α-酮戊二酸对脂多糖应激断奶仔猪生长抑制的缓解作用

试验用大肠杆菌脂多糖(LPS)多次刺激断奶仔猪建立应激模型,研究α-酮戊二酸(AKG)对断奶仔猪的生长性能和血浆激素水平的影响,探讨AKG能否缓解仔猪应激反应.选用24头健康断奶仔猪(杜洛克×长白×大白,体重(7.25±0.23)kg),随机分成3个组(空白对照组、应激对照组和AKG组),每组8个重复,每个重复1头猪.2个对照组饲喂基础日粮+1%淀粉,AKG组饲喂基础日粮+1%AKG,在试验第10天、第12天、第14天和第16天分别在应激对照组和AKG组仔猪的腹膜注射80 μg/kg LPS.试验结果显示:(1)试验第1～9天,未注射LPS时,AKG组平均日增重分别比空白对照组和应激对照组提高30.0%(P<0.05)和31.1%(P<0.05),料重比降低12.4%(P<0.05)和12.8%(P<0.05);试验第10～16天(注射LPS),应激对照组与空白对照组相比平均日增重降低28.8%(P<0.05),料重比升高16.8%(P<0.05),但AKG组的平均日增重和料重比与空白对照组相比无显著性差异(P>0.05);(2)与空白对照组相比,试验第10天,首次LPS刺激后,应激对照组的血浆胰岛素样生长因子(IGF-I)水平降低22.7%(P<0.05),而AKG组无显著变化(P>0.05);试验第16天,多次LPS刺激后,与空白对照组比较,应激对照组的IGF-I和胰岛素(INS)水平分别降低21.2%(P<0.05)和25.7%(P<0.05),而AKG组无显著变化(P>0.05).结果表明,日粮中添加1%AKG能显著缓解LPS应激对杜×长×大断奶仔猪生长的负影响.     

The role of alveolar macrophages in the pathogenesis of recurrent airway obstruction in horses

When challenged with allergens and pro-inflammatory agents, such as Aspergillus fumigatus (AF), hay dust solution (HDS) and lipopolysaccharide (LPS), the innate immune response will not only activate the immune system but also increase the amount of pro-inflammatory cytokines in the bronchoalveolar space. The aim of this study was to assess the response of equine alveolar macrophages to different aerosolized challenges and to investigate the differences in this response between horses susceptible or nonsusceptible to recurrent airway obstruction (RAO). Seven susceptible and 5 nonsusceptible horses were challenged with saline, LPS, HDS, or AF, and bronchoalveolar lavage (BAL) cytology, total cell counts, and lung function were assessed. In addition, alveolar macrophages were isolated 6 and 24 hours after challenge, and macrophage mRNA expression of tumor necrosis factor (TNF)-alpha and interleukins (IL) IL-1beta, IL-6, IL-8, and IL-10 were measured by means of real-time (RT) polymerase chain reaction (PCR). There was a significant difference in lung function, neutrophil ratios, and total cell counts in the bronchoalveolar lavage fluid between RAO-susceptible and nonsusceptible horses. In addition, the expression of TNF-alpha, IL-1beta, and IL-8 by alveolar macrophages after challenges were higher in susceptible horses, than in nonsusceptible horses. In contrast, I1-6, considered an anti-inflammatory cytokine, showed a higher expression in nonsusceptible horses 6 hours after inhalation challenge with allergens and pro-inflammatory antigens. These data suggest that the differences between susceptible and nonsusceptible horses to RAO are not only dependent on adaptive immunity but also start with an innate immune response.     

Effect of Kupffer cell blockade on activation of mitogen-activated protein kinases in response to lipopolysaccharide

