Ulinastatin protects rat pulmonary tissues from paraquat-induced acute injury

AIM: To investigate the protective effects of ulinastatin on the rats with paraquat-induced acute lung injury and its mechanisms. METHODS: The Wistar rats (n=108) were randomly divided into control group, paraquat group and ulinastatin group. The rats in paraquat group and ulinastatin group were given paraquat by gavage, while the rats in control group were given sterile saline by gavage. The rats in ulinastatin group were also given ulinastatin treatment. The serum levels of MDA, SOD, IL-6, IL-10 and TNF-α were measured after 1 d, 3 d, 7 d, 14 d, 21 d and 28 d. The expression levels of p38 MAPK, MMP-2 and TIMP-1 in the lung were also measured. RESULTS: The levels of SOD in 1 d, 3 d and 7 d in paraquat group and ulinastatin group were significantly lower than those in control group (P<0.01). The level of SOD in ulinastatin group was significantly higher than that in paraquat group (P<0.05). The levels of MDA, IL-6, IL-10 and TNF-α in 1 d, 3 d and 7 d in paraquat group and ulinastatin group increased compared with control group (P<0.01), and those in ulinastatin group were significantly lower than those in paraquat group (P<0.05). The levels of p38 MAPK and TIMP-1 in 1 d, 3 d, 7 d, 14 d, 21 d and 28 d in paraquat group and ulinastatin group were higher than those in control group (P<0.01), and those in ulinastatin group was significantly lower than those in paraquat group (P<0.05). The level of MMP-2 in 1 d, 3 d, 7 d, 14 d and 21 d in paraquat group and ulinastatin group increased compared with control group (P<0.01), and that in ulinastatin group was significantly lower than that in paraquat group (P<0.05).CONCLUSION: Ulinastatin protects the lung tissues of rats from paraquat-induced acute lung injury by inhibiting p38 MAPK signaling pathway and ameliorating inflammatory and oxidative responses.     

Dexmedetomidine attenuates acute kidney injury induced by hemorrhagic shock/resuscitation in rats

AIM: To investigate the effects of dexmedetomidine on hemorrhagic shock/resuscitation (HS/R)-induced acute kidney injury (AKI) in rats, and to explore the possible mechanisms. METHODS: Wistar rats (n=32) were randomly divided into 4 groups (n=8):normal saline control group (NS group), dexmedetomidine group (D group), HS/R group and HS/R+D group. The animals were sacrificed at 6 h after resuscitation. The levels of serum creatinine (Cr) and blood urine nitrogen (BUN) were examined. The kidneys of all rats were removed for evaluation of histological characteristics, and the levels of malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and superoxide dismutase (SOD) were measured. The expression of nuclear factor-κB (NF-κB) and hemeoxygenase-1 (HO-1) was determined by Western blot. RESULTS: Compared with NS group, the levels of Cr, BUN, MDA, TNF-α and IL-1β were obviously increased in HS/R group, which were obviously decreased in HS/R+D group (P<0.05). Compared with NS group, the SOD activity was obviously decreased in HS/R group, which was obviously increased in HS/R+D group (P<0.05). Compared with NS group, the protein expression of NF-κB was obviously increased in HS/R group, which was obviously decreased in HS/R+D group (P<0.05). Compared with NS group, the protein expression of HO-1 was increased in HS/R group. Compared with HS/R group, the protein expression of HO-1 was obviously increased in HS/R+D group. Compared with NS group, HS/R induced marked kidney histological injury, which was less pronounced in HS/R+D group.CONCLUSION: Dexmedetomidine effectively protects rats against AKI caused by HS/R, and its mechanism may be associated with the increase in HO-1 expression and the inhibition of NF-κB expression.     

