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Objective:To investigate the value of neutrophil-to-lymphocyte ratio (NLR) in predicting the prognosis of patients with severe heat stroke.Methods:A retrospective analysis was performed on patients with severe heat stroke hospitalized in the ICU of Changzhou No. 2 People's Hospital from June 2013 to September 2019. The patients were divided into the survival group and death group according to their 30-day survival. The basic data of the patients were recorded. Blood routine, liver and kidney function parameters, troponin, brain natriuretic peptide, myocardial enzyme spectrum, blood coagulation routine, and acute physiology and chronic health evaluation (APACHE)Ⅱ were analyzed within 24 h after admission. Multivariate COX regression analysis was used to screen the risk factors of 30-day death. Spearman correlation test was used to analyze the correlation between NLR and APACHEII score. Receiver operating characteristic (ROC) curves were drawn to assess the predictive value of NLR for the 30-day death in patients with severe heat stroke. Kaplan-Meier survival curve was used to analyze 30-day cumulative survival of high-risk patients.Results:A total of 115 patients with severe heat stroke were included in this study, and they were divided into the survival group ( n=92) and the death group ( n=23) according to the prognosis. NLR in the death group was significantly higher than that in the survival group ( P<0.05). Multivariate COX regression analysis showed that NLR was an independent risk factor for death after adjusting confounders ( HR=1.091, 95% CI: 1.049-1.136, P<0.001). Spearman correlation test showed a correlation between NLR and APACHEII score ( r=0.655, P<0.001). ROC curve analysis showed that NLR had the greatest predictive value for 30-day death, with an area under ROC curve (AUC) of 0.787, a sensitivity of 82.6%, a specificity of 67.4%, and the cut-off value of 7.35. Kaplan-Meier survival analysis curve shows that patients in the below NLR cut-off value group had a significantly higher 30-day survival rate than those in the above NLR cut-off value group ( P<0.001). Conclusions:The increased NLR is a high risk factor for death in patients with severe heat stroke, and helps predict the prognosis of patients with severe heat stroke.
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Objective:To observe whether endoplasmic reticulum stress and NOD-like receptor protein 3 (NLRP3) inflammasome activation were involved in severe heat stroke induced intestinal mucosal injury and to investigate the potential protective effect of the endoplasmic reticulum stress inhibitor 4-phenylbutyric acid (4-PBA).Methods:Thirty male BALB/c mice were randomly (random number) assigned to 3 groups: the control group, heat stroke group (HS), and 4-PBA pretreatment group (4-PBA+HS, 4-PBA 120 mg/kg, intraperitoneal injection). Mice in the control group were placed at room temperature, while mice in the HS group and 4-PBA+HS group were placed in a prewarmed chamber [temperature (35.5±0.5) °C, humidity (60.0±5.0)%]. A rectal temperature (Tc) that reached 42 °C was considered to indicate severe heat stroke. The concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) in intestinal homogenate were analyzed by a colorimetric method, serum interleukin-1β (IL-1β) and interleukin-18 (IL-18) were assessed by ELISA, intestinal histopathology was evaluated by hematoxylin and eosin (HE) staining, intestinal ultrastructure was observed by electron microscopy, and the protein expression of GRP78, CHOP, NLRP3 and cleaved caspase-1 were analyzed by Western blot. Data were statistically analyzed by ANOVA test and LSD- t multiple comparison test if homogeneous variance, or analyzed by Welch test and Dunnett's T3 multiple comparison test if heterogeneous variance. Results:The concentration of MDA in the HS group was increased ( t=14.243, P<0.01), while SOD was decreased compared with that in the control group ( t=7.781, P<0.01), and the