Role of p38 MAPK-HSP27 signaling pathway in rat acute lung injury induced by lipopolysaccharide

AIM: To observe the role of p38 mitogen-activated protein kinase (p38 MAPK)-heat-shock protein 27 (HSP27) signaling pathway in lipopolysaccharide-induced acute lung injury (ALI) in rats. METHODS: Wistar rats were randomly divided into control group, ALI group and ALI+SB203580 group. After the experimental model was established, the rats were sacrificed. The pathological changes of the lung and the changes of F-actin and G-actin in the endothelial cells were observed. The ratio of wet weight to dry weight (W/D) of the lung tissues was measured. The protein levels in bronchoalveolar lavage fluid (BALF) were detected. The levels of IL-6 and TNF-α in serum and BALF were tested. The concentrations of p-p38 and p-HSP27 in the lung were determined. RESULTS: In ALI group, the protein levels in BALF and W/D ratio of the lung increased significantly at 2 h. The levels of TNF-α and IL-6 in serum and BALF began to increase at 2 h, which had significant difference as compared with control group. Aleolar epithelial swelling, alveolar walls widening, alveolar interstitial and cavity edema, and the exudation of alveolar inflammation cells, red blood cells and protein were observed in ALI group. The protein levels in BALF and W/D ratio of the lung in ALI+SB203580 group were much less than those in ALI group. The exudation of alveolar inflammation cells, red blood cells and protein, and the interstitial and alveolar edema in ALI+SB203580 group alleviated as compared with ALI group. The expression of p-p38 MAPK and p-HSP27 in the lung at 2 h in ALI group was higher than that in control group. F-actin expression in ALI group obviously increased than that in control group at time points of 0 h and 8 h. Compared with ALI group, the expression of p-HSP27 and F-actin in ALI+SB203580 group was reduced. CONCLUSION: Lipopolysaccharide activates p38 MAPK-HSP27 signaling pathway and induces lung injury. Blockage of p38 MAPK-HSP27 signaling pathway may reduce lung injury.     

Role of p38 MAPK in cyclic mechanical stretch induced HMGB1 expression in alveolar macrophages

AIM: To investigate the role of p38 mitogen-activated protein kinase (MAPK) in cyclic mechanical stretch induced the expression of high mobility group box 1 protein (HMGB1) in alveolar macrophages (AMs). METHODS: AMs were cultured and seeded at 1×108 cells/L in 6-well Bioflex cell culture plates. Subsequently, the cells were exposed to cyclic mechanical stretch at 20% (group B) elongation using Flexercell 4000T cell stretching unit. In group C, cells were pre-treated with SB203580 (40 μmol/L) for 2 h before mechanical stretch. Group A served as control. The expression of HMGB1 mRNA in alveolar macrophages was detected by RT-PCR. p38 MAPK activity and the expression of HMGB1 protein were measured by Western blotting analysis. RESULTS: The expression of HMGB1 mRNA and protein, and the activity of p38 MAPK in AMs were significantly increased in group B than those in group A (P<0.05). SB203580, an inhibitor of p38 MAPK, significantly inhibited the inducing effect of mechanical stretch (P<0.05). CONCLUSION: Mechanical stretch regulates the expression of HMGB1 mRNA and protein in alveolar macrophages by activating p38 MAPK signal pathway.     

Anti-inflammatory effect of partial liquid ventilation on acute lung injury

AIM:To investigate the anti-inflammatory e ffect of partial liquid ventilation in the piglets with lung lavage-induced acut e lung injury.METHODS:16 piglets were treated by lung lavage to a partial pre ssure of oxygen in arterial blood (PaO2) below 100 mmHg for one hour and rando mly divided into mechanical ventilation group (MV group) and partial liquid vent ilation group (PLV group).Blood-gas analysis,hemodynamics,the contents of TNF-α,MD A,SOD,and MPO activity in lung tissue were measured.RESULTS:(1) Lung W/D,PPI and the count of WBC in the BALF in P LV group were significantly lower than those in MV group.The contents of MDA an d MPO in lung tissue in PLV group were significantly lower than those in MV grou p.However,no evident difference in SOD activity in lung tissue between two gro ups was observed.(2) The contents of TNF-α in lung tissue in PLV group were si gnificantly lower than those in MV group.CONCLUSION:Partial liquid ventilation with perfluorocarbon has anti-inflammatory effect on lung lavage-induced acute lung injury in the piglets .     