Regulation of ectopic trypsin and proinflammatory cytokine expression by NF-κB and AP-1 in influenza A virus induced myocarditis

AIM: To investigate the regulatory effects of nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) on the expression of ectopic trypsin and proinflammatory cytokines in influenza A virus (IAV)-induced myocarditis. METHODS: Male BALB/c mice of 8 weeks old (n=40) were randomly divided into 4 groups: normal control group (NC), infection control group (IC), NF-κB inhibitor group (NI) and AP-1 inhibitor group (AI). The mice in NC group and IC group were instilled intranasally with 15 μL saline and 40 plaque forming units (PFU) IAV, respectively. The mice in NI group and AI group were infected intranasally with 40 PFU IAV and injected intraperitoneally with 10 mg/kg NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) or 2.5 mg/kg AP-1 inhibitor nordihydroguaiaretic acid (NDGA) once daily. The mice were euthanized at day 9 after instillation, and the hearts were removed for pathological and biochemical analysis. RESULTS: IAV infection induced significant up-regulation of ectopic trypsin, and proinflammatory cytokines interleukin 6 (IL-6), IL-1β and tumor necrosis factor-α (TNF-α) in the myocardium, and triggered acute myocarditis. PDTC significantly inhibited NF-κB activation and up-regulation of ectopic trypsin and proinflammatory cytokines, and effectively suppressed IAV replication and myocardial inflammatory response (P<0.01). NDGA effectively inhibited AP-1 activity (P<0.01) and mildly suppressed up-regulation of proinflammatory cytokines (P<0.05), but had no effects on the expression of ectopic trypsin, IAV replication and the extent of myocarditis (P>0.05). CONCLUSION: IAV infection induces up-regulation of ectopic trypsin and proinflammatory cytokines in myocardium predominantly by the activation of NF-κB. AP-1 signaling pathway might be only partially involved in the regulation of proinflammatory cytokines.     

Sphingosine-1-phosphate receptor-2 attenuates lipopolysaccharide-induced acute lung injury

AIM: To investigate the effects and mechanisms of sphingosine-1-phosphate receptor-2 (S1P2R)on lipopolysaccharide (LPS)-induced acute lung injury (ALI). METHODS: ALI model was induced by intratracheal administration of LPS in both wild-type mice and S1P2R -deficient mice. The pathological changes in the lung tissues were observed, and the protein concentration, total cell number, neutrophil ratio, TNF-α level and IL-6 level were determined in the bronchoalveolar lavage fluid (BALF) 24 h after LPS injection. In order to investigate the mechanisms of S1P2R in LPS-induced ALI, 10 min before LPS injection, both wild-type mice and S1P2R -deficient mice were injected with nitric oxide synthase inhibitor by tail vein injection, the pathological changes of the lung tissues were observed, and the protein concentration and total cell number in BALF were determined 12 h after LPS injection. RESULTS: Compared with wild-type mice, S1P2R -deficient mice showed more severe LPS-induced ALI, and the protein concentration, neutrophils and inflammatory cytokines in BALF were significantly increased in S1P2R -deficient mice. Administration of nitric oxide synthase inhibitor N^ω-L-nitro-arginine methyl ester protected S1P2R -deficient mice from aggravation of ALI. CONCLUSION: S1P2R mediates the protection from LPS-induced ALI possibly through inhibiting nitric oxide synthase.     

Dexmedetomidine attenuates acute alcoholic hepatic injury in mice

AIM: To investigate the effects of dexmedetomidine (DEX) on acute alcoholic hepatic injury in mice and to explore the possible mechanisms. METHODS: Kunming mice (n=50) were randomly divided into 5 groups (n=10): normal saline control (NS) group, acute alcoholic hepatic injury model (E) group, low-dose (10 μg/kg) DEX (E+L) group, medium-dose (50 μg/kg) DEX (E+M) group and high-dose (100 μg/kg) DEX (E+H) group. The animals were sacrificed at 6 h after gavage of alcohol or normal saline. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD) were measured. The livers were removed for evaluation of histological characteristics and determining the content of tumor necrosis factor-α (TNF-α) amd interleukin-1β (IL-1β) in the liver tissues by ELISA. The expression levels of cytochrome P450 2E1 (CYP2E1) and nuclear factor-κB (NF-κB) in the liver tissues were evaluated by Western blot. RESULTS: Compared with NS group, the levels of ALT, AST and TG were obviously increased in E group, which were obviously decreased in E+M and E+H groups. Compared with NS group, the levels of TNF-α, IL-1β and MDA were obviously increase in E group, which were obviously decreased in E+M and E+H groups. Compared with NS group, the activity of SOD and the content of GSH were obviously decreased in E group, which were obviously increased in E+M and E+H groups. Compared with NS group, the expression of CYP2E1 and NF-κB was obviously increase in E group, which was obviously decreased in E+M and E+H groups. Compared with NS group, ethanol induced marked liver histological injury, which was less pronounced in E+M and E+H groups. CONCLUSION: DEX has a protective effect on mouse liver with acute alcoholic injury by the involvement in the processes of antioxidation and antiinflammation, and its mechanism may be associated with the inhibition of CYP2E1 and NF-κB expression.     