concentrations of serum IL-1β and IL-18 were significantly elevated ( t=12.664, P<0.01; t=16.240, P<0.01). Under light microscopy, extensive destruction of small intestinal villi and inflammatory cell infiltration were observed in the intestines of mice with severe heat stroke. Transmission electron microscopy showed that endoplasmic reticulum structures were significantly expanded, and mitochondria were vacuolated in the intestines of mice with severe heat stroke. Compared with those in the control group, the protein expression levels of GRP78, CHOP, NLRP3 and cleaved caspase-1 in the small intestine were elevated in the HS group ( t=14.824, P <0.01; t=12.667, P<0.01; t=9.298, P<0.01; and t=6.588, P=0.001). Compared with those in the HS group, mice in the 4-PBA pretreatment group exhibited reduced concentrations of MDA ( t=9.167, P<0.01), increased SOD ( t=6.077, P<0.01) , and reduced serum IL-1β and IL-18 levels ( t=4.889, P= 0.001; t=5.693, P<0.01). In addition, 4-PBA pretreatment significantly alleviated the pathological disruption and ultrastructural damage to small intestine tissues. Moreover, 4-PBA pretreatment reduced GRP78, CHOP , NLRP3 and cleaved caspase-1 protein expression ( t=9.080, P<0.01; t=7.152, P<0.01; t=4.249, P=0.005; t=3.650, P=0.011). Conclusions:Endoplasmic reticulum stress and NLRP3 inflammasome are involved in intestinal mucosal injury induced by severe heat stroke. 4-PBA plays a protective role by alleviating endoplasmic reticulum stress and NLRP3 inflammasome activation.
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Objective:To explore the molecules mechanism of Pin1 in severe heat stroke induced acute lung injury by observing Pin1 regulate oxidative stress and apoptosis formation in pulmonary microvascular endothelial cells (PMVECs) and lung tissue in heat stressed mice.Methods:In vitro, a PMVECs heat stress (HS) model was established. In the control group, PMVECs were placed in a standard 37 °C, 5% CO 2 cell incubator; in the HS group, PMVECs were placed in a 43 °C cell incubator for 2 h, then the cells were further incubated at 37 °C for 1, 3, 6 or 12 h. PMVECs were pretreated with Pin1 inhibitor Juglone (1 μmol/L) 1 h before 43 °C of HS. In vivo, a severe heat stroke mouse model was established. In the HS group, the mice were kept at the simulation of climate chamber with temperature (35.5±0.5) °C, humidity (60±5)%, the rectum temperature in mice was measured by the anal rectal temperature table, when the temperature reached 42 °C, the heat exposure was stopped, and the mice were sacrificed at 1, 3, 6 or 12 h after HS. In the control group, the mice were kept at room temperature (25±0.5) °C. Mice received daily intraperitoneal administration of Pin1 inhibitor Juglone (1 mg/kg) for 3 d before HS. The protein level of Pin1, cleaved caspase-9 and cleaved caspase-3 were analyzed by Western blot, the level of O 2-˙ in cells was observed by DHE staining and fluorescence microscopy, the levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in lung tissue were measured by ELISA, the pathological changes of mice in different group were detected by HE staining, and the expression of Pin1 in the lung tissue of different groups was detected by immunohistochemical staining, the apoptosis rate of the lung tissue in different groups was tested by TUNEL staining. Results:At 1 h after HS, the protein expression of Pin1 in PMVECs and lung tissue began to increase in a rewarming time-dependent manner ( F=771.6, P<0.05; F=1 035, P<0.05). Cleaved caspase-9 protein in PMVECs and lung tissue started to increase at 3 h post-HS, then increased with a rewarming time-dependent manner ( F=729.8, P<0.05; F=1 773, P<0.05). The protein expression of cleaved caspase-3 in PMVECs and lung tissue also started to increase at 3 h after HS and the expression continued to be increased with prolonged rewarming time, and the trend was consistent with cleaved caspase-9 ( F=1 084, P<0.05; F=1 252, P<0.05). In addition, HS induced the increased release of