Relationship of p38MAPK,NF-κB and HO-1 in LPS-induced acute lung injury in rats

AIM: To investigate the relationship of p38 mitogen-activated protein kinases (p38MAPK), nuclear factor-kappa B (NF-κB) and heme oxygenase-1 (HO-1) in acute lung injury (ALI) in rats.METHODS: Forty male Wistar rats were divided into 5 groups (n=8) at random: control group or normal saline group (NS group), lipopolysaccharide group (LPS group), Hemin (inducer of HO-1)+LPS group, ZnPPIX (inhibitor of HO-1)+LPS group and SB203580 (inhibitor of p38MAPK)+LPS group (SB+LPS group). Six hours after endotracheal instillation of LPS or NS, the ratio of neutrophils and the protein contents in bronchoalveolar lavage fluid (BALF) of right lung, the ratio of wet/dry weight (W/D) of the superior lobe of right lung, and arterial blood gas analysis (ABG) were examined. The protein levels of p38MAPK and NF-κB in the lower lobe of right lung were detected by Western blotting. The protein expression of HO-1 in the middle lobe of right lung was measured by the method of immunohistochemisty. The structure of the lung was evaluated under light microscope. RESULTS: Compared with NS group, the ratio of neutrophils and protein contents in BALF, the ratio of W/D, the protein levels of HO-1, p38MAPK and NF-κB were obviously higher, and arterial oxygen pressure (PaO₂), partial pressure of carbon dioxide in artery (PaCO₂) and bicarbonate content (HCO^-₃) were significantly lower in LPS group, Hemin+LPS group, ZnPPIX+LPS group and SB+LPS group (P<0.05 or P<0.01). The ratio of neutrophils and proteins in BALF, the ratio of W/D, the protein levels of p38MAPK and NF-κB were significantly lower, the protein level of HO-1 was obviously higher in Hemin+LPS group and SB+LPS group than those in LPS group (P<0.05), while the changes of the parameters in ZnPPIX+LPS group were in a contrary manner (P<0.05). No significant difference of the parameters between Hemin+LPS group and SB+LPS group (P>0.05) was found. The structures of the lung tissues in LPS group were severely damaged and even severer damages were observed in ZnPPIX+LPS group. The structural changes of the lung tissues in Hemin+LPS group and SB+LPS group were slighter. CONCLUSION: p38MAPK/NF-κB and HO-1 are inhibited by each other and the effects of them are independent on the acute lung injury.     

Adipolin/CTRP12 protects against LPS-induced ARDS by up-regulating alveolar epithelial sodium channel in mice

AIM: To investigate the effect of adipolin/CTRP12 in LPS-induced acute respiratory distress syndrome(ARDS) and its potential regulation on alveolar epithelial sodium channel(ENaC) in mice. METHODS: C57BL/6J mice(n=40) were randomly divided into control group, LPS group, adipolin group and wortmannin(PI3K inhibitor) group with 10 mice in each group using random number table. The pathological changes of the lung tissues were evaluated by HE staining. The alveolar fluid clearance(AFC) was measured by Evans blue-marked albumin, and the concentrations of total protein in bronchoalveolar lavage fluid(BALF) were assessed by bicinchoninic acid(BCA) method. In BALF, the levels of IL-1β and TNF-α were determined by ELISA, and the activity of myeloperoxidase(MPO) was detected by an MPO assay kit. The total cell counts and polymorphonuclear neutrophil(PMN) counts in the BALF were analyzed by Giemsa staining. The mRNA levels of α-ENaC were assessed by qPCR, while the protein levels of α-ENaC and p-Akt were determined by Western blot. RESULTS: Compared with control group, the classic ARDS pathological changes were observed in the mice in LPS group, manifesting by severe pathological lung injury(P<0.05), increases in W/D weight ratio, total protein levels, cell counts, MPO activitiy, and IL-1β and TNF-α levels in the BALF, and decrease in AFC(P<0.05), accompanied by down-regulated levels of α-ENaC and p-Akt in the lung tissues(P<0.05). The deteriorating effects triggered by LPS were significantly reversed by administration of adipolin. However, PI3K inhibitor wortmannin canceled the beneficial effects of adipolin on LPS-induced ARDS, as evidenced by aggravated lung injury, increased levels of W/D weight ratio, protein levels, cell counts, MPO activity, and IL-1β and TNF-α levels in the BALF(P<0.05), and decreased levels of AFC, α-ENaC and p-Akt in the lung tissues. CONCLUSION: Adipolin protects against LPS-induced ARDS in the mice by up-regulating α-ENaC and enhancing AFC via PI3K/Akt signal pathway.     

