Role of SIRT1 in mitochondrial dysfunction in mice with lipopolysaccharide-induced brain injury / 中华麻醉学杂志

Objective:To evaluate the role of silent information regulator sirtuin 1 (SIRT1) in mitochondrial dysfunction in mice with lipopolysaccharide (LPS)-induced brain injury.Methods:Eighty clean-grade male C57BL/6 mice, aged 6-8 weeks, were divided into 4 groups ( n=20 each) by the random number table method: control group (group C), LPS-induced brain injury group (LPS group), LPS-induced brain injury plus SIRT1 inhibitor EX527 group (LPS+ E group), and LPS-induced brain injury plus SIRT1 agonist SRT1720 group (LPS+ S group). Brain injury was induced by intravenous injection of LPS 10 mg/kg. EX527 10 mg/kg was intraperitoneally injected at 72 h before LPS injection in group LPS+ E, and the equal volume of dimethyl sulfoxide was intraperitoneally injected instead in the other three groups. SRT1720 100 mg/kg was intraperitoneally injected at 30 min before LPS injection in group LPS+ S, and the equal volume of dimethyl sulfoxide was intraperitoneally injected instead in the other three groups. The novel object recognition test was performed at 24 h after LPS injection, then the mice were sacrificed, and hippocampal tissues were harvested for determination of the number of the normal neurons in the hippocampal CA1 area, ATP content and activities of mitochondrial respiratory chain complexes Ⅰ, Ⅱ, Ⅲ and Ⅳ (by spectrophotometry), and mitochondrial membrane potential (MMP) (by Jc-1 staining) and for microscopic examination of pathological changes (by Nissl staining) and ultrastructure of neuronal mitochondria (with a transmission electron microscope). Results:Compared with group C, the preference index in novel object recognition, normal neuron count, activities of mitochondrial respiratory chain complexes Ⅰ, Ⅱ, Ⅲ and Ⅳ, MMP and ATP content were significantly decreased ( P<0.05), damage to hippocampal neurons was found, mitochondrial swelling was observed and cristae structure ruptured in LPS, LPS+ S and LPS+ E groups. Compared with group LPS, the preference index in novel object recognition, activities of mitochondrial respiratory chain complexes, MMP and ATP content were significantly decreased ( P<0.05), neuronal damage was aggravated, the mitochondrial swelling and fracture of crista structure were accentuated in group LPS+ E; the preference index in novel object recognition, activities of mitochondrial respiratory chain complexes, MMP and ATP content were significantly increased ( P<0.05), neuronal damage was alleviated, and the mitochondrial swelling and fracture of crista structure were ameliorated in group LPS+ S. Conclusions:Activation of SIRT1 can improve mitochondrial dysfunction and alleviate LPS-induced brain injury in mice.

Effect of electroacupuncture on calcium homeostasis in hippocampal neurons of mice with sepsis-associated encephalopathy / 中华麻醉学杂志

Objective:To investigate the effect of electroacupuncture on calcium homeostasis in hippocampal neurons of mice with sepsis-associated encephalopathy (SAE).Methods:Twenty-four healthy male C57BL/6J mice, weighing 18-22 g, were divided into 4 groups ( n=6 each) using a random number table method: sham operation group (Sham group), SAE group, SAE plus electroacupuncture group (SAE+ EA group), and SAE plus sham electroacupuncture group (SAE+ SEA group). The virus carrying calcium ion (Ca 2+ ) fluorescent probes was injected and then an optical fiber was implanted into the hippocampal CA1 area to record the fluorescence signals of Ca 2+ . SAE was induced by cecal ligation and puncture in anesthetized mice at 3 weeks after administration. Starting from 3 days before surgery, Baihui and bilateral Quchi and bilateral Zusanli acupoints were stimulated for 30 min per day for 7 consecutive days in SAE+ EA group. In SAE+ SEA group, electroacupuncture was performed at the points 0.2 mm lateral to the corresponding acupoints without electrical stimulation. Open field tests were conducted at 5 days after surgery to record the number of rearing and changes in related Ca 2+ signals in hippocampal CA1 neurons. Novel object recognition tests were conducted at 6-7 days after surgery to record the recognition time and changes in related Ca 2+ signals in hippocampal CA1 neurons. Mice were sacrificed after the end of behavioral testing on 7 days after surgery, and brain tissues ipsilateral to the optical fiber implant were obtained and the fluorescence intensity of Ca 2+ in the hippocampal CA1 neurons was acquired using a fluorescent microscope. Results:Compared with Sham group, the number of rearing and amplitudes of related Ca 2+ signals in hippocampal CA1 neurons while rearing were significantly decreased in SAE group and SAE+ SEA group ( P<0.05), and no statistically significant changes were found in the parameters mentioned above in SAE+ EA group ( P>0.05), and the recognition index and amplitudes of related Ca 2+ signals while recognizing were significantly deceased, and the fluorescence intensity of Ca 2+ in hippocampal CA1 neurons was increased in SAE, SAE+ EA and SAE+ SEA groups ( P<0.05). Compared with SAE group and SAE+ SEA group, the number of rearing and amplitudes of related Ca 2+ signals in hippocampal CA1 neurons while rearing were significantly increased, the recognition index and amplitudes of related Ca 2+ signals in hippocampal CA1 neurons while recognizing were increased, and the fluorescence intensity of Ca 2+ in hippocampal CA1 neurons was decreased in SAE+ EA group ( P<0.05). There were no statistically significant differences in the parameters mentioned above between SAE group and SAE+ SEA group ( P>0.05). Conclusions:The mechanism by which electroacupuncture alleviates SAE may be related to regulation of Ca 2+ homeostasis in hippocampal neurons of mice.

