the CPR and TH groups,which were indicated by decreased SV and GEF and also increased cTnI concentration and CK-MB activity in serum (all P＜0.05).Compared with the CPR group,the values of SV and GEF were significantly increased at 6 h after resuscitation,and serum cTnI concentration and CK-MB activity were significantly decreased starting 12 h after resuscitation in the TH group [SV (mL):25.0±6.9 vs 31.9±3.3 at 6 h,26.7±5.1 vs 34.6±3.7 at 12 h,28.8±3.3 vs 35.7±3.2 at 24 h,29.2±5.2 vs 36.7±3.3 at 30 h;GEF (％):17.1±2.7 vs 19.9±1.8 at 6 h,18.7±1.9 vs 21.6±1.8 at 12 h,19.3±2.3 vs 23.0±2.4 at 24 h,21.0±1.7 vs 23.7±1.7 at 30 h;cTnI (pg/mL):564±51 vs 466±56 at 12 h,534±38 vs 427±60 at 24 h,476±55 vs 375±46 at 30 h;CK-MB (U/L):803±164 vs 652±76 at 12 h,693±96 vs 557±54 at 24 h,633±91 vs 480±77 at 30 h,all P＜0.05].Tissue detection indicated that the expression of CaMK Ⅱ and LC3 Ⅱ were increased while the expression of p62 was decreased in post-resuscitation myocardium in the CPR and TH groups compared with the sham group (all P＜0.05).However,the expression of CaMK Ⅱ and LC3 Ⅱ were decreased and the expression of p62 was increased in postresuscitation myocardium in the TH group compared to the CPR group (CaMK Ⅱ:0.73±0.06 vs 0.58±0.05;LC3 Ⅱ:0.69±0.09 vs 0.50±0.07;p62:0.40±0.07 vs 0.68±0.14,all P＜0.05).Conclusion The mechanism of TH alleviating post-resuscitation myocardial dysfunction and injury may be related to the inhibition of CaMK Ⅱ expression and cell autophagy.

Objective To investigate the effects of dexmedetomidine postconditioning on brain injury after cardiac arrest and resuscitation in a swine model.Methods Twenty-eight healthy male domestic pigs,weighing 36±2 kg,were randomized (random number) into 4 groups (n=7 each group):sham operation group (S group),cardiopulmonary resuscitation group (CPR group),low-dose dexmedetomidine postconditioning group (LDP group),and high-dose dexmedetomidine postconditioning group (HDP group).Animals in the S group only underwent the surgical preparation.In the other three groups,the experimental model was established by 8 mins of electrically induced ventricular fibrillation and then 5 mins of cardiopulmonary resuscitation.At 5 min after resuscitation,a loading dose of dexmedetomidine of 0.25 μg/kg was intravenously infused followed by continuous infusion at a rate of 0.25 μg/(kg·h) for 6 h in the LDP group,and a loading dose of dexmedetomidine of 0.5 μ.g/kg was infused followed by continuous infusion at a rate of 0.5 μg/(kg·h) for 6 h in the HDP group.The same amount of normal saline was administered in the S and CPR groups.At 1 h,3 h,6 h and 24 h after resuscitation,the levels of serum neuron specific enolase (NSE) and S100B protein were measured.At 24 h after resuscitation,neurologic deficit score (NSD) was evaluated.After that,the animals were euthanized and cerebral cortex was obtained for the determination of tumor necrosis factor-α (TNF-α),interleukin-6 (IL-6)and malondialdehyde (MDA) contents,superoxide dismutase (SOD) activity,cell apoptosis and caspase-3 expression.Results Compared with the S group,post-resuscitation neurologic dysfunction and brain injury were observed in the other three groups,which were indicated by significantly higher NDS and markedly greater levels of serum NSE and S 100B (all P＜0.05).Compared with the CPR group,the score of NDS at 24 h post-resuscitation were significantly lower and the levels of serum NSE and S100B at 6 h and 24 h post-resuscitation were significantly less in the LDP and HDP groups [NDS:194±26,103±16 vs 278±23 at 24 h;NSE (ng/mL):32.4±1.8,28.6±3.7 vs 36.2±2.8 at 6 h,39.9±4.2,35.1±1.5 vs 45.1±3.0 at 24 h;S100B (pg/mL):2 534±207,2 382±170 vs 2 825±113 at 6 h,3 719±164,3 246±176 vs 4 085±161 at 24 h,all P＜0.05].Compared with the LDP group,neurologic dysfunction and brain injury at 24 h postresuscitation were further significantly alleviated in the HDP group (all P＜0.05).Pathological analysis indicated that brain inflammation,oxidative stress and cell apoptosis were observed after resuscitation in the CPR,LDP and HDP groups.However,the contents of TNF-α,IL-6 and MDA were significantly lower while the activity of SOD was significantly higher,and cell apoptosis and caspase-3 expression were significantly reduced in the brain after resuscitation in the LDP and HDP groups compared with the CPR group (all P＜0.05).In addition,those pathological injuries mentioned above were further significantly alleviated in the brain after resuscitation in the HDP group compared to the LDP group (all P＜0.05).Conclusions Dexmedetomidine postconditioning significantly alleviated the severity of postresuscitation brain injury in a dose-dependent manner,in which the protection was produced possibly through reducing tissue inflammation,oxidative stress and cell apoptosis.