O 2-˙ from PMVECs, HS induced the imbalance of oxidation-antioxidant system in lung tissue of mice after HS which verified by the continuous release of MDA ( F=114.2, P<0.05) and the continuous inhibition of SOD activity ( F=99.15, P<0.05). Compared with the HS group, pretreatment with Pin1 inhibitor Juglone in PMVECs and mice before HS significantly inhibited the protein expression of Pin1, cleaved caspase-9 and cleaved caspase-3 (all P<0.05), pretreatment with Pin1 inhibitor greatly reduced the release of O 2-˙ in PMVECs after HS, and promoted the restore of the oxidation-antioxidant system balance of lung tissue in mice with severe heat stroke. In addition, compared with the HS group, inhibiting the expression of Pin1 significantly decreased HS induced MDA release [(11.53±0.84) nmol/mL vs (9.65±0.69) nmol/mL, t=12.52, P<0.05], promoted the restore of SOD activity [(41.18±3.45) U/mL vs (57.52±4.83) U/mL, t=5.57, P<0.05] and improved the pathological damage of lung tissue as well as decreased the occurrence of apoptosis in post-HS mice. Conclusion:It was confirmed that Pin1 is involved in heat stress induced acute lung injury mainly through mediating oxidative stress response and apoptosis.
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Objective To explore the biological function of exosomes secrected by heat-stroke hepatocytes and its effect on liver injury. Methods Exosomes were isolated from donor HepG2 hepatocytes and control hepatocytes by ultra-high-speed centrifugation. The morphology of exosomes was observed by transmission electron microscopy, the diameter of distribution was detected by nano-tracking technology and the expression of characteristic surface markers CD9, CD63 and CD81 were examined by Western blotting. The isobaric tags for relative and absolute quantification methods were applied to analyze the difference in protein composition between the control and HS hepatocyte derived exosomes. Biological information analysis on the differential protein set was performed by the Kyoto Encyclopedia of Genes and Genomes pathway analysis. Recipient hepatocytes were stimulated with sterilized PBS, control hepatocyte exosomes or HS exosomes (10 μg for 24 h), or directly exposed to HS or pretreated with exosome production inhibitor GW4869 2 h before HS. Supernatant alanine aminotransferase (ALT)/aspartate aminotransferase (AST)/lactic dehydrogenase (LDH) levels tested for evaluation of the hepatocyte damage. C57/BL6 mice were injected with sterilized PBS, control hepatocyte exosomes or HS exosomes (40 μg/per mice) through the tail vein, or treated with HS or intraperitoneally injected with GW4869 2 h before HS and sacrificed 9 h thereafter. Plasma ALT/AST/LDH level was examined to assess liver tissue damage. Results The microparticles secreted by hepatocytes are round or elliptical structures with a double-layer membrane coating, with a diameter ranging from 90–150 nm and highly expressed CD9, CD63 and CD81, suggesting the consistence to exosomes. The number of exosomes released by HS hepatocytes was significantly elevated than that in the control group [(8.46±1.38)×109/ml vs. (0.66±0.16)×109/ml, t=5.605, P=0.005]. HS significantly altered the protein expression profile of hepatocyte exosomes, and the enriched proteins were involved in necroptosis, PI3K-Akt signaling, antigen processing and presentation, apoptosis and NOD-like receptor signaling pathways. The supernatant level of ALT/AST/LDH of the recipients' hepatocytes in the HS exosomes-treated group was significantly increased, whereas that in the HS+GW4869 pretreatment group was significantly lower than that in the HS group. The serum ALT/AST/LDH level of the HS exosomes infusion group was significantly enhanced, and that of the pre-HS GW4869 treatment group was significantly reduced than that of the HS group. Conclusion HS may induce the release of exosomes from hepatocytes, which may lead to the changes in the protein profile of exosomes and affect the induction of acute liver injury.