Role of PIAS-regulated SUMOylation of PPARγ in endogenous protective mechanism against endotoxin-induced acute lung injury in mice / 中华麻醉学杂志

Objective:To evaluate the role of small ubiquitin-associated modifier (SUMO) E3 ligase (PIAS)-regulated SUMOylation of peroxisome proliferator-activated receptor γ (PPARγ) in the endogenous protective mechanism against endotoxin-induced acute lung injury (ALI) in mice.Methods:Experiment Ⅰ Twenty-four clean-grade wild type male C57BL/6 mice, aged 6-8 weeks, weighing 18-22 g, were divided into 4 groups ( n=6 each) using a random number table method: control group (C group), ALI group, ALI+ PPARγ inducer TZD group (ALI+ T group) and ALI+ TZD+ SUMOylation inhibitor anacardic acid group (ALI+ T+ A group). Lipopolysaccharide (LPS) 15 mg/kg was injected into the tail vein to develop the ALI model. In ALI+ T+ A group, anacardic acid 5 mg/kg was intraperitoneally injected at 1 h before LPS administration. In ALI+ T group and ALI+ T+ A group, TZD 50 mg/kg was intraperitoneally injected at 30 min before LPS administration. The mice were sacrificed at 12 h after LPS administration, and the lung tissues were obtained to examine the pathological changes which were scored and to determine the wet/dry (W/D) weight ratio, and expression of PIAS1, PIAS2, PIAS3 and PIASy protein and mRNA (by Western blot or polymerase chain reaction). Experiment Ⅱ Mouse alveolar macrophages (MH-S cells) were cultured in vitro and divided into 4 groups ( n=5 each) using a random number table method: control group (C group), LPS group, LPS+ PIAS2 siRNA group (L+ P group) and LPS+ Con siRNA group (L+ C group). Cells were routinely cultured in group C. Cells were stimulated with 10 μg/ml LPS to develop the model of endotoxin challenge. PIAS2 siRNA 50 nmol/L and Con siRNA 50 nmol/L were transfected at 48 h before LPS was added in L+ P group and L+ C group, respectively. The cells were collected at 24 h of incubation with LPS to determine the cell viability, levels of M1 and M2 alveolar macrophages (by flow cytometry), expression of PIAS2 and PPARγ (by Western blot), co-expression of PPARγ-SUMO1 (by immunoprecipitation) and expression of tumor necrosis factor-alpha (TNF-α) and interleukin-10 (IL-10) mRNA (by polymerase chain reaction). The ratio of M1/M2 was calculated. Results:Experiment Ⅰ Compared with C group, the lung injury scores and W/D ratio were significantly increased, and the expression of PIAS2 protein and mRNA was up-regulated in the other three groups ( P<0.05). Compared with ALI group, the lung injury scores and W/D ratio were significantly decreased, and the expression of PIAS2 protein and mRNA was up-regulated in ALI+ T group and ALI+ T+ A group ( P<0.05). Compared with ALI+ T group, the lung injury scores and W/D ratio were significantly increased, and the expression of PIAS2 protein and mRNA was down-regulated in ALI+ T+ A group ( P<0.05). There was no significant difference in the expression of PIAS1, PIAS3 and PIASy protein and mRNA in lung tissues among the four groups ( P>0.05). Experiment Ⅱ Compared with C group, the cell viability was significantly decreased, the expression of PPARγ and co-expression of PPARγ-SUMO1 was up-regulated, the levels of M1 and M2 macrophages and M1/M2 ratio were increased, the expression of TNF-α mRNA was up-regulated, and the expression of IL-10 mRNA was down-regulated in the other three groups, and PIAS2 expression was significantly up-regulated in L group and L+ C group ( P<0.05). Compared with L group, the cell viability was significantly decreased, the expression of PIAS2 and PPARγ and PPARγ-SUMO1 co-expression were down-regulated, the M1 macrophage level and M1/M2 ratio were increased, TNF-α mRNA expression was up-regulated, and the expression of IL-10 mRNA was down-regulated in L+ P group ( P<0.05), and no significant change was found in the parameters mentioned above in L+ C group ( P>0.05). Compared with L+ C group, the cell viability was significantly decreased, the expression of PIAS2 and PPARγ and co-expression of PPARγ-SUMO1 were down-regulated, the level of M1 alveolar macrophages and M1/M2 ratio were increased, the expression of TNF-α mRNA was down-regulated, and the expression of IL-10 mRNA was up-regulated in L+ P group ( P<0.05). Conclusions:PIAS2-regulated SUMOylation of PPARγ is the endogenous protective mechanism against endotoxin-induced ALI in mice, which may be related to inhibition of macrophage polarization into M1 type and alleviation of inflammatory responses.

Relationship between HO-1 and PPARγ during alveolar macrophage polarization in a mouse model of endotoxin-induced acute lung injury / 中华麻醉学杂志

Objective:To evaluate the relationship between heme oxygenase-1 (HO-1) and peroxisome proliferator-activated receptor γ (PPARγ) during alveolar macrophage polarization in a mouse model of endotoxin-induced acute lung injury (ALI).Methods:Thirty clean-grade male C57BL/6 mice (24 wide-type mice and 6 HO-1 knockout mice), aged 6-8 weeks, weighing 18-22 g, were studied.Wide-type mice were divided into 4 groups ( n=6 each) using a random number table method: control group (C group), ALI group, ALI+ HO-1 agonist hemin group (ALI+ H group), and ALI+ hemin+ PPARγ antagonist T0070907 group (ALI+ H+ T group).HO-1 knockout mice in which the ALI model was developed served as ALI+ HO-1 -/- group.ALI model was developed by injecting lipopolysaccharide (LPS) 15 mg/kg via the tail vein in anesthetized animals.T0070907 1.5 mg/kg was intraperitoneally injected at 1 h before LPS administration in ALI+ H+ T group, and hemin 50 mg/kg was intraperitoneally injected at 30 min before LPS administration in ALI+ H group and ALI+ H+ T group.Mice were sacrificed at 12 h after LPS administration, and lung tissues were obtained to measure the wet to dry weight ratio (W/D ratio), to observe pathological changes which were scored, and to determine the F4/80+ /CD86+ labeled M1 alveolar macrophages and the F4/80+ /CD206+ labeled M2 alveolar macrophages (by flow cytometry), contents of M1 macrophage-related genes inducible nitric oxide synthase (iNOS) and M2 macrophage-related genes Arginase-1 (Arg-1) (by enzyme-linked immunosorbent assay), and the expression of HO-1 and PPARγ (by Western blot). Results:Compared with C group, the lung injury score, W/D ratio, levels of CD86 and CD206, and contents of iNOS and Arg-1 were significantly increased, and PPARγ expression was up-regulated in the other four groups ( P<0.05), and HO-1 protein expression was up-regulated in ALI, ALI+ H and ALI+ H+ T groups ( P<0.05).Compared with ALI group, the lung injury score, W/D ratio, and levels of CD86 and iNOS were significantly increased, the levels of CD206 and Arg-1 were decreased, and the expression of HO-1 and PPARγ was down-regulated in ALI+ HO-1 -/- group, the lung injury score, W/D ratio and levels of CD86 and iNOS were significantly decreased, the levels of CD206 and Arg-1 were increased, and the expression of HO-1 and PPARγ was up-regulated in ALI+ H group ( P<0.05), and no significant change was found in the parameters mentioned above in ALI+ H+ T group ( P>0.05).Compared with ALI+ H group, the lung injury score, W/D ratio and levels of CD86 and iNOS were significantly increased, the levels of CD206 and Arg-1 were decreased, the expression of PPARγ was down-regulated ( P<0.05), and no significant change was found in the expression of HO-1 in ALI+ H+ T group ( P>0.05). Conclusions:HO-1 can up-regulate the expression of PPARγ, inhibit the polarization of alveolar macrophages toward M1 phenotype and promote the polarization toward M2 phenotype, thus playing an endogenous protective role in endotoxin-induced ALI in mice.