Effects of Jiedu-Qingfei mixture on NF-κB and p38 MAPK pathways in lung tissues of rats with Mycoplasma pneumoniae infection

AIM: To observe the therapeutic effect of Jiedu-Qingfei mixture on Mycoplasma pneumoniae (MP)-infected rat lung tissues and to explore its mechanism. METHODS: SD rats (n=40) were randomly divided into 4 groups:blank control group, model group, Jiedu-Qingfei group and positive control group, with 10 rats in each group. The rats in experimental groups were slowly dripped with 1×10⁹ CFU/L MP solution into their nostrils for 4 d. One rat in each group was sacrificed for MP nucleic acid detection at the second day after inoculation, and the other rats were given gavage therapy. The rats in blank control group and model group were intragastrically given the same volume of normal saline, the rats in Jiedu-Qingfei group were given 8 mL/kg Jiedu-Qingfei mixture daily for 4 weeks, and the rats in psoitive control group were given dexmethasone sodium phosphate (0.5 mg·kg^-1·d^-1). After the experiment, the rats were killed. The serum and bronchoalveolar lavage fluid (BALF) were collected for detecting the levels of interleukin-12 (IL-12), IL-13 and TNF-α by ELISA. The right lung tissues were used for pathological observation and HE staining, while the left lung tissues were used to detect the expression of NF-κB p50, I-κBα and p38 mitogen-activated protein kinase (p38 MAPK) at mRNA and protein levels. RESULTS: The results of MP nucleic acid detection showed that all the rats except blank control group were MP nucleic acid positive, indicating that the rat model of MP infection was successfully established. On the 1st day of the treatment, the pathological scores of the lung tissues in model group and Jiedu-Qingfei group were significantly higher than those in blank control group (P<0.05). After treatment, the pathological scores of the lung tissues in mo-del group were significantly higher than those in blank control group and Jiedu-Qingfei group. The levels of IL-12 in the serum and BALF in model group were significantly lower than those in blank control group after MP infection (P<0.05), while those after treatment with Jiedu-Qingfei mixture were significantly higher than those in model group (P<0.05). The levels of IL-13 and TNF-α in the serum and BALF of MP-infected rats were increased significantly, while those after treatment with Jiedu-Qingfei mixture were significantly lower than those in model group (P<0.05). The mRNA expression levels of NF-κB p50 and p38 MAPK in model group were increased significantly (P<0.01). After treatment, the mRNA expression levels of NF-κB p50 and p38 MAPK were decreased significantly compared with model group (P<0.01). The mRNA expression level of I-κBα in model group was significantly lower than that in control group. After treatment, the mRNA expression of I-κBα in Jiedu-Qingfei group was significantly higher than that in model group (P<0.05). The protein levels of NF-κB p50 and p38 MAPK in the lung tissues of model group were significantly higher than those of blank control group. After treatment, the protein expression of NF-κB p50 and p38 MAPK was decreased significantly. The protein level of I-κBα in model group was significantly lower than that in blank control group, and after treatment with Jiedu-Qingfei mixture, the protein expression level of I-κBα was increased significantly (P<0.05). CONCLUSION: Jiedu-Qingfei mixture may attenuate lung tissue inflammation caused by MP through NF-κB and p38 MAPK pathways.     

Effects of mitogen activated protein kinase on γ-glutamylcysteine synthase in lung of guinea pigs with bronchial asthma