Angiotensin-(1-7)/Mas receptor axis protects cardiomyocytes against high glucose-induced injury by modulating nuclear factor-κB pathway

AIM: To study whether the angiotensin-(1-7)[Ang-(1-7)]/Mas receptor axis protects cardiomyocytes against high glucose(HG)-induced injury by inhibiting nuclear factor-κB(NF-κB) pathway. METHODS: The cell viability was measured by CCK-8 assay. The intracellular levels of reactive oxygen species(ROS) were detected by DCFH-DA staining. The number of apoptotic cells was tested by Hoechst 33258 nuclear staining. Mitochondrial membrane potential(MMP) was examined by JC-1 staining. The levels of NF-κB p65 subunit and cleaved caspase-3 protein were determined by Western blotting. RESULTS: Treatment of H9c2 cardiac cells with 35 mmol/L glucose(HG) for 30, 60, 90, 120 and 150 min significantly enhanced the levels of phosphorated(p) NF-κB p65, peaking at 60 min. Co-treatment of the cells with 1 μmol/L Ang-(1-7) and HG for 60 min attenuated the up-regulation of p-NF-κB p65 induced by HG. Co-treatment of the cells with Ang-(1-7) at concentrations of 0.1~30 μmol/L and HG for 24 h inhibited HG-induced cytotoxicity, evidenced by an increase in cell viability. On the other hand, 1 μmol/L Ang-(1-7) ameliorated HG-induced apoptosis, oxidative stress and mitochondrial damage, indicated by decreases in the number of apoptotic cells, cleaved caspase-3 level, ROS generation and MMP loss. However, the above cardioprotective effects of Ang-(1-7) were markedly blocked by A-779, an antagonist of Ang-(1-7) receptor(Mas receptor). Similarly, co-treatment of H9c2 cardiac cells with 100 μmol/L PDTC(an inhibitor of NF-κB) and HG for 24 h also obviously reduced the above injuries induced by HG. CONCLUSION: Ang-(1-7)/Mas receptor axis prevents the cardiomyocytes from the HG-induced injury by inhibiting NF-κB pathway.     

Effect of inhaled nitric oxide on aquaporin expression in newborn rat lung in acute hyperoxic lung injury

AIM:To investigate the effect of inhaled nitric oxide on aquaporin expression and alveolar epithelial fluid transport in newborn rats with acute hyperoxic lung injury. METHODS:32 newborn SD rats were randomized to breathe for 48 h room air (C), >95%O₂ (O), >95%O₂+10^-5 NO (NO only in the first 24 h, ONO), room air + NO (CN). Then, the rats were killed, the lung wet-to-dry weight ratio (Q_W/Q_D), the histology, and AQP1, AQP5, α₁-NKA, α-ENaC mRNA expressions in the lungs were measured. RESULTS:Compared with C group, the Q_W/Q_D in O group significantly increased (P<0.01), and AQP1 mRNA expression decreased significantly (P<0.01). Compared with O group, ONO group had a lower level of Q_W/Q_D (P<0.05), and AQP1 mRNA expression increased (P<0.05). AQP5 mRNA expression in all groups remained unchanged. CONCLUSION:In newborn rats with acute hyperoxic lung injury, inhaled 10-5 nitric oxide for 24 h may attenuate lung edema and increase AQP1 mRNA expression, suggesting that inhaled 10^-5 nitric oxide for 24 h may promote the AQP1 expression in lung in this model of acute lung injury.     

