The tumor microenvironment (TME) is a critical determinant of tumor initiation, progression, and therapeutic response, and serves as the basis for designing precise delivery strategies. Its marked heterogeneity underscores the need for a more comprehensive understanding of its composition and function. In addition to the extensively studied classical TME, emerging evidence highlights the significant roles of the tumor mechanical microenvironment and the tumor microbial microenvironment in modulating treatment efficacy. These non-classical dimensions not only independently influence tumor behavior but also interact dynamically with classical TME components. Mechanical cues within the TME, including matrix stiffness and solid stress, significantly affect drug distribution and treatment efficacy, suggesting that mechanical remodeling represents a potential strategy to enhance therapeutic outcomes. Concurrently, tumor-associated microbiota and their metabolites participate in immune regulation and metabolic reprogramming, contributing to tumor development and offering novel therapeutic targets. Moreover, recent advances have broadened our understanding on the multilayered regulatory landscape of the TME through the investigation of previously underappreciated factors such as neural regulation, metabolic niche dynamics, spatiotemporal heterogeneity, and epigenetic modulation. This review systematically summarizes the characteristics of these diverse TME dimensions and highlights recent progress in targeted delivery strategies, to facilitate the development of more personalized and effective anticancer therapies.
Humans ; Tumor Microenvironment ; Neoplasms/pathology* ; Drug Delivery Systems ; Antineoplastic Agents/administration & dosage*

Objective:To investigate the correlation between serum neuron-specific enolase (NSE) levels and poor neurological outcomes in cardiac arrest (CA) patients supported by veno-arterial extracorporeal membrane oxygenation (VA-ECMO).Methods:This retrospective analysis was conducted on adult CA patients treated with VA-ECMO at Hangzhou First People's Hospital Affiliated to Westlake University School of Medicine, and Second Affiliated Hospital Zhejiang University School of Medicine, from December 2018 to February 2024. General clinical data and serial serum NSE levels at 24, 48, and 72 h after ECMO initiation were collected. Based on the Glasgow-Pittsburgh Cerebral Performance Category (CPC) at discharge, patients were divided into poor neurological outcome group (CPC 3-5) and good neurological outcome group (CPC 1-2). Differences in serum NSE levels between the two groups were compared. The accuracy of serum NSE levels at three time points in predicting poor neurological outcomes in CA patients was assessed via receiver operating characteristic curves, and the optimal cut-off values were determined by the Youden index. Multivariate logistic regression analysis was performed to determine the relationship between serum NSE levels and poor neurological outcomes. Subgroup analysis was based on age, sex, location of CA, and extracorporeal cardiopulmonary resuscitation (ECPR).Results:A total of 120 eligible CA patients were included, with 88 patients (73.3%) having poor neurological outcomes at discharge. Serum NSE levels at 24, 48, and 72 h after ECMO initiation were higher in the poor outcome group compared to the good outcome group (all P<0.05). The serum NSE level at 72 h had the highest accuracy in predicting poor outcomes, with an area under the curve (AUC) of 0.91 (95% CI: 0.85-0.96), and a cut-off value of 42.0 μg/L. The AUCs for 24 and 48 h were 0.78 (95% CI: 0.69-0.86) and 0.87 (95% CI: 0.80-0.94), with cut-off values of 70.6 μg/L and 64.5 μg/L, respectively. Multivariate logistic regression analysis suggested that the serum NSE level at 72 h was associated with poor outcomes ( P<0.05), and an NSE level >42.0 μg/L was an independent risk factor for poor outcomes ( OR=20.29, 95% CI: 2.90-92.15). Subgroup analysis showed that serum NSE level at 72 h was an independent risk factor for poor neurological outcomes in CA patients aged<60 years old, male or female, out-of-hospital or in-hospital CA, and whether to perform ECPR (all P<0.05). Conclusion:Elevated serum NSE levels at 72 h after VA-ECMO initiation are associated with poor neurological outcomes in CA patients, with the cut-off value of 42.0 μg/L.