AIM: Using the mouse model of lipopolysaccharide(LPS) attack,we study the effect of Kupffer cell (KC) blockade on the activation of mitogen-activated protein kinases(MAPKs) signal transduction pathway induced by LPS.METHODS: GdCl₃ (10 mg/kg) or the same volume of NS was continually injected intravenously at 48 h and 24 h before LPS (5 mg/kg) was injected into the male mice of Kunming species.The liver was then took out and KCs were isolated 30 minute after LPS was injected.The KCs isolated from the mice were cultured,and pretreated with GdCl₃ (100 μmol/L) for 1 h.The culture medium containing LPS (100 μg/L) was added and continuously incubated for 30 minute.The protein expression and phosphorylation level of ERK1/2 and p38MAPK in liver or KCs were assayed in vivo and in vitro,and effect of GdCl₃ on the phagocytosis function was observed,respectively.RESULTS: LPS induced the protein phosphorylation of ERK1/2 and p38MAPK in KCs or liver,no effect on the protein expression was observed.GdCl₃ treatment inhibited LPS-induced KCs activation and secretion of TNF-α,however,it had no effect on ERK1/2 and p38MAPK in KCs or liver,neither at the protein expression nor the phosphorylation.KCs secreted a few TNF-α with short time treatment with GdCl₃ alone in vitro.CONCLUSION: KC blockade with GdCl₃ alleviates LPS-induced KCs activation and the release of TNF-α not through modulating intracellular ERK1/2 or p38MAPK signal transduction pathways.We presume that GdCl₃ might reduce liver injury through cross talk of other intracellular signal transduction pathways (JNK,NF-кB,GPCR,etc).     

Effect of exogenous hydrogen sulfide on expression of NLRP3 inflammasome in hepatocytes

AIM: To evaluate the effect of exogenous hydrogen sulfide (H₂S) on the expression of NLRP3 inflammasome in hepatocytes.METHODS: The hepatocytes L02 and SMMC-7721 were used to establish the model of inflammation by stimulating with lipopolysaccharide (LPS) at different concentrations in vitro. The expression of NLRP3 inflammasome in the hepatocytes was detected by Western blot and the cell viability was measured by MTT assay for determining appropriate concentration of LPS. The hepatocytes were divided into 4 groups:the cells in control group were incubated with normal medium for 18.5 h; the cells in LPS group were incubated with normal medium for 0.5 h followed by 100 μg/L LPS for 18 h; the cells in LPS+H₂S group and H₂S group were incubated with 200 μmol/L sodium hydrosulfide hydrate (NaHS) for 0.5 h followed by 100 μg/L LPS or normal medium for 18 h, respectively. The protein expression of NLRP3 and caspase-1 in the cells of every group was determined by Western blot. RESULTS: Compared with control group, the protein expression of NLRP3 and caspase-1 increased significantly in LPS group (P<0.05) and had no significant change in H₂S group. Compared with LPS group, the protein expression of NLRP3 and caspase-1 in LPS+H₂S group decreased significantly (P<0.05). CONCLUSION: In hepatocytes, exogenous H₂S suppresses the expression of NLRP3 inflammasome.     

Binding characterization of cholecystokinin receptors in rat pulmonary interstitial macrophages

AIM: To investigate the binding characteristics of cholecystokinin receptors in rat pulmonary interstitial macrophages (PIMs). METHODS: The PIMs were isolated from rat lung tissues, purified using the collagenase digestion method combined with alveolar lavage and pulmonary vessel perfusion. The PIM membrane was obtained by supercentrifuge. Receptors for CCK in PIMs were examined using labeled CCK-8S as ligand. The specificity of -CCK-8S binding to PIMs membrane and the subtypes of CCK receptors were determined by competitive inhibition experiments with CCK-8S, CCK-A and CCK-B receptors selective antagonists (CR1409 and CR2945). The effects of time and incubation temperature on the specific binding were also observed. RESULTS: The specific binding of -CCK-8S was not detected in normal rat PIMs, but was detected in the rat administrated with LPS for 48 h. The capacity of ligand-receptor binding was dependent on the incubation temperature and time. Scatchard analysis of the saturation curves suggested that the presence of CCK receptors with high affinity[Kd=(0.68士0.28) nmol/L] and low binding capacity [Bmax=( 32.50±12.70) pmol·g^-1in PIMs. By means of competitive inhibition studies, the specific binding of [³H]-CCK-8S to rat PIMs was inhibited by unlabelled CCK-8S[IC₅₀=(3.20士1.13)nmol/L],CCK-AR specific antagonist CR 1 409 and CCK-BR specific antagonist CR 2945[IC₅₀=(2.30士0.08)nmol/L].CONCLUSION:These results suggest the presence of two subtypes of CCK一AR and CCK-BR and provide a structural basis for CCK to play a pivotal role in PIMs.     