Effects of caveolin-1 scaffolding domain peptide on LPS-induced acute lung injury in mice

AIM: To investigate the effects of caveolin-1 (Cav-1) scaffolding domain peptide, cavtratin, on lipopolysaccharide (LPS)-induced mouse acute lung injury and heme oxygenase-1 (HO-1) activity. METHODS: Adult male BALB/c mice were randomly divided into 6 groups (n=8 to 10):control, Antennapedia internalization sequence (AP), LPS, LPS+hemin, LPS+ hemin+cavtratin and LPS+hemin+cavtratin+zinc protoporphyrin IX (ZnPP) groups. After LPS administration for 24 h, the lung pathological changes, the wet/dry weight (W/D) ratio of lung tissues, total cell number in bronchoalveolar lavage fluid and serum lactate dehydrogenase activity were measured. The co-localization of HO-1 and Cav-1 was displayed by immunofluorescence, and the HO-1 activity were detected. The mRNA expression of pro-inflammatory cytokines IL-1β, IL-6, TNF-α, MCP-1 and iNOS was detected by real-time PCR. RESULTS: The mice in LPS+hemin+cavtratin group had the decreased interaction between HO-1 and Cav-1, and the increased HO-1 activity compare with LPS group (P<0.05). Compared with LPS group, the pulmonary damage was attenuated in LPS+hemin+cavtratin group, and the injury indexes, including W/D ratio, total cell number in bronchoalveolar lavage fluid and lactate dehydrogenase activity in the serum, and the mRNA expression of inflammatory cytokines all decreased (P<0.05). HO-1 activity inhibitor ZnPP abolished the above protective effect of cavtratin on the lung tissues with LPS-induced acute lung injury. CONCLUSION: Cavtratin has beneficial effects on the lung with LPS-induced acute injury by restoring the HO-1 activity.     

Protective effect of dexmedetomidine-ulinastatin combination on lipopolysaccharide-induced acute lung injury in rats

AIM：To investigate the effects of dexmedetomidine-ulinastatin combination on acute lung injury induced by lipopolysaccharide (LPS) in rats. METHODS：Male Wistar rats were randomly divided into 5 groups: saline control group (NS group) was given saline (5 mL/kg, iv) alone; LPS group (L group) was given LPS (10 mg/kg, over 10 min); dexmedetomidine+LPS group (L+D group) was treated with the additional administration of dexmedetomidine (1 μg·kg -1·h -1) immediately after LPS injection; ulinastatin+LPS group (L+U group) was treated with the addi-tional administration of ulinastatin (50 000 U/kg, ip) immediately after LPS injection; dexmedetomidine+ulinastatin+LPS group (L+D+U group) received dexmedetomidine (1 μg·kg -1·h -1) and ulinastatin (50 000 U/kg) immediately after LPS injection. The animals were sacrificed at 6 h after LPS or NS administration. Partial pressure of arterial oxygen (PaO 2), pH and base excess (BE) were measured, and the lungs were removed for evaluation of histological characteristics and determining the concentrations of TNF-α, IL-1β, macrophage inflammatory protein 2 (MIP-2), malondialdehyde (MDA), nitric oxide (NO), prostaglandin E 2 (PGE 2) and myeloperoxidase (MPO) in lung tissues, lung wet/dry weight ratio (W/D), and albumin in brochoalveolar lavage fluid (BLAF). The pulmonary expression of nuclear factor kappa B (NF-κB) p65 was evaluated by Western blotting. RESULTS：Compared with NS group, PaO 2, pH and BE was lower in L group, which was increased by treatment with dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone. Compared with NS group, LPS induced marked lung histological injury, which was less pronounced in the animals treated with dexmedetomidine-ulinastatin combination but not dexmedetomidine or ulinastatin alone. The levels of IL-1β, IL-6, MIP-2, MDA, NO and PGE 2 in the lung tissues increased in L group compared with NS group, which were reduced by dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone. The MPO activity, MDA level and W/D increased in the lung tissues in L group compared with NS group, which was reduced by dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone. Compared with NS group, the albumin concentration in the BLAF increased, which was reduced by dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone. Compared with NS group, the expression of NF-κB p65 increased in L group, which was reduced by dexmedetomidine-ulinastatin combination but not by dexmedetomidine or ulinastatin alone.CONCLUSION：Dexmedetomidine-ulinastatin combination has a protective effect on LPS-induced acute lung injury in the rats.     