Effect of electroacupuncture on synaptic damage to hippocampal neurons in rats with sepsis-associated encephalopathy / 中华麻醉学杂志

Objective:To investigate the effect of electroacupuncture (EA) on synaptic damage to hippocampal neurons in rats with sepsis-associated encephalopathy (SAE).Methods:A total of 48 healthy adult male Sprague-Dawley rats, weighing 250-300 g, were divided into 4 groups ( n=12 each) using a random number table method: sham operation group (Sham group), SAE group, SAE+ EA group and SAE+ sham EA group (SAE+ SEA group). SAE was induced by cecal ligation and puncture in anesthetized rats.Baihui, Quchi and Zusanli acupoints were stimulated with constant voltage (2/15 Hz) and disperse-dense waves for 30 min once a day for 10 consecutive days, and the stimulation intensity was defined as less than 1.5 mA causing slight muscle contraction at 2 days before operation in group SAE+ EA.In group SAE+ SEA, stimulating electrodes were placed at the points 5 mm lateral to the corresponding acupoints, but no electrical stimulation was applied.On day 14 after operation, the rats were sacrificed, and hippocampal tissues were obtained and stained with haematoxylin and eosin for examination of the pathological changes in the hippocampal CA1 region, for determination of the expression of synaptophysin (SYN) and postsynaptic density protein 95 (PSD-95) (by Western blot), and for calculation of dendritic spine density of neurons in the hippocampal CA1 area (using Golgi staining) and pyramidal neurons counts. Results:Compared with Sham group, the expression of SYN and PSD-95 in hippocampus was significantly decreased, and the basal and apical dendrite spine density of neurons in hippocampal CA1 area was decreased in SAE group, the expression of PSD-95 was decreased, and the apical dendrite spine density of neurons in the hippocampal CA1 area was increased in SAE+ EA group, and the pyramidal neuron counts in the hippocampal CA1 area were reduced in SAE, SAE+ EA and SAE+ SEA groups ( P<0.05). Compared with group SAE, the expression of SYN and PSD-95 was significantly up-regulated, the basal and apical dendrite spine density of neurons in the hippocampal CA1 area was increased and the pyramidal neuron counts were increased in group SAE+ EA ( P<0.05), the pathological damage of hippocampal CA1 area was alleviated and no significant change was found in the parameters mentioned above in group SAE+ SEA ( P>0.05). Compared with group SAE+ EA, the expression of SYN and PSD-95 was down-regulated, the basal and apical dendrite spine density of neurons in the hippocampal CA1 area was decreased, and the pyramidal neuron counts were reduced in SAE+ SEA group ( P<0.05). Conclusion:The mechanism by which EA alleviates SAE may be related to reducing synaptic damage to hippocampal neurons in rats.

Effect of electroacupuncture pretreatment on oxidative stress response of hippocampus in rats with sepsis-associated encephalopathy and relationship with Nrf2/HO-1 signaling pathway / 中华麻醉学杂志

Objective:To evaluate the effect of electroacupuncture (EA) pretreatment on oxidative stress response of hippocampus in rats with sepsis-associated encephalopathy (SAE) and the relationship with nuclear factor E2-related factor 2 (Nrf2)/heme oxygenase-1 (Nrf2/HO-1) signaling pathway.Methods:A total of 64 healthy adult male Sprague-Dawley rats, weighing 250-300 g, were divided into 4 groups ( n=16 each) using a random number table method: sham operation group (Sham group), SAE group, SAE+ EA group and SAE plus sham EA group (SAE+ SEA group). In SAE+ EA group, Baihui, Quchi and Zusanli acupoints were stimulated for 30 min once a day for 5 consecutive days.Sepsis was induced by cecal ligation and puncture immediately after the end of the last EA.At 1 and 7 days after establishment of the model, the hippocampal malondialdehyde (MDA) and superoxide dismutase (SOD) levels were detected by enzyme-linked immunosorbent assay, the expression of hippocampal Nrf2 mRNA was detected using real-time reverse transcription polymerase chain reaction, and the expression of Nrf2 and HO-1 was determined by Western blot.At 3-7 days after establishment of the model, cognitive function was assessed using the Morris water maze test, and the escape latency and the target quadrant exploration time were recorded. Results:Compared with Sham group, the content of MDA was significantly increased and the activity of SOD was decreased at 1 and 7 days after establishment of the model, the expression of Nrf2 protein and mRNA and HO-1 was down-regulated at day 7 after establishment of the model, the escape latency was prolonged, and the target quadrant exploration time was shortened in SAE group ( P<0.05). Compared with SAE group, the content of MDA was significantly decreased and the activity of SOD was increased at 1 and 7 days after establishment of the model, the expression of Nrf2 protein and mRNA and HO-1 was up-regulated at day 7 after establishment of the model, the escape latency was shortened, and the target quadrant exploration time was prolonged in group SAE+ EA ( P<0.05), and no significant change was found in the parameters mentioned above in group SAE+ SEA ( P>0.05). Conclusion:EA pretreatment can reduce oxidative stress response of hippocampus in rats with SAE, and the mechanism may be related to activating Nrf2/HO-1 signaling pathway.