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Objective To observe the effects of Soyasaponins on inflammatory factors, antioxidant activity and exercise ability in rats with severe heat stroke. Methods Eighty male Sprague-Dawley (SD) rats were randomly divided into normal control group, heat shock model group, saline control group and Soyasaponin group, The rats that died during the experiment or with a low rectal temperature (< 41℃) were excluded, and finally 54 rats were included, 18 rats remaining in each group. The rats in the heat shock model group were placed in the simulated hot climate animal cabin at 30 ℃, and the temperature within 30 minutes was raised to 39 ℃ in the cabin with 65% humidity; in the mean time, the rat models of heat shock were replicated under the following situations: let the rats exercise on a treadmill with running speed set at 15 m/min, slope degree 0°, once running for 8 minutes, interval 2 minutes and the heat shock time was 90 minutes, the rats in the normal control group were fed in an environment with temperature ranging from 23-25 ℃ and relative humidity ranging from 50%-70%. After the establishment of models, the saline control group and Soyasaponin group were given daily saline and Soyasaponin (10 mg/kg) respectively by gavage for 3 consecutive months, while the heat shock model group was not given any treatment. The femoral artery blood was collected 24 hours after the rats left the cabin. The serum levels of interleukins (IL-6, IL-1β), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), malonaldehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) were measured by enzyme-linked immunosorbent (ELISA) and the contents of serum hemoglobin (Hb), serum urea (BUN), lactate dehydrogenase (LDH) and blood lactic acid (Lac) were measured by automatie biochemical analyzer. Results The levels of IL-6, IL-1β, TNF-α, IFN-γ, MDA, Hb, BUN, LDH, Lac in heat shock model group were significantly higher than those of the normal control group [IL-6 (ng/L): 86.17±4.82 vs. 12.60±3.49, IL-1β (ng/L): 83.00±5.98 vs. 15.70±3.64, TNF-α (ng/L): 72.22±6.93 vs. 13.75±2.69, IFN-γ (ng/L): 36.22±3.02 vs. 7.35±1.60, MDA (nmol/mg): 19.78±4.56 vs. 6.40±1.35, Hb (g/L): 136.22±1.93 vs. 126.75±5.84, BUN (mmol/L):21.06±3.44 vs. 5.65±1.35, LDH (μmoL·s-1·L-1): 9.65±0.83 vs. 2.12±0.17, Lac (mmol/L): 552.56±78.33 vs. 1.32±0.18, all P ＜ 0.05], SOD and GSH-Px were significantly lower than those in normal control group [SOD (kU/L):97.89±10.57 vs. 126.65±11.35, GSH-Px (kU/L): 19.22±2.58 vs. 43.45±4.02]; however, the levels of IL-6, IL-1β, TNF-α, IFN-γ, MDA, BUN, LDH and Lac in Soyasaponin group were significantly lower than those in heat shock model group [IL-6 (ng/L): 45.28±3.54 vs. 86.17±4.82, IL-1β (ng/L): 41.61±2.93 vs. 83.00±5.98, TNF-α (ng/L):37.22±2.46 vs. 72.22±6.93, IFN-γ (ng/L): 19.22±2.60 vs. 36.22±3.02, MDA (nmol/mg): 11.28±1.74 vs. 19.78±4.56, BUN (mmol/L): 11.78±2.13 vs. 21.06±3.44, LDH (μmoL·s-1·L-1): 3.70±0.26 vs. 9.65±0.83, Lac (mmol/L): 274.56±59.08 vs. 552.56±78.33, all P < 0.01], SOD, GSH-Px and Hb were significantly higher than those of heat shock model group [SOD (kU/L): 116.11±11.28 vs. 97.89±10.57, GSH-Px (kU/L): 31.17±2.90 vs. 19.22±2.58, Hb (g/L): 141.33±3.79 vs. 136.22±1.93, all P < 0.01]; there were no significant statistical differences in above indexes between heat shock model group and saline control group (all P > 0.05). Conclusion After heat shock and exercise management, the production and release of inflammatory factors are increased, and the level of lipid peroxidation was elevated in rats. The Soyasaponin can improve the ability to withstand heat shock and strong exercise by reducing the production and release of inflammatory factors and lipid peroxidation in the rats with severe heatstroke.