Objective: To investigate the resuscitation effect of aortic balloon occlusion (ABO) on the traumatic cardiac arrest (TCA) in swine. Methods: Twenty-seven male domestic swine weighing (32.7±3.8)kg were utilized. After 40% of estimated blood volume was removed within 20 minutes, the animals were subjected to 5 minutes of untreated ventricular fibrillation and then 5 minutes of cardiopulmonary resuscitation. Additionally, fluid resuscitation was initiated coincident with the beginning of cardiopulmonary resuscitation. The animals were randomly divided into model group (n=12) and ABO group (n=15). Once cardiopulmonary resuscitation was implemented, aortic balloon was concurrently inflated to stop the blood flow of descending thoracic aorta at the level of the diaphragm in the ABO group. In the model group, aortic balloon was placed in the same position without inflation. During cardiopulmonary resuscitation, the changes of coronary perfusion pressure (CPP), forehead's regional cerebral oxygen saturation (rSO₂) and pressure of end-tidal CO₂ (PETCO₂) were continuously monitored, and the rate of return of spontaneous circulation (ROSC), duration of cardiopulmonary resuscitation, number of shocks and dose of epinephrine were recorded. At 5 minutes after successful resuscitation, the levels of arterial blood gas, lactate and jugular venous blood oxygen saturation (SjvO₂) were measured. Results: Compared with the model group, the values of CPP, rSO₂ and PETCO₂ during cardiopulmonary resuscitation were significantly increased in the ABO group [CPP: (33.5±5.6)mmHg vs. (23.1±5.2)mmHg at 1 minute, (35.3±6.0)mmHg vs. (26.8±7.4)mmHg at 2 minutes, (36.3±6.3)mmHg vs. (28.2±6.3)mmHg at 3 minutes, (40.1±7.1)mmHg vs. (30.5±6.2)mmHg at 4 minutes, (38.1±7.5)mmHg vs. (29.8±5.3)mmHg at 5 minutes; rSO₂: (45.4±5.2)% vs. (39.2±5.1)% at 1 minute, (47.2±3.6)% vs. (42.0±6.4)% at 2 minutes, (47.7±3.0)% vs. (41.5±5.4)% at 3 minutes, (47.0±2.5)% vs. (42.1±5.9)% at 4 minutes, (47.1±2.0)% vs. (41.5±7.4)% at 5 minutes; PETCO₂: (17.0±3.5)mmHg vs. (12.7±4.2)mmHg at 1 minute, (18.5±3.7)mmHg vs. (14.5±2.7)mmHg at 2 minutes, (20.7±5.3)mmHg vs. (15.5±3.2)mmHg at 3 minutes, (18.7±4.5)mmHg vs. (14.9±3.5)mmHg at 4 minutes, (18.2±3.2)mmHg vs. (14.5±4.2)mmHg at 5 minutes] (all P<0.05). The rate of ROSC was significantly higher in the ABO group than in the model group[100%(15/15) vs. 75%(9/12)] (P<0.05). Additionally, shorter duration of cardiopulmonary resuscitation, less number of shocks and lower doses of epinephrine were observed in the ABO group when compared with the model group[duration of cardiopulmonary resuscitation: 5(5, 5)minutes vs. 5(5, 12.5)minutes, number of shocks: 1(1, 1)times vs. 1(1, 4)times, dose of epinephrine: 0.62(0.62, 0.74)mg vs. 0.64(0.59, 2.59)mg] (all P<0.05). At 5 minutes after resuscitation, the level of arterial lactate was significantly decreased and the value of SjvO₂ was significantly increased in the ABO group compared with the model group[Lactate: (9.6±0.8)mmol/L vs. (10.8±1.4)mmol/L; SjvO₂: (50.0±8.6)% vs. (37.9±16.3)%] (both P<0.05). Conclusions In a swine model of TCA, ABO can increase cardiac and cerebral perfusion during cardiopulmonary resuscitation and improve the efficacy of cardiopulmonary resuscitation. It might provide a novel and effective method for the resuscitation of TCA in the clinical setting.