Objective:To investigate the efficacy of a domestically developed small esophageal cooling device in implementing targeted temperature management (TTM) after resuscitation and its impact on organ injury using a porcine model of cardiac arrest and resuscitation.Methods:Thirty healthy male domestic white pigs were randomly divided into four groups using a random number table: sham (S group, n=6), normothermia (NT group, n=8), surface cooling (SC group, n=8), and esophageal cooling (EC group, n=8). The S group underwent only surgical preparation, while the other groups were subjected to 12 minutes of ventricular fibrillation followed by 6 minutes of cardiopulmonary resuscitation to establish cardiac arrest. The S and NT groups maintained a core temperature of (37.5±0.5)°C using a surface blanket. In the SC and EC groups, therapeutic hypothermia was induced post-resuscitation via surface blanket or esophageal cooling catheter to achieve a target temperature of 34°C, maintained the target temperature (34±0.5)°C for 6 hours, followed by controlled rewarming at 0.5°C/h to 37°C. Core temperature was continuously monitored for 12 hours post-resuscitation. Hemodynamic parameters, including stroke volume (SV), global ejection fraction (GEF), extravascular lung water index (ELWI), and pulmonary vascular permeability index (PVPI), were assessed using pulse indicator continuous cardiac output (PiCCO) monitoring. Serum levels of cardiac troponin I (cTnI), neuron-specific enolase (NSE), creatinine (Cr), and intestinal fatty acid-binding protein (IFABP) were measured via ELISA at 2, 6, 12, and 24 hours post-resuscitation. Neurological outcomes were evaluated at 24 hours using the neurological deficit score (NDS) and cerebral performance category (CPC). Continuous variables were analyzed using one-way ANOVA. Results:During TTM, the EC group exhibited a faster cooling rate [(1.52±0.18)°C/h vs. (0.94±0.32)°C/h, P<0.05] and shorter time to target temperature [(2.32±0.43) h vs. (3.78±0.82) h, P<0.05] compared to the SC group, with comparable maintenance and rewarming ( P>0.05). Compared to the S group, the NT, SC, and EC groups demonstrated significant post-resuscitation multi-organ injury, characterized by reduced SV and GEF, elevated ELWI and PVPI, and increased serum cTnI, NSE, Cr, IFABP, NDS, and CPC scores (all P<0.05). Relative to the NT group, the SC and EC groups showed improved SV (at 1 h post-resuscitation), GEF (at 1, 2, 4, and 6 h), ELWI (at 12 h), and reduced cTnI and NSE (at 6 h), Cr and IFABP (at 2 h), and NDS and CPC (at 24 h) (all P<0.05). Compared to the SC group, the EC group exhibited lower PVPI (at 12 h), reduced cTnI, Cr, and IFABP (at 2 h), decreased NSE (at 2, 12, and 24 h), and improved NDS (at 24 h) (all P<0.05). Conclusions:In a porcine model of cardiac arrest and resuscitation, the domestic esophageal cooling device facilitated rapid induction, stable maintenance, and controlled rewarming during TTM, outperforming traditional surface cooling. This approach demonstrated superior organ protection, warranting further investigation.