Role of HO-1 in electroacupuncture-induced alleviation of cognitive dysfunction in mice with sepsis-associated encephalopathy: relationship with mitochondrial fusion-division balance / 中华麻醉学杂志

Objective:To evaluate the role of heme oxygenase-1 (HO-1) in electroacupuncture (EA)-induced alleviation of cognitive dysfunction in mice with sepsis-associated encephalopathy (SAE) and the relationship with mitochondrial fusion-division balance.Methods:Thirty clean-grade male C57BL/6 mice (24 wide-type mice and 6 HO-1 knockout mice), aged 6-8 weeks, weighing 18-22 g, were studied.Twenty-four wide-type mice were divided into 4 groups ( n=6 each) using a random number table method: control group (group C), SAE group, SAE plus EA group (group SAE+ EA), and SAE plus sham EA group (group SAE+ SEA). HO-1 knockout mice in which EA intervention was performed after establishing SAE model served as SAE plus EA plus HO-1 knockout group (group SAE + EA+ H). Sepsis was induced by intraperitoneally injecting lipopolysaccharide 15 mg/kg.EA of Zusanli and Baihui acupoints lasting 30 min was performed after intraperitoneal injection of lipopolysaccharide once a day for 5 consecutive days in SAE+ EA and SAE+ EA+ H groups.Cognitive function was assessed using Morris water maze test before stimulation every day.The mice were sacrificed, and hippocampal tissues were removed for detection of the expression of mitofusin 2 (Mfn2), optic atrophy 1 (OPA1) and mitochondrial dynamin-related protein 1 (Drp1) by Western blot. Results:Compared with group C, the expression of Mfn2 and OPA1 was significantly down-regulated, the escape latency was prolonged, and the time spent in the target quadrant was shorted in SAE, SAE+ SEA and SAE+ EA+ H groups, and the expression of Drp1 was significantly up-regulated in SAE, SAE+ EA, SAE+ SEA and SAE+ EA+ H groups ( P<0.05). Compared with group SAE, the expression of Mfn2 and OPA1 was significantly up-regulated, the expression of Drp1 was down-regulated, the escape latency was shortened, and the time spent in the target quadrant was prolonged in group SAE+ EA ( P<0.05), and no significant change was found in the parameters mentioned above in group SAE+ SEA ( P>0.05). Compared with group SAE+ EA, the expression of Mfn2 and OPA1 was significantly down-regulated, the expression of Drp1 was up-regulated, the escape latency was prolonged, and the time spent in the target quadrant was shortened in SAE+ SEA and SAE+ EA+ H groups ( P<0.05). Conclusion:HO-1 is involved in EA-induced alleviation of cognitive dysfunction in mice with SAE, and the mechanism may be related to the regulation of mitochondrial mitochondrial fusion-division balance.

Effect of electroacupuncture on lung injury caused by extremity ischemia-reperfusion / 中华麻醉学杂志

Objective:To evaluate the effect of electroacupuncture (EA) on lung injury caused by extremity ischemia-reperfusion.Methods:Forty-five American Society of Anesthesilogists physical status ⅠorⅡpatients, aged 20-60 yr, with body mass index of 18-28 kg/m 2, undergoing unilateral lower extremity operation requiring tourniquet with neuraxial anesthesia were divided into 3 groups ( n=15 each) using a random number table method: control group (C group), EA group and EA at non-acupoint group (group N). Bilateral acupoints Feshu and Zusanli were stimulated with disperse-dense waves, frequency 2/15 Hz, the current intensity the maximum current that patients could tolerant until the end of surgery in group EA.EA was performed at the points 1 cm lateral to the acupoints of Feshu and Zusanli in group N. Before anesthesia (T 1) and at 10, 30 and 60 min after tourniquet loosening (T 2-4), blood samples were collected from the radial artery for blood gas analysis, the partial pressure of arterial oxygen(PaO 2) and arterial carbon dioxide partial pressure (PaCO 2) were recorded, alveolar-arterial oxygen partial pressure difference (P A-aDO 2), oxygenation index (OI) and respiratory index (RI) were calculated, the malondialdehyde (MDA) content was measured by thiobarbituric acid method, the concentration of serum nitric oxide (NO) was determined by nitrate reductase method, and the concentrations of serum endothelin-1 (ET-1) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay. Results:Compared with the baseline at T 1, OI and RI were significantly decreased, P A-aO 2 was increased, and serum MDA, IL-6, ET-1 and NO levels were increased at T 2-4 in three groups ( P<0.05). Compared with group C, OI was significantly increased, P A-aO 2 and RI were decreased, serum MDA, IL-6, ET-1 and NO levels were decreased at T 2-4 in group EA ( P<0.05). Conclusion:EA can reduce lung injury caused by extremity ischemia-reperfusion, and the mechanism may be related to maintaining NO/ET-1 balance.

Role of hippocampal HO-1 in electroacupuncture-induced reduction of lipopolysaccharide-induced brain injury in mice / 中华麻醉学杂志

Objective:To evaluate the role of hippocampal hemeoxygenase-1 (HO-1) in electroacupuncture (EA)-induced reduction of lipopolysaccharide (LPS)-induced brain injury in mice.Methods:Twenty-four healthy adult C57BL/6J mice of both sexes, weighing 18-22 g, were divided into 4 groups ( n=6 each) using a random number table method: control group (group C), LPS-induced brain injury group (LPS group), LPS plus EA group, and LPS plus EA plus HO-1 inhibitor zinc protoporphyria (ZnPP) group (LPS+ EA+ ZnPP group). A virus carrying calcium ion fluorescent probes was injected into and an optical fiber was implanted into the hippocampal CA1 region to record changes in the calcium fluorescence signals.Three weeks later, Baihui, Quchi and Zusanli acupoints were stimulated with constant voltage (2/15 Hz) and disperse-dense waves for 30 min once a day for 5 consecutive days, and the stimulation intensity was defined as less than 1 mA causing slight muscle contraction.ZnPP 50 μmol/kg was intraperitoneally injected at 12 h before each stimulation in LPS+ EA+ ZnPP group, and the equal volume of normal saline was given instead in the other groups.After the end of EA stimulation on the last day, LPS 5 mg/kg was intraperitoneally injected to induce brain injury.Open field tests were performed at 1 day after LPS injection to record the number of rearing and amplitude of neuronal calcium signals during rearing.Novel object recognition tests were conducted at 3 days after LPS injection, and the exploration index and amplitude of neuronal calcium signals while exploring novel objects were recorded.The mice were sacrificed after the end of behavioral testing, and the brain tissues were obtained and stained by Nissl, and the neurons in the hippocampal CA1 region were counted. Results:Compared with group C, the number of rearing and amplitude of calcium signals in neurons in the hippocampal CA1 region during rearing were significantly decreased, the exploration index and amplitude of calcium signals in neurons in the hippocampal CA1 region while exploring novel objects were decreased, and the neuron counts were reduced in LPS, LPS+ EA and LPS+ EA+ ZnPP groups ( P<0.05 or 0.01). Compared with group LPS, the number of rearing and amplitude of calcium signals in neurons in the hippocampal CA1 region during rearing were significantly increased, and the exploration index and amplitude of calcium signals in neurons in the hippocampal CA1 region while exploring novel objects were increased in group LPS+ EA ( P<0.05), and no significant change was found in the parameters mentioned above in group LPS+ EA+ ZnPP ( P>0.05). Compared with group LPS+ EA, the number of rearing and amplitude of calcium signals in neurons in the hippocampal CA1 region during rearing were significantly decreased, and the exploration index and amplitude of calcium signals in neurons in the hippocampal CA1 region while exploring novel objects were decreased in group LPS+ EA+ ZnPP ( P<0.05). Conclusion:The mechanism by which EA reduces LPS-induced brain injury is related to the activation of the endogenous protective mechanism HO-1 in mice.