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Objective To explore the clinical application of combined cooling of Chinese and Western medicine on the cooling effect of patients with heatstroke. Methods A total of 80 patients with severe heat stroke admitted to the emergency department of our hospital from January 2016 to December 2017 were selected and divided into treatment group and control group according to the random number table method. 40 patients in the control group were given physical cooling. For conventional treatment, patients in the treatment group were given TCM treatment interventions on the basis of this, and clinical efficacy, changes in body temperature, and adverse screening events were compared between the two groups. Results The clinical effective rate (100.00%, ) in the treatment group was significantly higher than that in the control group (85.00%, Z=6.125,P<0.05). The duration of high fever, duration of fever, and recovery time of symptoms and signs were (0.57±0.46), (3.12±0.75), (7.25±3.18) h in the treatment group, (1.43±0.89), (5.37±0.63), (12.47± 4.53) h in the control group, there were significant differences between the two groups (t=5.429, 14.528, 5.965, P<0.05). After treatment, the levels of cTnl and CK-MB in the peripheral blood of the two groups decreased significantly (P<0.05). The levels of cTnl and CK-MB in peripheral blood of patients in the treatment group were (3.13±0.15) μg/L, (412.02±156.33) U/L, (3.54± 0.26) μg/L, (748.32±119.20) U/L in the control group, there were significant differences between the two groups (t=8.639, 10.819,P<0.05).There was no significant difference in the incidence of adverse reactions between the two groups (χ2=2.222, P=0.263). Conclusion The combination of Chinese and Western medicine physical cooling has a significant cooling effect on patients with heat stroke, and does not increase the risk of adverse reactions, it is worth clinical Promotion and application.
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With the global warming, the incidence of heat stroke was significantly higher than before. Severe heat stroke has a high mortality, high morbidity and consolidated central nervous system injury characteristics. The main features of severe heat stroke cerebral injury include cognitive impairment, delirium, convulsions and coma. Its mechanism is related with heat shock induced cerebral tissue ischemia and hypoxia, vascular dysfunction, secondary cascade inflammation and so on. Currently, the main treatment of heat stroke cerebral injury is the hypothermia therapy, dehydration for the reduction of intracranial pressure, naloxone and other cerebral protection and nutrition treatments. Hyperbaric oxygen therapy (HBOT) is effective in treating brain injury. HBOT can alleviate tissue ischemia and hypoxia, improve circulation, reduce cerebral edema, and anti-inflammatory, anti-oxidative damage, anti-apoptosis and other molecular biological effects. HBOT also play a wake up-promoting effect of nerve repair in the cerebral injury. The treatment of cerebral injury has been the difficulty and weakness of heat stroke research. Therefore, this article reviewed the epidemiology, pathogenesis, the therapeutic effect and mechanism of hyperbaric oxygen on cerebral injury in severe heat stroke to clarify the advantages of HBOT and to provide experimental basis for further research.