AIM: To investigate the effects of mitogen activated protein kinase on γ-glutamylcysteine synthase (γ-GCS) in lung of guinea pigs with bronchial asthma.METHODS: Twenty adult male guinea pigs were divided into asthmatic group and control group (10 in each group).Asthmatic model was established by ovalbumin intraperitoneal injection combined with inhalation.The numbers of total and inflammation cells in bronchoalveolar lavage fluid (BALF) were measured.The γ-GCS-h mRNA in lung tissue was examined by in situ hybridization and RT-PCR.Immunohistochemistry was used to detecte the expression of γ-GCS,phosphorylated extracellular signal regulated kinase (p-ERK),phosphrylated c-Jun amino terminal kinase (p-JNK) and phosphorylated p38 (p-p38) in lung tissues.Western blotting was conducted to determine the expressions of p-ERK,p-JNK and p-p38 in lung tissue.The activity of γ-GCS was measured by coupled enzyme assay.RESULTS: (1) The total cell number and number of eosinophils in BALF of asthmatic group were significantly higher than those in control group (P<0.01).(2) Immunohistochemistry indicated that the p-ERK,p-p38,p-JNK and γ-GCS were stronger expressed in asthmatic group than those in control group (P<0.01).Western blotting also discovered that the expressions of p-ERK,p-JNK and p-p38 in lung tissue of asthmatic group were stronger than those in control group.(3) Both in situ hybridization and RT-PCR analysis showed that the expression of γ-GCS-h mRNA was more positive in asthmatic group compared with control group (P <0.01).(4) The activity of γ-GCS of asthmatic group was significantly higher than that in control group (P<0.01).(5) Linear correlation analysis indicated that in lung tissue of guinea pig with asthma,p-ERK and p-p38 markedly positive correlated with γ-GCS-h mRAN and γ-GCS protein.No relationship between p-JNK and γ-GCS-h mRAN,γ-GCS protein was observed.CONCLUSION: The expressions of p-ERK,p-p38,p-JNK and γ-GCS increase in lung of guinea pigs with bronchial asthma.p-ERK and p-p38 may positively regulate the expression of γ-GCS.     

Role of neutrophil elastase and myeloperoxidase in asthma of rats

AIM:To observe the changes of polymorphonuclear leukocytes (PMN), neutrophil elastase (NE) and myeloperoxidase (MPO) expression in rat asthma. METHODS:Eighteen rats were randomly divided into two groups on average, including asthma group and control group. The rat model of asthma was established by the ovalbumin (OVA) challenge methods. Blood PMN were isolated andpurified. The protein expression of MPO were detected by immunohistochemistry and chromatometry techniques. NE was detected by ELISA. RESULTS:(1) Immunohistochemistry showed that the levels of MPO expression around bronchus and in purified PMN in asthma group were significantly increased compared with those in control group (P<0.01). Activities of MPO were significantly increased in bronchoalveolar lavage fluid (BALF) and lung tissue in asthma group compared with those in control group (P<0.05, P<0.01). (2) Levels of NE were significantly increased in BALF and PMN in asthma group compared with control group (P<0.01). (3) Number of PMN were significantly higher in BALF, bronchus and lung tissue in asthma group than those in control group (P<0.01). CONCLUSION:Levels of PMN counting and expression of MPO and NEare significantly increased in experimental asthma rats. PMN may be involved in inflammation in asthma via increasing the levels of NE and MPO.     

Protective role of endogenous hydrogen sulfide in cholecystokinin octapeptid against acute lung injury induced by lipopolysaccharide

AIM: To explore the role of endogenous hydrogen sulfide (H₂S) in the mechanism of cholecystokinin octapeptide (CCK-8) to alleviate acute lung injury (ALI) induced by lipopolysaccharide (LPS). METHODS: Eighty-four Sprague-Dawley rats were randomly divided into seven groups: control, LPS (instilled intratracheally to reproduce the model of ALI), NaHS (H₂S donor) +LPS, propargylglycine ［inhibitor of cysathionine-γ-lyase (CSE), PPG］+LPS, CCK-8+LPS, PPG+CCK-8+LPS and CCK-8 group. Animals were sacrificed at 4 h and 8 h after agent instillation. The wet and dry ratio (W/D) of the lung weight was measured and calculated. Morphological changes of lung tissues were observed. H₂S concentration in plasma, malondialdehyde (MDA) content, myeloperoxidase (MPO) and CSE activities in the lung were determined. Furthermore, the level of P-selectin of lung tissue was measured by radioimmunoassay, the CSE mRNA expression in the lung was detected by RT-PCR, and the protein content in bronchoalveolar lavage fluid (BALF) was detected. RESULTS: Compared with control, severe injury of lung tissues and increase in W/D, protein content in BALF, MDA content, MPO activity and P-selectin level in the lung were observed in rats treated with LPS. LPS also lead to a drop in plasma H₂S concentration, lung CSE activity and CSE mRNA expression. Administration of NaHS before LPS could attenuate the changes induced by LPS, while H₂S concentration, CSE activity and CSE mRNA expression were higher than those in LPS group. However, pre-treatment with PPG exacerbated the lung injury induced by LPS, H₂S concentration, CSE activity and CSE mRNA expression were lower than those in LPS and CCK-8 +LPS group, respectively. CONCLUSION: CCK-8 attenuates LPS-induced acute lung injury by means of anti-oxidation and inhibition of PMN adhesion and aggregation, both of which are mediated by endogenous H₂S.     