Objective To evaluate the effects of hypothermia on Ca2+∕calmodulin-dependent pro-tein kinase Ⅱ ( CaMKⅡ) and cell autophagy in brain tissues after cardiac arrest and cardiopulmonary re-suscitation ( CA-CPR) in swine. Methods Twenty-one healthy male white swine, weighing 33-40 kg, were divided into 3 groups using a random number table method: sham operation group ( group S, n=5) , CA-CPR group ( n=8) and hypothermia group ( group H, n=8) . The experimental model of CA-CPR was established in CA-CPR and H groups. The Swan-Ganz catheters were placed in the right femoral artery and vein to monitor the pressure of thoracic aorta and right atrium and body temperature and to collect blood sam-ples. A pacing catheter was advanced from the right external jugular vein into the right ventricle. Ventricu-lar fibrillation was induced by using a 1 mA alternating current through the pacing catheter. Once ventricular fibrillation was successfully induced, mechanical ventilation was discontinued for 8 min, and then CPR was initiated. Epinephrine 20 μg∕kg was intravenously injected at 2. 5 min of CPR, followed by repetition once every 3 min. Defibrillation was delivered at 5 min of CPR, and then spontaneous circulation was evaluated. If the spontaneous circulation was not restored, CPR was immediately resumed for 2 min, and then defibril-lation was delivered again. Mechanical ventilation was continued for 30 h after successful CPR. At 5 min af-ter successful resuscitation, body temperature was decreased to 33 ℃ by using a cooling blanket, then maintained at 33 ℃ until 24 h after resuscitation, and finally increased at a rate of 1℃∕h for 5 h in group H. The temperature was maintained at a normal level of 37. 5-38. 5 ℃ with the aid of a cooling blanket in S and CA-CPR groups. At 1, 6, 12, 24 and 30 h after resuscitation (T1-5), blood samples were collected from the femoral vein for measurement of the concentration of neuron specific enolase ( NSE) and S100βprotein in serum by enzyme-linked immunosorbent assay. Five animals in each group were then sacrificed, and brains were removed to determine the expression of CaMKⅡ, microtubule-associated protein 1 light chain 3 Ⅱ( LC3Ⅱ) and p62 in cerebral cortex by Western blot. Neurological deficit score was evaluated in the remaining three swine at 48, 72 and 96 h after resuscitation (T6-8) in CA-CPR and H groups. Results Compared with group S, the concentrations of NSE and S100β protein in serum were significantly in-creased at T1-5 , the expression of CaMKⅡand LC3Ⅱin cerebral cortex was up-regulated, and the expres-sion of p62 in cerebral cortex was down-regulated in CA-CPR and H groups (P<0. 05). Compared with group CA-CPR, the concentrations of NSE and S100βprotein in serum were significantly decreased at T3-5, the neurological deficit score was decreased at T6-8 , the expression of CaMKⅡand LC3Ⅱin cerebral cortex was down-regulated, and the expression of p62 in cerebral cortex was up-regulated in group H ( P<0. 05) . Conclusion The mechanism by which hypothermia alleviates brain injury after CA-CPR may be related to inhibiting CaMKⅡ activation and reducing cell autophagy in brain tissues of swine.