Objective:To evaluate the effect of tubastatin A (TubA) on pyroptosis during brain injury after cardiac arrest and resuscitation in swine.Methods:Twenty-two conventional male white swine, weighing 34-39 kg, aged 4-6 months, were divided into 3 groups using a random number table: sham operation group (group S, n=6), cardiac arrest-cardiopulmonary resuscitation (CA-CPR) group ( n=8) and CA-CPR+ TubA group ( n=8). The swine model of CA-CPR was established by 9 min of cardiac arrest and 6 min of cardiopulmonary resuscitation in CA-CPR group and CA-CPR+ TubA group. TubA 4.5 mg/kg (in 50 ml of normal saline) was infused over 1 h via the femoral vein starting from 5 min after resuscitation in CA-CPR+ TubA group. Before developing the model and at 1, 2, 4 and 24 h after resuscitation (T 0-4), blood samples were collected from the femoral vein for determination of the concentrations of neuron specific enolase (NSE) and S100β protein in serum (by enzyme-linked immunosorbent assay). Neurological deficit score (NDS) was evaluated at T 4. The animals were then sacrificed, and their brain cortex tissues were harvested to measure the expression of histone deacetylase 6 (HDAC6), caspase-3, cleaved caspase-3, gasdermin E (GSDME) and GSDME N-terminal (N-GSDME) (by Western blot) and contents of high mobility group box 1 (HMGB1), interleukin-1β (IL-1β) and IL-18 (by enzyme-linked immunosorbent assay). Results:Compared with group S, the serum concentrations of NSE and S100β were significantly increased at T 1-4, NDS was increased at T 4, the expression of HDAC6, caspase-3, cleaved caspase-3, GSDME and N-GSDME in brain cortex was up-regulated, and the contents of HMGB1, IL-1β and IL-18 were increased in CA-CPR and CA-CPR+ TubA groups ( P<0.05). Compared with group CA-CPR, the serum concentrations of NSE and S100β were significantly decreased at T 3, 4, NDS was decreased at T 4, the expression of HDAC6, caspase-3, cleaved caspase-3, GSDME and N-GSDME in brain cortex was down-regulated, and the contents of HMGB1, IL-1β and IL-18 were decreased in group CA-CPR+ TubA ( P<0.05). Conclusions:The mechanism by which TubA alleviates brain injury after cardiac arrest and resuscitation may be related to inhibition of pyroptosis in swine.

Objective:To explore the protective efficacy of sulforaphane (SFN) in alleviating intestinal mucosal injury after resuscitation in pigs and its possible mechanism.Methods:This experiment was performed in the laboratory animal center, Zhejiang university. Using a random number table, twenty-four domestic healthy male white pigs were randomly divided into the Sham group, cardiopulmonary resuscitation (CPR) group, and SFN group, in which the Sham group had 6 pigs, and the other two groups had 9 pigs, respectively. The experimental parameters of 10 min of cardiac arrest and 6 min of CPR were chosen to establish the porcine model of CPR in the CPR and SFN groups. At 5 min after resuscitation, a dose of 2 mg/kg of SFN was infused via the femoral vein within 10 min in the SFN group. At 1 h, 2 h, 4 h, and 24 h after resuscitation, vein samples were collected, and then the levels of intestinal fatty acid binding protein (IFABP) and diamine oxidase (DAO) in serum were measured by ELISA. Subsequently, 6 pigs were chosen to be euthanized in each group, and then tissue samples were harvested from distal ileum to measure the level of cell apoptosis by TUNEL, the activities of superoxide dismutase (SOD) and catalase (CAT) and the contents of glutathione (GSH) and malondialdehyde (MDA) by biochemical method, the contents of 4-hydroxy-2-nonenal (4-HNE) by ELISA, the fluorescence intensity of reactive oxygen species (ROS) by immunofluorescence staining, and the expression levels of zonula occluden-1 (ZO-1), occludin, nuclear factor E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) by Western blot. Continuous variables were compared with one way analysis of variance among the three groups, and Bonferroni test was used for further pairwise comparison.Results:During the observation period after resuscitation, the serum levels of biomarkers of intestinal mucosal injury including IFABP and DAO were significantly higher in the CPR and SFN groups than in the Sham group (all P<0.05). However, the serum levels of IFABP at 2 h, 4 h, and 24 h after resuscitation and the serum levels of DAO at 1 h, 2 h, 4 h, and 24 h after resuscitation were significantly lower in the SFN group than in the CPR group (all P<0.05). At 24 h after resuscitation, apoptotic index was significantly increased, SOD and CAT activities and GSH contents were significantly decreased, MDA and 4-HNE contents and ROS production were significantly increased, ZO-1 and occludin expression were significantly down-regulated, and Nrf2 and HO-1 expression were significantly up-regulated in the CPR and SFN groups when compared with the Sham group (all P<0.05). However, apoptotic index was significantly decreased, SOD and CAT activities and GSH contents were significantly increased, MDA and 4-HNE contents and ROS production were significantly decreased, and ZO-1, occludin, Nrf2, and HO-1 expression were significantly up-regulated in the SFN group when compared to the CPR group (all P<0.05). Conclusion:SFN could effectively protect against intestinal mucosal injury after resuscitation in pigs, and its mechanism was possibly related to the inhibition of oxidative stress and cell apoptosis via the activation of Nrf2/HO-1 pathway.