Protective effects and mechanism of astragalus injection on asthmatic rats

AIM: To explore the protective effects and mechanism of astragalus injection on asthmatic rats.METHODS: OVA was injected intraperitoneally and inhaled to produce the asthmatic model.Forty rats were randomly divided into five groups: control group,asthma group and astragalus groups of high,medium and low dose.The concentrations of IL-4,IFN-γ in BALF,the expression of IL-4 mRNA,IFN-γ mRNA and phospho-p38 MAPK in lung tissues were respectively measured by ELISA,RT-PCR and Western blotting.The number of inflammatory cells in BALF and histropathology changes were observed.RESULTS: In asthmatic group,the number of inflammatory cells and the concentrations of IL-4 in BALF and the expression of IL-4 mRNA,phospho-p38 MAPK in lung tissue were higher,but IFN-γ and IFN-γ mRNA were lower than those in normal control rats (P<0.01).In astragalus group,the number of inflammatory cells,the concentrations of IL-4 in BALF and the expression of IL-4 mRNA,phospho-p38 MAPK in lung tissue were lower,but IFN-γ and IFN-γ mRNA were higher than those in normal control rats (P<0.01),and histropathology damage was alleviated significantly.The efficacies in the astragalus groups of high,medium and low dose were similar,which no significant difference was observed among them.There were positive correlations between the expression of 〖JP3〗phospho-p38 MAPK and the number of eosinophil,the concentration of IL-4,IL-4 mRNA (r=0.63,r=0.69,r=0.71,〖JP〗 P<0.01),and negative correlations between the expression of phospho-p38 MAPK and IFN-γ and IFN-γ mRNA (r=-0.65,r=-0.68,P<0.01).CONCLUSION: p38 MAPK may play a role in pathological process of asthma.Astragalus effectively treats asthma by inhibiting the expression of phospho-p38 MAPK,correcting the inbalance of IFN-γ/ IL-4 and decreasing the number of inflammatory cells.     

Effect of mesenteric lymph duct ligation on actue lung injury in rats

AIM：To explore the effect of mesenteric lymph duct ligation against actue lung injury (ALI) in rats.METHODS：45 Wistar rats were divided into three groups：the ligation group,the non-ligation group and sham operated group,and the two-hit model was established by hemorrhage and LPS injection.Mesenteric lymph was diverted by ligating mesenteric lymph duct in ligation group.All rats facilitated blood withdrawal for blood sample to arterial gas analysis after 24 hours.Then the WBC,NO,NOS,MDA,SOD and lung permeability index (LPI) were determined in bronchoalveolar lavage fluid (BALF),the MPO and ATPase activity were determined in lung homogenate.The ultrastructure was also observed.RESULTS：After two-hit,the PaCO2,the total cells and PMN,the NO2-/NO3-,NOS and MDA content in BALF and MPO activity in lung homogenate and LPI in non-ligation group were significantly increased than those in sham operated group.PaO2 and pH in arterial blood,SOD in BALF and the ATPase in lung homogenate were significantly lower (P<0.01 or P<0.05).The total cells and PMN,MDA,NO2-/NO3- in BALF,LPI in ligation group were significantly increased than those in sham operated group,and SOD in BALF was significantly lower (P<0.01 or P<0.05).The pH and PaO2 in arterial blood,the ATPase in lung homogenate in ligation group were significantly increased than those in non-ligation group,and the PaCO2,the total cells,PMN,NO2-/NO3-,NOS,MDA in BALF,LPI,and MPO in lung homogenate in ligation group were significantly lower than those in non-ligation group (P<0.01 or P<0.05).The injury of pulmonary vascular endothelium in ligation group was lighter than that in non-ligation group.CONCLUSION：The ligation of mesenteric lymph duct attenuates the ALI of rats.Mesenteric lymph might play an important role in the pathogenesis of ALI.     