An animal model of acute lung injury induced by left ventricular ischemia-reperfusion

AIM: To establish a method of making acute lung injury model induced by left ventricular ischemia-reperfusion.METHODS: Forty New Zealand rabbits were randomly divided into model group (MG) and control group (CG). The left ventricular ischemia-reperfusion was established by ligaturing and loosing the anterior descending branch of the left coronary artery in the rabbits in MG group. The electrocardiogram, the phrenic nerve discharge curve, the ultrastructure and histological analysis of the lung tissues were compared between MG group and CG group.RESULTS: The myocardial ischemia-reperfusion injury resulted in acute lung injury in the rabbits of MG group, and the duration and amplitude of the phrenic nerve discharge curve were reduced. The ultrastructure and histological analysis of the lung tissues in MG group showed acute injury. These situations were not appeared in CG group. The correlation between myocardial ischemia-reperfusion injury and acute lung injury were significant in MG group. CONCLUSION: The animal model of acute lung injury induced by left ventricular ischemia-reperfusion is reliable and feasible.     

Antioxidant effect of carnosine on H9N2 swine influenza virus-induced acute lung injury in mice

AIM:To investigate the antioxidant effect of carnosine on H9N2 swine influenza virus (H9N2-SIV)-induced acute lung injury (ALI). METHODS:One hundred and fifty SPF female BALB/c mice (6 to 8 weeks old) were randomly divided into control group, ALI group and carnosine intervention group with 50 each. The mice in control group were inoculated intranasally with normal allantoic fluid of chick embryos. The mice in ALI group were inoculated intranasally with allantoic fluid containing H9N2-SIV. The mice in carnosine group were treated with H9N2-SIV plus carnosine. On the 2nd, 4th, 6th, 8th and 14th days after treatment, 8 mice in each group were killed to observe the pathological changes of the lung. Meanwhile, the activity of superoxide dismutase (SOD) and myeloperoxidase (MPO), the content of malondialdehyde (MDA) and the wet weight/dry weight ratio (W/D) of the lung tissues were determined. RESULTS:Carnosine alleviated the symptom of the mice induced by H9N2-SIV infection, and increased the viability of the mice. In carnosine intervention group, edema degree of the lung (W/D) was apparently reduced (P<0.05). The pathological changes were alleviated on the 6th and 8th days of the experiment. On the same days, the content of MDA was lower obviously (P<0.05) and the activity of SOD was improved remarkably (P<0.05). On the 4th day of the experiment, the activity of MPO was reduced apparently (P<0.05) and continuously decreased on the 6th and 8th days (P<0.05). CONCLUSION: Carnosine protects the mice from acute lung injury induced by H9N2-SIV infection and increases the viability by reducing the content of MDA, lowering the activity of MPO, increasing the activity of SOD and inhibiting the production of free radicals and lipid peroxidation.     

Effect of hydrogen sulfide on myocardial fibrosis and PPARγ and NF-κB expression in rat model of diabetes

AIM: To explore the effects of hydrogen sulfide (H₂S) on the myocardial fibrosis in a rat model of diabetes and its mechanism.METHODS: Single intraperitoneal injection of streptozotocin (STZ) was utilized to establish a rat model of diabetes. Sodium hydrosulfide was used as an exogenous donor of hydrogen sulfide. Male SD rats were randomly divided into control group, STZ group, STZ+H₂S group and H₂S group. Eight weeks later, HE and VG staining methods were used to observe the collagen distribution and collagen volume fraction was measured by image analysis. The expression levels of type I collagen, PPARγ and NF-κB in the cardiac tissues were determined by Western blotting.RESULTS: Compared with control group, collagen distribution and the expression levels of type I collagen and NF-κB in the cardiac tissues were markedly increased (P<0.05), while PPARγ was significantly decreased in STZ group (P<0.05), but these indexes were reversed significantly in STZ+H₂S group (P<0.05). The expression levels of type I collagen, PPARγ and NF-κB had no significant difference between H₂S group and control group.CONCLUSION: Hydrogen sulfide attenuates cardiac fibrosis in diabetic rats, and its mechanism may be related to PPARγ-NF-κB signaling pathway.     