Mechanism of melatonin alleviating lipopolysaccharide-induced damage to type Ⅱ alveolar epithelial cells of rats: relationship between melatonin receptors and mitochondrial fission proteins / 中华麻醉学杂志

Objective:To evaluate the relationship between melatonin receptors and mitochondrial fission proteins and to clarify the mechanism of melatonin alleviating lipopolysaccharide(LPS)-induced damage to type Ⅱ alveolar epithelial cells of rats.Methods:The rat type Ⅱalveolar epithelial cells were seeded in 6-well plates at a density of 2×10 5 cells/ml and divided into 5 groups ( n=10 each) using a random number table method: control group (C group), LPS group (L group), LPS plus melatonin group (LM group), LPS plus melatonin receptor blocking group (LL group), and LPS plus melatonin plus melatonin receptor blocker group (LML group). The model of LPS-induced damage to cells was established by incubating with LPS 10 μg/ml for 24 h. Melatonin 0.1 mmol/L and/or melatonin receptor blocker luzindole 0.2 μmol/L was added in LM group, LL group and LML group.The concentrations of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay after the end of incubation.The mitochondrial respiratory control rate (RCR) was measured by GENMED purified mitochondrial RCR quantitative detection kit in each group.Western blot was used to detect the expression of dynamin-related protein 1 (Drp1) and mitochondrial adaptor fission 1 (Fis1). Results:Compared with C group, the concentrations of TNF-α and IL-6 in culture medium were significantly increased, RCR was decreased, and the expression of Drp1 and Fis1 was up-regulated in L, LM, LL and LML groups ( P<0.05). Compared with L group, the concentrations of TNF-α and IL-6 in culture medium were significantly decreased, RCR was increased, and the expression of Drp1 and Fis1 was down-regulated in LM group ( P<0.05), and no significant change was found in parameters mentioned above in LL group ( P>0.05). Compared with LM group, the concentrations of TNF-α and IL-6 in culture medium were significantly increased, RCR was decreased, and the expression of Drp1 and Fis1 was up-regulated in LML group ( P<0.05). Conclusion:The mechanism by which melatonin attenuates LPS-induced damage to type Ⅱ alveolar epithelial cells is related to activating melatonin receptors and inhibiting the expression of mitochondrial fission proteins in rats.

Role of HO-1-induced endogenous protection in LPS-caused apoptosis in rat alveolar macrophages: relationship with endoplasmic reticulum stress / 中华麻醉学杂志

Objective:To evaluate the role of heme oxygenase-1 (HO-1)-induced endogenous protection in lipopolysaccharide (LPS)-caused apoptosis in rat alveolar macrophages and the relationship with endoplasmic reticulum stress.Methods:Alveolar macrophages of rats were randomized into 4 groups ( n=32 each) using a random number table method: control group (group C), LPS group (group L), Con siRNA group and HO-1 siRNA group. Cells were cultured normally in group C, and 10 μg/ml LPS was added to the culture medium in the other three groups. Con siRNA and HO-1 siRNA transfection was performed at 48 h before adding LPS in Con siRNA and HO-1 siRNA groups. At 24 h of treatment with LPS, MTT method was used to measure the cell viability, flow cytometry was used to determine the cell apoptosis rate, and Western blot was used to detect the expression of glucose regulatory protein 78 (GRP78), phosphorylated kinase receptor-like endoplasmic reticulum kinase (p-PERK), CCAAT/enhancer-binding protein homologous protein (CHOP), phosphorylated type I endoplasmic reticulum transmembrane protein kinase (p-IRE-1), phosphorylated stress-activated protein kinase (p-JNK) and caspase-12. Results:Compared with group C, the cell viability was significantly decreased, cell apoptosis rate was increased, and the expression of HO-1, GRP78, CHOP, p-PERK, p-IRE-1, p-JNK and caspase-12 was up-regulated in the other three groups ( P<0.05). Compared with group L, the cell viability was significantly decreased, cell apoptosis rate was increased, and the expression of HO-1 was down-regulated, and the expression of GRP78, CHOP, p-PERK, p-IRE-1, p-JNK and caspase-12 was up-regulated in group HO-1 siRNA ( P<0.05), and no significant change was found in each parameter in group Con siRNA ( P>0.05). Compared with group Con siRNA, the cell viability was significantly decreased, cell apoptosis rate was increased, and the expression of HO-1 was down-regulated, and the expression of GRP78, CHOP, p-PERK, p-IRE-1, p-JNK and caspase-12 was up-regulated in group HO-1 siRNA ( P<0.05). Conclusion:The mechanism of HO-1-induced endogenous protection is related to inhibiting endoplasmic reticulum stress and then reducing LPS-induced apoptosis in alveolar macrophages of rats.

Role of melatonin in electroacupuncture-induced reduction of lung injury induced by limb ischemia-reperfusion in rabbits / 中华麻醉学杂志