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Objective To observe the effect of different temperatures on endoplasmic reticulum stress, calcium overload, mitochondria and cell damage in pulmonary microvascular endothelial cells (PMVEC) induced by heat stress, and clarify the mechanism of endothelial cell injury in the process of heat stress to provide experimental basis for clinical prevention and treatment of heat stree. Methods Heat stress model of PMVEC cell was set up. Control group cells were incubated at 37℃, 5%CO2, while heat stress group cells were incubated at 39℃, 41℃, 43℃ for 2h, respectively, then further incubated at 37℃, 5%CO2 for 6h. Pretreatment of cells with 20μmol/L BAPTA-AM or 50μmol/L CsA before heat stress at 43℃. The protein levels of p-PERK, PERK p-eIF2a, eIF2a, ATF4 and GRP78 were analyzed by Western blotting. Intracellular Ca2+, mitochondrial membrane potential and the changes in mitochondrial permeability transition pore were investigated by flow cytometry. The change of caspase-3 was detected by Caspase Assay Kit. Millicell-ERS Volt-Ohm Meter and Accessories was used for determining the changes of transepithelium electrical resistance (TER). Results Compared with the control group, with the increase of heat stress temperature (41-43℃), the phosphorylation of p-PERK and p-eIF2a protein and the expressions of ATF4 and GRP78 proteins were gradually activated, intracellular Ca2+ increased, MPTP pore was opened, mitochondrial membrane potential decreased, cell permeability increased and apoptosis occurred, and it was the most obvious in the 43℃ heat stress group, and the difference was statistically significant (P<0.05). Pretreatment with Ca2+ inhibitors promoted the recovery of the MPTP hole, mitochondrial membrane potential and cell permeability, and reduced the occurrence of apoptosis. While pretreatment with the mitochondrial protective agent did not reduce the release of Ca2+, but it could promote the recovery of cell permeability and reduce the occurrence of apoptosis. Conclusion Heat stress activates endoplasmic reticulum stress response, induces intracellular Ca2+ overload mediated cell and mitochondrial damages in PMVEC cells, which may be one of the important mechanisms of endothelial cell injury induced by heat stress.
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ObjectiveTo study the effect of low molecular weight heparin sodium (LMWHS) therapy for exertional heat stroke (EHS) patients with pre-disseminated intravascular coagulation (pre-DIC).Methods A prospective randomized controlled trial (RCT) was conducted. Thirty-six patients with EHS with pre-DIC admitted to Department of Critical Care Medicine of 180th Hospital of Chinese PLA from April 2012 to November 2014 were divided into heparin sodium group (n = 20) and LMWHS group (n = 16) in accordance with the random number table. All patients received bundle treatment after being admitted to the hospital, including rapid cooling, fluid resuscitation, organ support (mechanical ventilation, hemopurification if necessary), supplement of pro-coagulation factors, etc. The patients in heparin sodium group were treated with continuous heparin sodium 12 500 U throughout 24 hours with intravenous pump for 5 days, and the patients in LMWHS group were given LMWHS 2 500 U subcutaneously, twice a day for 5 days.The incidence of DIC, incidence of bleeding and mortality of two groups were compared.The platelet count (PLT), prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fib) and D-dimer of each patient between pre and post treatment times were compared.Results No significant difference was found in the incidence of DIC and mortality between LMWHS group and heparin sodium group (31.2% vs. 30.0%,χ2 =0.007,P = 0.936; 6.2% vs. 5.0%,χ2 = 0.026,P = 0.871). Incidence of bleeding during treatment in LMWHS group was significantly lower than that in heparin sodium group (12.5% vs. 45.0%,χ2 = 4.425,P = 0.035). After treatment,PLT in both LMWHS group and heparin sodium group was significantly increased compared with that before treatment (×109/L: 140.5±17.5 vs. 110.5±16.5, 152.6±21.5 vs. 120.0±20.0, bothP 0.05). No significant difference was found in PT and Fib between pre and post treatment in all the patients.Conclusion When LMWHS was applied in EHS patients in pre-DIC stage, it could not only prevent DIC as efficiently as heparin sodium, but also results in lower incidence of bleeding. So LMWHS is safer.