OBJECTIVE: To investigate the protective effect and potential mechanism of tubastatin A (TubA), a specific inhibitor of histone deacetylase 6 (HDAC6), on renal and intestinal injuries after cardiopulmonary resuscitation (CPR) in swine. METHODS: Twenty-five healthy male white swine were divided into Sham group (n = 6), CPR model group (n = 10) and TubA intervention group (n = 9) using a random number table. The porcine model of CPR was reproduced by 9-minute cardiac arrest induced by electrical stimulation via right ventricle followed by 6-minute CPR. The animals in the Sham group only underwent the regular operation including endotracheal intubation, catheterization, and anesthetic monitoring. At 5 minutes after successful resuscitation, a dose of 4.5 mg/kg of TubA was infused via the femoral vein within 1 hour in the TubA intervention group. The same volume of normal saline was infused in the Sham and CPR model groups. Venous samples were collected before modeling and 1, 2, 4, 24 hours after resuscitation, and the levels of serum creatinine (SCr), blood urea nitrogen (BUN), intestinal fatty acid binding protein (I-FABP) and diamine oxidase (DAO) in serum were determined by enzyme-linked immunoadsordent assay (ELISA). At 24 hours after resuscitation, the upper pole of left kidney and terminal ileum were harvested to detect cell apoptosis by TdT-mediated dUTP-biotin nick end labeling (TUNEL), and the expression levels of receptor-interacting protein 3 (RIP3) and mixed lineage kinase domain-like protein (MLKL) were detected by Western blotting. RESULTS: After resuscitation, renal dysfunction and intestinal mucous injury were observed in the CPR model and TubA intervention groups when compared with the Sham group, which was indicated by significantly increased levels of SCr, BUN, I-FABP and DAO in serum. However, the serum levels of SCr and DAO starting 1 hour after resuscitation, the serum levels of BUN starting 2 hours after resuscitation, and the serum levels of I-FABP starting 4 hours after resuscitation were significantly decreased in the TubA intervention group when compared with the CPR model group [1-hour SCr (μmol/L): 87±6 vs. 122±7, 1-hour DAO (kU/L): 8.1±1.2 vs. 10.3±0.8, 2-hour BUN (mmol/L): 12.3±1.2 vs. 14.7±1.3, 4-hour I-FABP (ng/L): 661±39 vs. 751±38, all P < 0.05]. The detection of tissue samples indicated that cell apoptosis and necroptosis in the kidney and intestine at 24 hours after resuscitation were significantly greater in the CPR model and TubA intervention groups when compared with the Sham group, which were indicated by significantly increased apoptotic index and markedly elevated expression levels of RIP3 and MLKL. Nevertheless, compared with the CPR model group, renal and intestinal apoptotic indexes at 24 hours after resuscitation in the TubA intervention group were significantly decreased [renal apoptosis index: (21.4±4.6)% vs. (55.2±9.5)%, intestinal apoptosis index: (21.3±4.5)% vs. (50.9±7.0)%, both P < 0.05], and the expression levels of RIP3 and MLKL were significantly reduced [renal tissue: RIP3 protein (RIP3/GAPDH) was 1.11±0.07 vs. 1.39±0.17, MLKL protein (MLKL/GAPDH) was 1.20±0.14 vs. 1.51±0.26; intestinal tissue: RIP3 protein (RIP3/GAPDH) was 1.24±0.18 vs. 1.69±0.28, MLKL protein (MLKL/GAPDH) was 1.38±0.15 vs. 1.80±0.26, all P < 0.05]. CONCLUSIONS TubA has the protective effect on alleviating post-resuscitation renal dysfunction and intestinal mucous injury, and its mechanism may be related to inhibition of cell apoptosis and necroptosis.
Male ; Animals ; Swine ; Abdominal Injuries ; Apoptosis ; Cardiopulmonary Resuscitation ; Kidney Diseases

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 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 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.