Bone marrow-derived mesenchymal stem cell-conditioned medium atte-nuates LPS-induced acute lung injury in mice

AIM:To explore the effects of bone marrow-derived mesenchymal stem cells-conditioned medium (MSCs CdM) on lipopolysaccharide (LPS)-induced acute lung injury. METHODS:Lung injury was induced in mice by intraperitoneal injection of LPS. The mice were given a tail vein injection of MSCs CdM or normal saline 1 h after LPS administration. The mice were killed by an intraperitoneal injection of pentobarbital 6 h after LPS injection for either bronchoalveolar lavage fluid (BALF) and serum collection or lung histological analysis. RESULTS:Compared with control group, the BALF levels of protein, interleukin-10 (IL-10) and keratinocyte growth factor (KGF), the serum levels of tumor necrosis factor α (TNF-α) and IL-6, and the myeloperoxidase (MOP) activity in the lung tissues were significantly higher in LPS group, and severe pathological damages in the lung tissues were also observed. Treatment with MSCs CdM significantly reduced the BALF prtein level, the seum TNF-α and IL-6　levels and the lung MPO activity, and attenuated the lung pathological damages, but further increased the levels of IL-10 and KGF in the BALF. CONCLUSION:Treatment with MSCs CdM attenuates the lung injuries induced by LPS, which may be via regulating the expression of TNF-α, IL-6, IL-10 and KGF.     

Meconium induces formation of nitrotyrosine and expression of inducible nitric oxide synthase in the rat lung

AIM: To evaluate the contribution of inducible nitric oxide synthase (iNOS) and nitrotyrosine to acute lung injury (ALI) in rats with meconium aspiration. METHODS: 16 health male Sprage-Dawley rats were randomized to control group and meconium group, followed by intratracheally administration of 1 mL/kg saline or 1 mL/kg 20% human newborn meconium suspension. The animals were killed after 24 h of treatment. The measurements included bronchoalveolar lavage fluid (BALF) cell count, pulmonary myoloperoxidase (MPO) activity and nitric oxide (NO) level. Western bloting was used to determine the expression of pulmonary nitrotyrosine-a specific “footprint” of peroxynitrite and iNOS. RESULTS: Compared to control group, the rats in the meconium group had increased BALF cell counts ［(4.04±1.01)×109cells/L vs （0.53±0.19)×109cells/L］, pulmonary MPO activity ［(1.49±0.22）U/g wet lung tissue vs (0.62±0.16) U/g wet lung tissue］, NO level ［(12.77±5.00） mmol/g protein vs （4.89±1.32) mmol/g protein］, increased expression of nitrotyrosine and iNOS (0.46±0.19 and 1.49±0.60 vs 0.15±0.04 and 0.09±0.04, respectively), all P<0.01. CONCLUSIONS: Meconium results in an increase in expression of pulmonary iNOS, leading to over production of NO and nitrotyrosine, which may be of pathogenic importance in the ALI with meconium aspiration.     

Clonidine inhibits inflammatory response in lung injury mice through cholinergic anti-inflammatory pathway

AIM:To explore the influence of clonidine on inflammatory response in lung injury mice and its possible mechanism.METHODS:Clonidine solution was intravenously injected into the mice with lung injury induced by LPS.The left upper lobe of the lung was collected to detect lung wet/dry weight ratio (W/D) and total lung water content (TLW).The concentrations of IL-6,IL-1β and TNF-α were measured by ELISA.The expression of α7 nicotinic acetylcholine receptor (α7nAChR) and high-mobility group box protein 1(HMGB1) at mRNA and protein levels was determined by RT-PCR and Western blot.After importing α7nAChR siRNA lentiviral vector or injecting exogenous HMGB1 protein,the inflammatory cytokines were detected.RESULTS:Clonidine attenuated lung injury and inhibited inflammatory reaction.Clonidine promoted the activation of cholinergic anti-inflammatory pathway by promoting α7nAChR expression.Clonidine inhibited HMGB1 expression,which promoted the secretion of IL-6,IL-1β and TNF-α.HMGB1 was negatively regulated by α7nAChR.CONCLUSION:Clonidine functions as an anti-inflammatory reagent to the lung injury mice.The mechanism may be related to activating the cholinergic anti-inflammatory pathway and inhibiting the expression of HMGB1.     