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ObjectiveTo investigate the temporal features of renal injury in rats with severe heat stroke (SHS) and their relationship with inflammatory response.Methods Fifty-six male Wistar rats were randomly divided into normal control group and SHS for 0, 2, 6, 24, 48, 72 hours group (SHS-0, 2, 6, 24, 48, 72 h groups), with 8 rats in each group. Rats were placed in an artificial climate chamber [temperature (39.5±0.2)℃, humidity (60±5)%] to induce SHS model, and the criterion for successful model reproduction was the onset of lowering peak systolic blood pressure (SBP). Then the rats were transferred to room temperature (23.0±0.2)℃ after successful reproduction of the model. The rats of normal control group were kept in room temperature of (23.0±0.2)℃. Heart blood and renal tissue samples were harvested, and the levels of serum creatinine (SCr) and blood urea nitrogen (BUN) were determined by automatic biochemistry analyzer. The levels of myeloperoxidase (MPO), tumor necrosis factor-α(TNF-α) and interleukin-6 (IL-6) in renal tissue specimens were determined by enzyme linked immunosorbent assay (ELISA). The changes in histopathology in kidney were observed with light microscopy, and Paller scores were used to assess the degree of renal injury.Results Compared with normal control group, the levels of SCr and BUN in serum, and MPO, TNF-α and IL-6 in the renal tissue homogenate were significantly increased in SHS-6 h group [SCr (μmol/L): 174.0±27.0 vs.68.0±11.3, BUN (mmol/L): 12.6±2.3 vs. 4.3±1.2, MPO: (203.0±38.0)% vs. (100.0±1.4)%, TNF-α: (121.0±16.0)% vs. (100.0±1.4)%, IL-6: (118.0±19.0)% vs. (100.0±1.3)%, allP< 0.05], and they peaked at 24 hours [SCr (μmol/L): 489.0±96.0 vs. 68.0±11.3, BUN (mmol/L): 19.3±5.7 vs. 4.3±1.2, MPO: (511.0±41.0)% vs. (100.0± 1.4)%, TNF-α: (399.0±47.0)% vs. (100.0±1.4)%, IL-6: (473.0±56.0)% vs. (100.0±1.3)%, allP< 0.01], then declined to the normal levels at 72 hours. Under light microscopy, tissue edema and necrosis of renal tubules were found, and leukocyte infiltration was found to be most profuse at 24 hours, then they returned to normal levels at 72 hours. Paller scores in SHS-6 h group were significantly higher than those of the normal control group (75.45±9.70 vs. 14.23±3.26,P< 0.01), and it peaked at 24 hours (186.00±14.25 vs. 14.23±3.26,P< 0.01), followed by a gradual lowering, back to normal level at 72 hours.ConclusionThe results suggest that progressive renal damage occurred in the rats with SHS within 24 hours, and it was accompanied with elevated levels of MPO, TNF-α and IL-6 in the kidney homogenate, suggesting that inhibition of neutrophil activation and the release of IL-6, TNF-α may protect the SHS associated renal injury.
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Objective To observe the effect of heat stress-induced reactive oxygen species (ROS) burst on the regulation of expression of Bcl-2 and Bax in human umbilical vein endothelial cell (HUVEC) apoptosis induced by heat stress,and explore the pathogenesis of vascular endothelial damage caused by severe heat stroke.Methods HUVEC heat stress model was reproduced.Cells of heat stress group were incubated at either 39,41,or 43 ℃ for 2 hours,then all the cells were further incubated at 37 ℃ and 5％ CO2 for 24 hours.Before heat stress,cells of 43 ℃ heat stress group were pretreated with 10 μmol/L MnTMPyP,which was a specific scavenger of ROS,for 1 hour.Cells of control group were incubated at 37 ℃ and 5％ CO2.The amount of ROS was assayed with 2',7'-dichlorofluorescin diacetate (DCFH-DA) and dihydroethidium (DHE) staining.Apoptosis was determined by using staining with