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.     

Role of heme oxygenase in cholecystokinin octopeptide ameliorating acute lung injury induced by lipopolysaccharide

AIM: To study the role of heme oxygenase (HO)-1 in the mechanism of cholecystokinin-octapeptide (CCK-8) for attenuation of acute lung injury (ALI) induced by lipopolysaccharide (LPS).METHODS: Adult male rats were randomly divided into five groups: control group,LPS group,CCK-8+LPS group,LPS+ Hm (hemin,HO-1 donor) group and LPS+ZnPP (zinc protoporphyrin,specific inhibitor of HO-1) group.PMN number in bronchoalveolar lavage fluid (BALF),the structure of the lung,MDA content,HO-1 activity,the expressions of HO-1 mRNA and protein in the lung were detected respectively.RESULTS: The lung injury in LPS group was observed,at the same time the numbers of PMN,the content of MDA,the activity and the expression of HO-1 were all higher than those in control group (all P<0.05).The degree of lung injury,PMN numbers and MDA content were lower,while the activity and the expression of HO-1 in CCK-8+LPS and LPS+Hm group were higher than those in LPS group (all P<0.05).However,the degree of lung injury,PMN numbers and MDA content were higher,the activity and the expression of HO-1 were lower in LPS+ZnPP than those in LPS group respectively (all P<0.05).CONCLUSION: CCK-8 attenuates the LPS-induced ALI by means of anti-oxidation and inhibits PMN aggregation,which are both mediated by HO-1 partly.     

Role of hydrogen sulfide in acute lung injury induced by ischemia-reperfusion of hind limbs in rats

AIM: To explore the role of endogenous and exogenous hydrogen sulfide (H₂S) in acute lung injury (ALI) induced by ischmia-reperfusion (IR) of hind limbs in rats.METHODS: A Sprague-Dawley rat model of acute lung injury was induced by ischemia of the hind limbs for 4 h and reperfusion for another 4 h. The rats (n=120) were randomly divided into 4 groups: control, IR, NaHS (H₂S donor)+IR, and propargylglycine +IR. The animals were sacrificed after reperfusion. Lung weight/body weight ratio (LW/BW) was measured and calculated. Morphological changes of the lung tissues were observed. The concentrations of H₂S, nitric oxide (NO) and carbon monoxide (CO) in plasma were tested. The content of malondialdehyde (MDA), the activity of CSE, inducible nitric oxide synthase (iNOS) and hemeoxygenase (HO) in the lungs were determined. The polymorpho-nuclear neutrophils(PMN) and protein content in bronchoalveolar lavage fluid(BALF) were also measured. The correlation of H₂S content with the above indices was analyzed.RESULTS: Compared with control group, severe injuries of the lung tissues, raised LW/BW, MDA concentration, PMN and protein contents in BALF were observed in IR group. Limb IR also made a drop in the concentration of plasma H₂S and the activity of lung CSE, while the activity of iNOS and HO in the lung tissues and the levels of plasma NO and CO increased. Administration of NaHS before IR attenuated the changes induced by IR, while pre-administration of PPG exacerbated the IR injuries and increased the plasma NO level and lung iNOS activity. The H₂S content was positively correlated with CSE activity, CO content and HO-1 activity (P<0.01), and negatively correlated with the other indices (P<0.01).CONCLUSION: Down-regulation of H₂S/CSE is involved in the pathogenesis of acute lung injury induced by IR. Endogenous and exogenous H₂S protects against lung injuries. The anti-injury effects of H₂S are related with its anti-oxidative activity to attenuate the inflammatory over-reactions in the lung induced by PMN. Down-regulation of NO/iNOS system and up-regulation of CO/HO-1 system by H₂S are also involved in the process of anti-injury to ALI.     