Effect of curcumin on learning-memory ability and expression of HMGB1 and JNK in rat model of Alzheimer disease

AIM: To evaluate the effect of curcumin on impaired learning-memory ability and the expression of high mobility group box protein 1 (HMGB1) and c-Jun N-terminal kinase (JNK) in a rat model of Alzheimer disease (AD). METHODS: Male Sprague-Dawley rats, weighing 250~270 g, were randomly divided into 4 groups (n=9): blank control group (group A), model group (group B), curcumin treatment group (group C, curcumin injected intraperitoneally at 100 mg·kg-1·d-1 for 6 consecutive days) and solvent control group (group D). The rats of AD model were induced by injection of ibotenic acid into the nucleus basalis of Meynert (NBM) bilaterally. All rats were trained in Morris maze to assess the ability of learning and memory. The expression of HMGB1 and JNK in the hippocampus was detected by the methods of immunohistochemistry and Western blotting. RESULTS: Compared with group A, the average escape latency (AEL) in groups B and D were obviously longer (P<0.05), while AEL in group C in the 5th and 6th days were significantly shorter (P<0.05). The releases of HMGB1 in the CA1 and CA3 areas in groups B and D from the nucleus were abundant. Compared with groups B and D, HMGB1 in hippocampal CA1 and CA3 areas in group C secreted out of the nucleus decreased obviously (P<0.05). No significant difference of the release of HMGB1 between group A and group C was observed (P>0.05). No significant difference in the expression of HMGB1 in the hippocampus among the 4 groups was found (P>0.05). However, compared with groups B and D, the expression of JNK in group C was decreased obviously (P<0.05). CONCLUSION: Curcumin significantly improves the learning and memory ability of AD rats. The probable mechanisms may be related to inhibiting the release of HMGB1 from the nucleus of hippocampal neurons and decreasing the expression of JNK in the hippocampus.     

Effect of HMGB2 on cell cycle and proliferation of lung adenocarcinoma

AIM: To investigate the effect of high-mobility group protein B2 (HMGB2) on cell cycle and proliferation of lung adenocarcinoma cells. METHODS: Cancer RNA-Seq Nexus (CRN) was used to analyze HMGB2 expression in lung adenocarcinoma tissues. OncoLnc was used to analyze the correlation between HMGB2 and prognosis of lung adenocarcinoma patients. Cancer Single-cell State Atlas (CancerSEA) was used to analyze the correlation between HMGB2 and 14 kinds of functional states of lung adenocarcinoma. siRNA was used to inhibit HMGB2 expression in human lung adenocarcinoma A549 cells. The silencing effects were verified by real-time PCR and Western blot, and the cell proliferation was detected by CCK8 and EdU assays. RESULTS: HMGB2 was over-expressed in the lung adenocarcinoma tissues. The overall survival of the patients with lung adenocarcinoma in HMGB2 high expression group was significantly lower than that of the patients with low expression of HMGB2 (log-rank test P=0.017 3). HMGB2 expression was positively correlated with cell cycle and proliferation of lung adenocarcinoma cells. The viability and proliferation ability of A549 cells after HMGB2 expression knock-down were significantly reduced (P < 0.05). CONCLUSION: The expression of HMGB2 is positively correlated with the cell cycle and proliferation of lung adenocarcinoma, and it can be used as a potential marker for evaluating the prognosis and therapeutic target of patients with lung adenocarcinoma.     

Mechanisms for protection of berberine against LPS-induced acute lung injury in mice

AIM:To investigate the mechanisms by which berberine attenuates LPS-induced acute lung injury, and provide a new strategy for the treatment of the lung injury due to LPS. METHODS:BALB/c mice were randomly assigned into three groups (control, LPS group, and berberine treatment group). Mice were administered intragastrically with distilled water (0.1 mL/10 g) or neutral sulfate berberine (50 mg/kg) once a day for 3 days, 1 h after intragastrical treatment on day 3, LPS (20 mg/kg) or normal saline was injected intraperitoneally (ip). All animals were sacrificed 12 h after LPS injection, the left lung tissue sections were prepared for histology analysis and the right lung were used to determine the ratio of wet to dry lung tissue weight (W/D). In another experiment, bronchoalveolar lavage fluid (BALF) was collected, and then the total protein content, and the amounts of white blood cells (WBC) and polymorphonuclear neutrophils (PMN) in BALF were determined. Furthermore, the phosphorylation of cytosolic phospholipase A₂ (cPLA₂) was detected with immunohistochemical analysis by using phospho-cPLA2(Ser505) antibody, and the contents of thromboxane B₂ (TXB₂) in BALF, malondialdehyde (MDA) in the lungs, and activity of superoxide dismutase (SOD) in lung tissues were also determined.RESULTS:LPS induced acute lung injury, activated cPLA₂, and increased TXB₂ content in the BALF and MDA level in the lung tissue. The pretreatment with berberine significantly attenuated lung injury, lung edema and protein leakage induced by intraperitoneal injection of LPS. The expression of phospho-cPLA₂ in the lung tissues and TXB₂ content in the BALF in the berberine treatment group were lower than those in LPS group (P<0.05). In addition, the content of MDA in the lung tissue was lower in the berberine treatment group than LPS group (P<0.05), but there was no significant difference in activity of lung SOD between the berberine treatment and LPS group (P>0.05). CONCLUSION:Pretreatment with berberine remarkably reduces the LPS-induced lung injury, which is, at least in part, through inhibiting phosphorylation of cPLA₂ and decreasing lipid peroxidation. These findings provide a new strategy for the prevention and treatment of LPS-induced acute lung injury.     