Hoechst33258.The mRNA expressions of Bcl-2 and Bax were determined by reverse transcription-polymerase chain reaction (RT-PCR).The protein levels of Bcl-2,Bax,caspase-3 were analyzed by Western Blot.In addition,the effect of MnTMPyP on heat stress-induced apoptosis was also studied.Results Compared with control group,there was no obvious change in cells after 39 ℃ heat stress.With the increase in heat stress temperature up to 41 ℃ and 43 ℃,viability of cells showed a lowering trend,with a burst of ROS,and an increase of mRNA and protein of Bax,and the protein of caspase-3 was significantly increased,the mRNA and protein of Bcl-2 were significantly decreased in a temperature-dependent manner.These changes were marked in 43 ℃ heat stress group as compared with those of the control group [cell viability:(46.00 ±4.00)％ vs.(96.33 ± 1.53)％,t=20.164,P=0.001; ROS (fluorescence relative value):400.67 ± 12.10 vs.99.33 ±4.04,t=32.909,P=0.001; Bax mRNA (A value):3.03 ±0.15 vs.1.00 ± 0.00,t=23.056,P=0.001; Bax protein (gray value):3.97 ±0.21 vs.1.00 ± 0.00,t=24.684,P=0.001; caspase-3 protein (gray value):4.80 ± 0.20 vs.1.00 ± 0.00,t=32.909,P=0.001 ; Bcl-2 mRNA(A value):0.42 ± 0.30 vs.1.00 ± 0.00,t=33.072,P=0.001 ; Bcl-2 protein (gray value):0.39 ± 0.25 vs.1.00 ± 0.00,t=42.212,P=0.001].It was shown that pre-condition with the antioxidant MnTMPyP significantly decreased the heat stress-induced expression of Bax,caspase-3,and apoptosis,and the expression of Bcl-2 was elevated [Bax mRNA (A value):2.00 ± 0.20 vs.3.33 ±0.25,t=7.184,P=0.002; Bax protein (gray value):2.03 ±0.25 vs.3.23 ±0.25,t=5.840,P=0.004; caspase-3 protein (gray value):2.07 ± 0.21 vs.5.00 ± 0.20,t=17.600,P=0.001 ; Bcl-2 mRNA(A value):0.71 ± 0.40 vs.0.42 ± 0.26,t=8.126,P=0.002; Bcl-2 protein (gray value):0.57 ± 0.31 vs.0.40 ± 0.06,t=5.091,P=0.007].Conclusions A burst in an increase of ROS plays an important role on heat stress-induced HUVEC apoptosis,and the mechanism is probably related to the expressions of Bcl-2 and Bax.The vascular endothelial cells apoptosis may be one of the pathogenetic factor in severe heat stroke.
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Objective To observe the effect of heat stress-induced burst out of reactive oxygen on neuronal apoptosis and investigate pathogenesis of brain damage caused by severe heat stroke.Methods Neurons heat stress model is set up.Control group were incubated at 37 ℃,5%CO2 ,While heat stress group of cells were incubated at 43 ℃for 2 h,then all the cells were further incubated at 37 ℃for different time as indicated.The amounts of ROS were assayed by DCFH staining at 0 h,0.5 h,1 h,2 h after heat stress.Apoptosis was analyzed by flow cytometry using Annexin V-FITC/PI staining and expression of caspase-3 were determined by westen blotat 0 h、3 h、6 h、12 h after heat stress.In addition,MnTMPyP is the specificscavengers of ROS,which effect on apoptosis is also studied at 12 h after heat stress.Results Compared with control group,amounts of ROS was significant increased at 0 h after heat stress,the burst out of it was at 2 h after heat stress (P<0.05 ).Apoptosis was induced at 3h after heat stress ,it was significant increased at 12 h after heat stress (43.2%,P<0.05 ).The expression of caspase-3 was also significant increased at 12 h after heat stress (P<0.05 ),and its trend was consistent with apoptosis rate trend.In addition,the scavengers MnTMPyP significantly decreased the apoptosis (47.42% to 18.45%, P<0.05 )and expression of caspase-3 at 12 h after heat stress.Conclusions An upstream signaling molecules,ROS could mediate heat stress-induced neuronal apoptosis,but its intermediate mechanism needs for further studies.