Objective:To evaluate the role of melatonin in electroacupuncture (EA)-induced reduction of lung injury induced by limb ischemia-reperfusion (I/R) in rabbits.Methods:Fifty clean-grade healthy male New Zealand white rabbits, weighing 2.0-2.5 kg, aged 3 months, were divided into 5 groups ( n=10 each) using a random number table method: sham operation group (group Sham), limb I/R group (group IR), EA group, sham EA group (group SEA) and EA plus melatonin receptor antagonist luzindele group (group EA+ L). The model of limb I/R injury was established by clamping the femoral artery for 3 h followed by 4-h reperfusion in anesthetized animals.In group EA and group EA + L, bilateral Zusanli and Feishu acupoints (4-6 mm depth) were stimulated with constant voltage (2/15 Hz, l-2 mA, disperse-dense waves) for 30 min once a day during 1-7 days before establishing the model and during establishment of the model.EA was performed at the points (3 mm depth) 0.5 cm lateral to the acupoints of Zusanli and Feishu instead in group SEA.Luzinole 30 mg/kg was intraperitoneally injected at 30 min before establishing the model in group EA+ L.Blood samples from the right internal jugular vein were collected before ischemia (T 0), at 3 h of ischemia (T 1) and 4 h of reperfusion (T 2) for determination of the serum melatonin concentrations by enzyme-linked immunosorbent assay.Bronchoalveolar lavage fluid (BALF) was collected at 4 h of reperfusion for measurement of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and IL-6 concentrations (by enzyme-linked immunosorbent assay), superoxide dismutase (SOD) activity (by xanthine oxidase method), and malondialdehyde (MDA) concentration (by thiobarbituric acid method). Then the rabbits were sacrificed, and the lung tissues were taken for determination of wet to dry weight ratio (W/D ratio) and for microscopic examination of the pathological changes (with a light microscope) which were scored and ultrastructure (with a transmission electron microscope). The number of mitochondria and relative cross-sectional area of mitochondria were calculated. Results:Compared with group Sham, lung injury scores and W/D ratio were significantly increased, the number of mitochondria was decreased, the relative cross-sectional area of mitochondria was increased, levels of TNF-α, IL-1β, IL-6 and MDA in BALF were increased, and activities of SOD in BALF were decreased in the other four groups, and the serum melatonin concentration was decreased at T 1 and T 2 in group I/R and increased at T 0 in EA and EA+ L groups ( P<0.05). Compared with group IR, the lung injury score and W/D ratio were significantly decreased, the number of mitochondria was increased, the relative cross-sectional area of mitochondria was decreased, levels of TNF-α, IL-1β, IL-6 and MDA in BALF were decreased, and activities of SOD in BALF were increased in group EA, the serum melatonin concentration was increased at each time point in EA and EA+ L groups ( P<0.05), and no significant change was found in the parameters mentioned above in group SEA ( P>0.05). Compared with group EA, lung injury scores and W/D ratio were significantly increased, the number of mitochondria was decreased, the relative cross-sectional area of mitochondria was increased, levels of TNF-α, IL-1β, IL-6 and MDA in BALF were increased, and activities of SOD in BALF were decreased in SEA and EA+ L groups, and the serum melatonin concentration was decreased at each time point in group SEA ( P<0.05). Conclusion:EA can reduce lung injury induced by limb I/R by increasing serum melatonin level in rabbits.

Best time for detecting experiment of fractional exhaled nitric oxide in young wheezing children / 中华实用儿科临床杂志

Objective@#To study the correlation between fractional exhaled nitric oxide (FeNO) and lung function in young children for acute attack of wheezing, and to compare the FeNO in different stages in order to explore the best suitable time for the experiment of FeNO in young children by the method of on-line tidal breathing.@*Methods@#Recurrent wheezing children aged 1-5 year old were selected who were underwent the test at lung function laboratory from January 2016 to March 2018, at Guangzhou Women and Children′s Medical Center.The children aged less than 5 years old were detected for FeNO in both stages of acute exacerbation and 2 weeks after treatment, and the children aged less than 3 years were also detected for the tidal lung function in the acute exacerbation stage.According to time ratio of reaching tidal peak flow to total expiratory time(TPTEF/TE )and ratio of volume at tidal peak flow to total tidal volume (VPEF/VE), the children aged less than 3 years were divided into 4 groups (normal group, mild group, moderate group and severe group).@*Results@#The FeNO of the normal group[9.85(5.17, 19.62) ppb] and mild group[13.00(7.00, 23.30) ppb] were significantly higher than that of the severe group [3.10(2.20, 5.25) ppb], and the differences were statistically significant(all P<0.05). And there was a positive correlation between TPTEF/TE and FeNO(r=0.304, P<0.05), VPEF/VE and FeNO(r=0.320, P<0.05), tidal volume per kilogram(VT/kG)and FeNO(r=0.293, P<0.05)and a negative correlation between respiration rate(RR)and FeNO(r=-0.449, P<0.05). The FeNO in the stage of acute exacerbation was significantly lower than that in the stage of 2 weeks after treatment[(10.49±8.49) ppb vs.(20.41±9.13) ppb], and there was a significant difference among them(t=-5.79, P<0.01).@*Conclusions@#If researchers want to use the method of on-line breathing to test FeNO in young children with wheezing, they should choose the time of 2 weeks after treatment, and analyze the results combined with the lung function.

Effect of dexmedetomidine on mitochondrial dynamics in mice with endotoxin-induced acute lung injury / 中华麻醉学杂志

Objective@#To evaluate the effect of dexmedetomidine on mitochondrial dynamics in mice with endotoxin-induced acute lung injury (ALI).@*Methods@#Thirty clean-grade healthy adult male C57BL/6 mice, weighing 20-25 g, aged 2 months, were divided into 3 groups (n=10 each) using a random number table method: control group (group C), endotoxin-induced ALI group (group LPS) and endotoxin-induced ALI plus dexmedetomidine group (group LPS+ DEX). In LPS and LPS+ DEX groups, lipopolysaccharide (LPS) 10 mg/kg was injected via the caudal vein to establish the model of endotoxin-induced ALI.In group LPS+ DEX, dexmedetomidine 50 μg/kg was intraperitoneally injected at 30 min before injection of LPS, while the equal volume of normal saline was given instead in C and LPS groups.The mice were sacrificed at 6 h after LPS administration, and lung tissues were obtained for examination of the pathological changes (with a light microscope) which were scored and for determination of the level of reactive oxygen species (ROS) and expression of mitochondrial fusion proteins mitofusin 1 (Mfn1), Mfn2, optic atrophy 1 (OPA1), dynamin-related protein 1 (Drp1) and fission protein 1 (Fis1)(using Western blot).@*Results@#Compared with group C, the lung injury scores and ROS level in lung tissues were significantly increased, the expression of Mfn1, Mfn2 and OPA1 was down-regulated, and the expression of Drp1 and Fis1 was up-regulated in LPS and LPS+ DEX groups (P<0.05). Compared with group LPS, the lung injury scores and ROS level in lung tissues were significantly decreased, the expression of Mfn1, Mfn2 and OPA1 was up-regulated, and the expression of Drp1 and Fis1 was down-regulated in group LPS+ DEX (P<0.05).@*Conclusion@#Dexmedetomidine can reduce endotoxin-induced ALI through maintaining the mitochondrial fusion-fission balance in mice.