Objective To evaluate the effect of dexmedetomidine on receptor-interacting protein 1 (RIP1) signaling pathway during brain injury after cardiac arrest and resuscitation in pigs.Methods Twenty-one healthy domestic male white pigs,weighing 33-41 kg,were divided into 3 groups (n =7 each) using a random number table method:sham operation group (group S),cardiac arrest-resuscitation group (group CA-R) and dexmedetomidine group (group D).Ventricular fibrillation was electrically induced and untreated for 8 min followed by 5 min of cardiopulmonary resuscitation to establish the model of brain injury after cardiac arrest and resuscitation in anesthetized domestic white pigs.Dexmedetomidine was infused via the femoral vein in a loading dose of 0.5 μg/kg at 5 min after successful resuscitation,followed by an infusion of 0.5 μg · kg-1 · h-1 for 6 h in group D.The equal volume of normal saline was given instead in S and CA-R groups.The concentrations of neuron-specific endase (NSE) and S-100β protein in serum were measured at 1,3,6 and 24 h after resuscitation (T1-4).Neurologic deficit score (NDS) was evaluated at T4.The animals were sacrificed at T4,brains were removed and cerebral cortex tissues were obtained for determination of the expression of RIP1,RIP3 and mixed lineage kinase domain-like protein (MLKL) by Western blot.Results Compared with group S,the serum concentrations of NSE and S-100β protein were significantly increased at T1-4,the NDS was increased at T4,and the expression of RIP1,R1P3 and MLKL in cerebral cortex tissues was up-regulated in CA-R and D groups (P＜0.05).Compared with group CA-R,the serum concentrations of NSE and S-100β protein were significantly decreased at T3,4,the NDS was decreased at T4,and the expression of RIP1,RIP3 and MLKL in cerebral cortex tissues was down-regulated in group D (P＜0.05).Conclusion The mechanism by which dexmedetomidine reduces brain injury after cardiac arrest and resuscitation may be related to inhibiting the activation of RIP 1 signaling pathway in pigs.

Objective To evaluate the effect of mild hypothermia on inositol-requiring enzyme 1 (IRE1) signaling pathway during myocardial injury after cardiac arrest and resuscitation in swine.Methods Twenty-one healthy male white swine,weighing 33-41 kg,were divided into 3 groups using a random number table method:sham operation group (group S,n =5),cardiac arrest-cardiopulmonary resuscitation group (group CA-CPR,n=8),and mild hypothermia group (group MH,n=8).The model of cardiac arrest and resuscitation was established based on the previously reported method.The catheters placed in the left femoral artery and right internal jugular vein were connected to the PiCCO Monitor system,and another pacing catheter was advanced from the right external jugular vein into the right ventricle.Ventricular fibrillation was induced by using a 1 mA alternating current through the pacing catheter.Once ventricular fibrillation was successfully induced,mechanical ventilation was discontinued for 8 min,and then cardiopulmonary resuscitation was initiated.Epinephrine 20 μg/kg was administered at 2.5 min of resuscitation followed by repetition every 3 min.Defibrillation was delivered at 5 min of resuscitation,and then spontaneous circulation was evaluated.If return of spontaneous circulation was not achieved,cardiopulmonary resuscitation was immediately resumed for 2 min and then defibrillation was delivered again.Mechanical ventilation was continued for 30 h after successful resuscitation.Animals in group S only underwent surgical preparation without experiencing cardiac arrest and resuscitation.At 5 min after successful resuscitation,body temperature was cooled down to 33 ℃ by using a cooling blanket,and then maintained at this level until 24 h after resuscitation,followed by 5 h of re-warming at a rate of 1 ℃/h in group MH.The temperature was maintained at 37.5-38.5 ℃ with the aid of surface cooling blanket in the other two groups.At 1,6,12,24 and 30 h after resuscitation (T1-5),the values of stroke volume (SV) and global ejection fraction (GEF) were recorded,and meanwhile 2 ml of blood samples was obtained via the femoral vein to measure the concentration of serum cardiac troponin Ⅰ (cTnI) (by enzyme-linked immunosorbent assay) and activity of serum creatine kinase-MB (CK-MB) (by immunosuppression).The swine were sacrificed at 30 h after resuscitation,and then myocardial specimens from the left ventricle were obtained for determination of the expression of caspase-3 (by immunohistochemistry),cell apoptosis (by TUNEL),and expression of IRE1 and casepase-12 (by Western blot).Apoptosis index was calculated.Results Compared with group S,SV and GEF were significantly decreased and the serum CK-MB activity was increased at T1-5,the concentration of serum cTnI was increased at T2-5,the expression of IRE1,caspase-12 and caspase-3 in myocardium was up-regulated,and apoptosis index was increased in CA-CPR and MH groups (P＜0.05).Compared with group CA-CPR,the SV and GEF were significantly increased and the concentration of serum cTnI was decreased at T2-5,the activity of serum CK-MB was decreased at T3-5,the expression of IRE1,caspase-12 and caspase-3 in myocardium was down-regulated,and apoptosis index was decreased in group MH (P＜0.05).Conclusion The mechanism by which mild hypothermia mitigates myocardial injury after cardiac arrest and resuscitation may be related to inhibiting IRE1 signaling pathway in swine.