Losartan inhibits LPS-induced GFAP expression via AMPK activation in mouse hippocampus

AIM: To investigate the effects of losartan on lipopolysaccharide (LPS)-induced glial fibrillary acidic protein (GFAP) expression, and to determine whether adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) activation is involved in the mechanism.METHODS: Adult male KM mice were divided into control group, LPS model group, losartan treatment group, and losartan and Compound C co-treatment group. To establish a model of central nervous system inflammation, the mice received daily intracerebroventricular injection of LPS (24 μg/d) for 2 d. Daily losartan administration (0.5, 1 or 5 mg·kg^-1·d^-1, ip) initiated at 14 d prior to LPS injection. Compound C (10 mg/kg, ip), a selective AMPK inhibitor, started to be injected daily at 2 d prior to LPS injection. The hippocampal tissues in each group were isolated at 3 d after the last LPS injection, and then the protein levels of GFAP, AMPK, p-AMPK, mammalian target of rapamycin (mTOR) and p-mTOR were determined by Western blot.RESULTS: Twice LPS injections significantly increased the expression of GFAP in the hippocampus (P<0.01). Losartan inhibited LPS-induced GFAP expression in a concentration-dependent way, and losartan at 5 mg·kg^-1·d^-1 significantly inhibited GFAP expression and AMPK activation (P<0.05), but it had no obvious effect on mTOR activation. Furthermore, Compound C significantly reversed the effect of losartan treatment on LPS-induced GFAP expression and AMPK phosphorylation (P<0.05).CONCLUSION: Losartan inhibits LPS-induced GFAP expression in the mouse hippocampus, and AMPK activation but not mTOR, is involved in the mechanism.     

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.     

L-精氨酸对脂多糖刺激断奶仔猪生产性能、血液生化指标和内脏器官重量的影响

试验研究L-精氨酸(Arg)对脂多糖(LPS)刺激断奶仔猪[(21±1)d,平均体重(5.78±0.26)kg]生产性能、血液生化指标和内脏器官重量的影响。试验采用单因子设计,分为以下4个处理组:(1)基础日粮(非应激对照组);(2)基础日粮 LPS(应激对照组);(3)基础日粮 LPS 0.5%Arg(0.5%Arg组);(4)基础日粮 LPS 1.0%Arg(1.0%Arg组)。在试验第16天,给处理2、处理3和处理4组仔猪按每千克体重注射100μgLPS,处理1组注射等量的生理盐水,3h后采血。试验第18天屠宰仔猪测定内脏器官的重量。结果表明:(1)LPS刺激导致断奶仔猪日增重和日采食量显著下降(P<0.001),而0.5%Arg可缓解LPS刺激所导致的日增重下降(P<0.001);(2)LPS刺激导致断奶仔猪血浆葡萄糖、总蛋白、白蛋白和球蛋白含量显著降低(P<0.05),而0.5%或1.0%Arg可在一定程度上缓解LPS刺激导致的血浆总蛋白、白蛋白和球蛋白含量降低;(3)LPS刺激导致胃绝对重量显著降低(P<0.05)和肝脏相对重量增加(P<0.05),0.5%或1.0%Arg可在一定程度上缓解LPS刺激导致的胃绝对重量的减轻和肝脏相对重量的增加。这表明Arg在一定程度上缓解了LPS刺激所导致生长抑制和应激反应。     

Identification of a highly virulent strain of <Emphasis Type="Italic">Xanthomonas axonopodis</Emphasis> pv. <Emphasis Type="Italic">malvacearum</Emphasis>

A highly virulent strain (HVS) of Xanthomonas axonopodis pv. malvacearum (Xam) was first reported in Africa in 1983, infecting all commercial cultivars of cotton including the immune cv. ‘101–102B’. The HVS was considered to be a new race of pathovar malvacearum (race 20). Here we studied a HVS (GSPB 2388) isolated in Sudan, which causes symptoms that clearly differed from the typical angular water-soaked spots of bacterial bright of cotton. Our investigations showed that extracellular cellulase activity of this HVS was higher than that of the control strain GSPB 1386 (race 18). Additionally, SDS-PAGE indicated that the HVS cell wall contained short LPS molecules with fewer O-chain repeating units, lacking in GSPB 1386. The higher cellulase activity and the distinct lipopolysaccharide of HVS are correlated with the higher virulence and deviating symptom formation. Rep-PCR fingerprinting showed that the HVS was very closely related to other strains of Xam.