Role of heme oxygenase-1 on lipopolysaccharide-induced activation of NLRP3 inflammasomes in alveolar macrophages of rats / 中华麻醉学杂志

Objective To evaluate the role of heme oxygenase-1 (HO-1) on lipopolysaccharide (LPS)-induced activation of NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasomes in alveolar macrophages of rats.Methods NR8383 cells of rat alveolar macrophages cultured in vitro were seeded in 96-well plates at a density of 4× 104 cells/ml and divided into 4 groups (n =48 each) using a random number table method:control group (group C),group LPS (group L),LPS+HO-1 siRNA group (group L+HO-1 siRNA),and LPS+Con siRNA group (group L+Con siRNA).The cells were cultured in normal culture atmosphere in group C.NR8383 cells were stimulated with 10 μg/ml LPS in L,L+HO-1 siRNA and L+Con siRNA groups.Cells were transfected with HO-1 siRNA at 48 h before stimulation with LPS in group L+HO-1 siRNA and with Con siRNA at 48 h before stimulation with LPS in group L+Con siRNA.The ceils were collected and incubated for 24 h after stimulation with LPS for measurement of the cell viability,expression of HO-1 and NLRP3 mRNA (by real-time polymerase chain reaction),expression of HO-1,NLRP3,apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC)and caspase-1 (by Western blot),and concentrations of interleukin-1beta (IL-1β) and interleukin-18 (IL-18) in the supernatant (by enzyme-linked immunosorbent assay).Results Compared with group C,the cell viability was significantly decreased,the expression of HO-1 and NLRP3 protein and mRNA,ASC and caspase-1 was up-regulated,and the IL-1β and IL-18 concentrations were increased in L,L+HO-1 siRNA and L+Con siRNA groups (P＜0.05).Compared with group L,the cell viability was significantly decreased,the expression of HO-1 protein and mRNA was down-regulated,and the expression of NLRP3 protein and mRNA,ASC and caspase-1 was up-regulated,and the IL-1β and IL-18 concentrations were increased in group L+HO-1 siRNA (P＜0.05),and no significant change was found in the parameters mentioned above in group L+Con siRNA (P＞0.05).Conclusion HO-1 is involved in LPS-induced activation of NLRP3 inflammasomes in alveolar macrophages of rats.

Effect of dexmedetomidine on mitochondrial dynamics in mice with endotoxin-induced acute lung injury / 中华麻醉学杂志

Objective To evaluate the effect of dexmedetomidine on mitochondrial dynamics in mice with endotoxin-induced acute lung injury (ALI).Methods Thirty clean-grade healthy adult male C57BL/6 mice,weighing 20-25 g,aged 2 months,were divided into 3 groups (n=10 each) using a random number table method:control group (group C),endotoxin-induced ALI group (group LPS) and endotoxin-induced ALI plus dexmedetomidine group (group LPS+DEX).In LPS and LPS+DEX groups,lipopolysaccharide (LPS) 10 mg/kg was injected via the caudal vein to establish the model of endotoxin-induced ALI.In group LPS+DEX,dexmedetomidine 50 μg/kg was intraperitoneally injected at 30 min before injection of LPS,while the equal volume of normal saline was given instead in C and LPS groups.The mice were sacrificed at 6 h after LPS administration,and lung tissues were obtained for examination of the pathological changes (with a light microscope) which were scored and for determination of the level of reactive oxygen species (ROS) and expression of mitochondrial fusion proteins mitofusin 1 (Mfn1),Mfn2,optic atrophy 1 (OPA1),dynamin-related protein 1 (Drp1) and fission protein 1 (Fis1) (using Western blot).Results Compared with group C,the lung injury scores and ROS level in lung tissues were significantly increased,the expression of Mfn1,Mfn2 and OPA1 was down-regulated,and the expression of Drp1 and Fis1 was up-regulated in LPS and LPS+DEX groups (P＜0.05).Compared with group LPS,the lung injury scores and ROS level in lung tissues were significantly decreased,the expression of Mfn1,Mfn2 and OPA1 was up-regulated,and the expression of Drp1 and Fis1 was down-regulated in group LPS+DEX (P＜ 0.05).Conclusion Dexmedetomidine can reduce endotoxin-induced ALI through maintaining the mitochondrial fusion-fission balance in mice.

Best time for detecting experiment of fractional exhaled nitric oxide in young wheezing children / 中华实用儿科临床杂志

Objective To study the correlation between fractional exhaled nitric oxide (FeNO) and lung function in young children for acute attack of wheezing,and to compare the FeNO in different stages in order to explore the best suitable time for the experiment of FeNO in young children by the method of on-line tidal breathing.Methods Recurrent wheezing children aged 1-5 year old were selected who were underwent the test at lung function laboratory from January 2016 to March 2018,at Guangzhou Women and Children's Medical Center.The children aged less than 5 years old were detected for FeNO in both stages of acute exacerbation and 2 weeks after treatment,and the children aged less than 3 years were also detected for the tidal lung function in the acute exacerbation stage.According to time ratio of reaching tidal peak flow to total expiratory time(TPTEF/TE) and ratio of volume at tidal peak flow to total tidal volume (VPEF/VE),the children aged less than 3 years were divided into 4 groups (normal group,mild group,moderate group and severe group).Results The FeNO of the normal group [9.85 (5.17,19.62) ppb] and mild group[13.00 (7.00,23.30) ppb] were significantly higher than that of the severe group [3.10 (2.20,5.25)ppb],and the differences were statistically significant (all P ＜ 0.05).And there was a positive correlation between TPTEF/TE and FeNO(r =0.304,P ＜ 0.05),VPEF/VE and FeNO(r =0.320,P ＜ 0.05),tidal volume per kilogram (VT/kG) and FeNO(r =0.293,P ＜ 0.05)and a negative correlation between respiration rate(RR) and FeNO (r =-0.449,P ＜ 0.05).The FeNO in the stage of acute exacerbation was significantly lower than that in the stage of 2 weeks after treatment[(10.49± 8.49) ppb vs.(20.41 ± 9.13) ppb],and there was a significant difference among them(t =-5.79,P ＜ 0.01).Conclusions If researchers want to use the method of on-line breathing to test FeNO in young children with wheezing,they should choose the time of 2 weeks after treatment,and analyze the results combined with the lung function.