Effect of simvastatin on expression of Toll-like receptor 2 in mouse cytomegalovirus pneumonia

AIM: To investigate the effects of simvastatin on the expression of Toll-like receptor 2 (TLR-2), interferon-γ (IFN-γ) and monocyte chemoattractant protein-1 (MCP-1) in lung tissues of mice with mouse cytomegalovirus (MCMV) pneumonia and to explore the possible mechanism. METHODS: Male BALB/c mice (6~8 weeks old, n=40) were randomly divided into 5 groups: normal control (NC) group, MCMV infection group, simvastatin group 1 (SMV1 group), simvastatin group 2 (SMV2 group), and simvastatin group 3 (SMV3 group). The mice in SMV1, SMV2 and SMV3 groups were gavaged with simvastatin (50 mg·kg^-1·d^-1 for 7 d) 7 d before, on the same day of and 3 d after intraperitoneal injection of MCMV, while the mice in normal control group and MCMV infection group were gavaged with the same volume of normal saline. HE staining was used to observe the pathological changes of lung tissues in mice. Total tissue protein was extracted from the lung homogenates to detect the expression of TLR-2 by Western blot and immunohistochemical staining. Real-time PCR was used to analyse the content of MCMV DNA. The levels of IFN-γ and MCP-1 were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Compared with NC group, the pathological changes of the lung tissues of the mice in MCMV group showed alveolar interstitial edema, alveolar wall widening and a large number of inflammatory cells. The expression of TLR-2 in the lung tissues of the mice in model group was increased significantly. The content of MCMV DNA was increased, and the expression of IFN-γ and MCP-1 was also increased significantly. Compared with the mice in MCMV group, the pathological changes of the lung tissues of simvastatin groups showed that the inflammatory cells were decreased. The expression of TLR-2 was down-regulated. The content of MCMV DNA was decreased, and the levels of IFN-γ and MCP-1 were also decreased significantly. At the same time, the expression of TLR-2 and the content of MCMV DNA in SMV1 group were less than those in SMV2 and SMV3 groups (P<0.05), and no statistically significant difference between SMV2 and SMV3 groups was observed. CONCLUSION: Simvastatin down-regulates the TLR-2 signaling pathway, and reduces the expression of TLR-2 and replication of MCMV DNA, thus attenuating the pathological damage of the lung tissue. Early intervention with simvastatin plays an important role in preventing the infection of MCMV and reducing the inflammation.     

Effects of neutrophil extracellular traps on acute lung injury in neonatal rats

AIMTo investigate the role of neutrophil extracellular traps (NETs) in neonatal rats with acute lung injury (ALI). METHODSThirty 7-day-old SD rats were randomly divided into normal saline control group, ALI group and ALI+deoxyribonuclease (Dnase) group (each n=10). The rats in ALI group were intraperitoneally injected with lipopolysaccharides (LPS) at 20 mg/kg, and the rats in ALI+Dnase group were intraperitoneally injected with Dnase at 5 mg/kg after LPS injection. After 6 h, the rats were anesthetized with chloral hydrate, bronchial alveolar lavage fluid (BALF) was collected, and the content of cell-free DNA (cf-DNA) in BALF was detected by fluorescence microarray. The right lung tissues were fixed in 4% paraformaldehyde, and the morphological structure of the lung tissues were observed by HE staining. The content of interleukin-6 (IL-6) and tumor necrosis factor-α （TNF-α） in the left lung homogenate was measured by ELISA. Immunofluorescence and Western blot were used to detect the production of citrullinated histone H3 (CitH3) and myeloperoxidase (MPO) in the rat lung tissues. RESULTSCompared with control group, the levels of cf-DNA, CitH3, MPO, IL-6 and TNF-α in lung tissues of neonatal rats in ALI group and ALI+Dnase group were all increased (P<0.05), and severe inflammatory infiltration in the lung tissues was observed. Compared with ALI group, the levels of cf-DNA, CitH3, MPO, IL-6 and TNF-α in ALI+Dnase group were decreased (P<0.05), and the inflammatory infiltration was attenuated. CONCLUSION In neonatal rats with ALI, the level of NETs is an important indicator of lung tissue injury, and NETs may be a new target for the treatment of neonatal ALI.