Protective effect of N-acetylcysteine on mice with acute lung injury induced by H9N2 swine influenza virus

AIM: To investigate the effects of N-acetylcysteine (NAC) on acute lung injury induced by H9N2 swine influenza virus (SIV) in mice. METHODS: BALB/c mice were used to establish the animal model of acute lung injury by nasal inoculation of H9N2 SIV. The mice were divided into control group (without SIV infection), H9N2 SIV group (inoculation of H9N2 SIV) and NAC group (inoculation of H9N2 SIV plus pretreatment with NAC). The pulmonary edema was evaluated by determining the lung wet weight/dry weight (W/D) ratio. The pathological changes of the lung tissues were observed. The concontrations of TNF-α, IL-1β and IL-6 in bronchoalveolar lavage fluid (BALF) were measured.The virus titer, T-SOD activity, MPO activity and MDA content in the homogenate of the lung tissues were detected. RESULTS: Treatment with NAC decreased the morality of infected mice, and significantly prolonged the survival time of infected mice. The pathological changes of the lung tissues, the lung W/D ratio and the lung index were relieved when SIV infected the mice treated with NAC. Treatment with NAC significantly decreased the infiltration of inflammatory cells including macrophages, lymphocytes and neutrophils in the BALF. The levels of TNF-α, IL-6, IL-1β and MDA and the activity of MPO were also decreased. Treatment with NAC also significantly increased the T-SOD activity. CONCLUSION: The protective effect of NAC on the acute lung injury mouse model is related to suppression of the oxidative stress and inflammatory responses.     

Glyburide reduces PFOS-induced lung injury in young rats through inhibiting NLRP3 inflammasome

AIM: To explore the possible mechanism of NLR family Pyrin domain-containing protein 3 (NLRP3) inflammasome involved in perfluorooctane sulfonate (PFOS)-induced lung injury in young rats. METHODS: Twenty-eight SD rats (21-day-old) were randomly divided into control (C) group, PFOS (P) group, glyburide (G) group and glyburide + PFOS (GP) group. PFOS exposure model and glyburide protection model were established. The lung specimens were collected for HE staining. The levels of myeloperoxidase (MPO) in the lung tissues, interleukin-1β (IL-1β) and interleukin-18 (IL-18) in the bronchoalveolar lavage fluid (BALF) were measured by ELISA. The concentration of PFOS in serum was measured by high-performance liquid chromatography (HPLC). The protein expression of NLRP3, caspase-1 and apoptosis-associated speck-like protein containing CARD (ASC) in the lung tissues was determined by Wes-tern blot. RESULTS: HE staining of lung tissues showed that compared with the control rats, there were obvious inflammatory infiltration in trachea and alveolar interstitium of the rats in P group. Glyburide reduced the inflammatory responses significantly. ELISA results showed that the level of MPO in the lung tissues of the rats in P group was higher than those in other 3 groups (P<0.05). The levels of IL-1β and IL-18 in the BALF of the rats in P group were significantly higher than those in control group and GP group (P<0.05). The results of Western blot showed that the protein levels of NLRP3, caspase-1 and ASC in P group were significantly higher than those in control group and GP group (P<0.01). Immunohistochemical staining results showed that compared with the other 3 groups, the expression of NLRP3 in P group was significantly increased (P<0.01). CONCLUSION: PFOS exposure may lead to lung injury in rats by activating NLRP3 inflammasome and then triggering inflammation, releasing inflammatory factors such as IL-1β. Glyburide specifically inhibits the assembly of NLRP3 inflammasome, suppresses the inflammatory responses and reduces the toxicity of PFOS in lung.