Role of heme oxygenase-1 on lipopolysaccharide-induced activation of NLRP3 inflammasomes in alveolar macrophages of rats / 中华麻醉学杂志

Objective@#To evaluate the role of heme oxygenase-1 (HO-1) on lipopolysaccharide (LPS)-induced activation of NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasomes in alveolar macrophages of rats.@*Methods@#NR8383 cells of rat alveolar macrophages cultured in vitro were seeded in 96-well plates at a density of 4×104 cells/ml and divided into 4 groups (n=48 each) using a random number table method: control group (group C), group LPS (group L), LPS+ HO-1 siRNA group (group L+ HO-1 siRNA), and LPS+ Con siRNA group (group L+ Con siRNA). The cells were cultured in normal culture atmosphere in group C. NR8383 cells were stimulated with 10 μg/ml LPS in L, L+ HO-1 siRNA and L+ Con siRNA groups.Cells were transfected with HO-1 siRNA at 48 h before stimulation with LPS in group L+ HO-1 siRNA and with Con siRNA at 48 h before stimulation with LPS in group L+ Con siRNA.The cells were collected and incubated for 24 h after stimulation with LPS for measurement of the cell viability, expression of HO-1 and NLRP3 mRNA (by real-time polymerase chain reaction), expression of HO-1, NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and caspase-1 (by Western blot), and concentrations of interleukin-1beta (IL-1β) and interleukin-18 (IL-18) in the supernatant (by enzyme-linked immunosorbent assay).@*Results@#Compared with group C, the cell viability was significantly decreased, the expression of HO-1 and NLRP3 protein and mRNA, ASC and caspase-1 was up-regulated, and the IL-1β and IL-18 concentrations were increased in L, L+ HO-1 siRNA and L+ Con siRNA groups (P<0.05). Compared with group L, the cell viability was significantly decreased, the expression of HO-1 protein and mRNA was down-regulated, and the expression of NLRP3 protein and mRNA, ASC and caspase-1 was up-regulated, and the IL-1β and IL-18 concentrations were increased in group L+ HO-1 siRNA (P<0.05), and no significant change was found in the parameters mentioned above in group L+ Con siRNA (P>0.05).@*Conclusion@#HO-1 is involved in LPS-induced activation of NLRP3 inflammasomes in alveolar macrophages of rats.

Endotoxin-induced endogenous protective mechanism of alveolar type Ⅱ epithelial cells of rats: the relationship with p38MAPK-HO-1-mitochondrial fusion signaling pathway / 中华麻醉学杂志

Objective To evaluate the endotoxin-induced endogenous protective mechanism of alveolar type Ⅱ epithelial cells of rats and the relationship with p38 mitogen-activated protein kinase (p38MAPK)-HO-1-mitochondrial fusion signaling pathway.Methods Rat alveolar type Ⅱ epithelial cells were seeded in 6-well plates at a density of 2× 105 cells/ml and divided into 5 groups (n =15 each) using a random number table method:control group (group C),lipopolysaccharide (LPS) group (group L),LPS plus p38MAPK inhibitor SB203580 group (group LS),LPS plus dimethyl sulfoxide group (group LD),and SB203580 group (group S).Cells were conventionally cultured in group C.The model of endotoxin-challenged alveolar type Ⅱ epithelial cells was established by giving LPS 10 μg/ml in L,LS and LD groups.SB203580 10 μmol and 0.1％ dimethyl sulfoxide 100 μμmol were added at 1 h before giving LPS in group LS and group LD,respectively.SB203580 10 μ mol was added to the culture medium in group S.All the cells were incubated for 24 h.The malonaldehyde (MDA) content and superoxide dismutase (SOD) activity in the culture medium were determined by thiobarbituric acid assay and xanthine oxidase method,respectively.The expression of p38MAPK,phosphorylated p38MAPK (p-p38MAPK),hemeoxygenase-1 (HO-1),mitofusin 1 (Mfn1),Mfn2,and optical atrophy-1 (OPA1) was measured by Western blot.Results Compared with group C,the MDA content was significantly increased,the SOD activity was decreased,and the expression of p-p38MAPK and HO-1 was up-regulated,and the expression of Mfn1,Mfn2 and OPA1 was down-regulated in L,LS and LD groups (P＜0.05).Compared with group L,the MDA content was significantly increased,the SOD activity was decreased,and the expression of pp38MAPK,HO-1,Mfn1,Mfn2 and OPA1 was down-regulated in group LS (P＜0.05),and no significant change was found in the indices mentioned above in group LD (P＞0.05).Conclusion The endotoxin-induced endogenous protective mechanism of alveolar type Ⅱ epithelial cells is related to p38MAPK-HO-1-mitochondrial fusion signaling pathway in rats.

Role of endogenous heme oxygenase-1/carbon monoxide signaling pathway in endoplasmic reticulum stress during endotoxin-induced acute lung injury in rats / 中华麻醉学杂志

Objective To evaluate the role of endogenous heme oxygenase-1/carbon monoxide ( HO-1/CO) signaling pathway in endoplasmic reticulum stress during endotoxin-induced acute lung injury ( ALI) in rats. Methods Forty healthy clean-grade male Sprague-Dawley rats, aged 8 weeks, weighing 190-210 g, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), ALI group, ALI plus ZnPP-IX group (group AZ), and ALI plus vehicle sodium bicarbonate group ( group AV) . ALI was induced by intravenously injecting lipopolysaccharide 5 mg/kg in anesthetized rats. At 30 min before establishing the model, ZnPP-IX 10μmol/kg (diluted to 1 ml in 50 mmol/L sodium bicarbonate) was intraperitoneally injected in group AZ, and 50 mmol/L sodium bicarbonate 1 ml was intra-peritoneally injected in group AV. After injecting lipopolysaccharide for 6 h, blood samples were collected from the common carotid artery for determination of plasma CO concentration, the rats were then sacrificed, and lungs were removed for microscopic examination of the pathological changes which were scored and for determination of CO level, wet to dry weight ratio ( W/D ratio) , cell apoptosis ( by TUNEL) , and expres-sion of heme oxygenase-1 ( HO-1) , glucose-regulated protein 78 ( GRP78) , phosphorylated protein kinase R-like endoplasmie reticulum kinase (p-PERK), phosphorylated eukaryotic translation initiation factor 2 alpha ( p-elF2 ) , CCAAT/enhancer-binding protein homologous protein ( CHOP ) and caspase-12 in lung tissues ( by Western blot) . Apoptosis index ( AI) was calculated. Results Compared with group C, the lung injury scores, W/D ratio, AI and CO levels in plasma and lung tissues were significantly increased, and the expression of HO-1, GRP78, p-PERK, p-elF2, CHOP and caspase-12 was up-regulated in the other three groups ( P＜0. 05) . Compared with group ALI, lung injury scores, W/D ratio and AI were sig-nificantly increased, CO levels in plasma and lung tissues were decreased, the expression of HO-1 was down-regulated, and the expression of GRP78, p-PERK, p-elF2, CHOP and caspase-12 was up-regula-ted in group AZ (P＜0. 05), and no significant change was found in the parameters mentioned above in group AV ( P＞0. 05) . Conclusion HO-1/CO signaling pathway produces endogenous protection possibly through inhibiting endoplasmic reticulum stress during endotoxin-induced ALI in rats.