草鱼对鱼害粘球菌类脂多糖的免疫反应

LPS 浓度为2mg/ml 的免疫鱼死亡率最低,为5%;1mg/1ml的免疫鱼,死亡率为18%;3mg/ml 的免疫鱼死亡率为26%;而4mg/ml 的免疫鱼死亡率最高,达50%.

细菌类脂多糖(Lps)对桑蚕血球细胞培养系的蛋白激酶C和A活性的诱导

使用含桑蚕血球细胞(主要是颗粒细胞和浆细胞)的离体培养系,经各种刺激物诱导后,对蛋白激酶C(下称PKC)和蛋白激酶A(PKA,需cAMP型)的活性进行了试验。血球细胞经大肠杆菌中的类脂多糖(lipopolysaccharide,LPS)、离子霉素、霍乱弧菌产生的霍乱毒素或笨基乙酸汞(杀菌剂)(4β—phorbor 12—myristate 13 acetate)(PMA)处理后便可清楚地检测到PKC的活性,而没有上述刺激物诱导时,其活性情况没试验过。结果表明,不仅LPS而且Ca^(2+)和一种G蛋白均可能参与了PKC活性诱导的信号转导。同样用LPS、dcAMP、离子霉素或霍乱毒素处理血球细胞,对PKA的活性进行了类似的检测,而不经处理的对照细胞没有PKA活性,而且LPS、cAMP、Ca^(2+)和G蛋白很可能也参与了PKA活性诱导过程中的信号转导。用抗兔脑PKC—α的单克隆抗体进行蛋白质印迹分析,结果以LPS处理的血球细胞样品中有一种与单抗有交叉反应的90KDa蛋白质,而未经LPS处理的对照样品不存在这种蛋白。桑蚕血球细胞内的PKC和PKA被细菌感染后的LPS激活后,可以诱导自身防御反应,例如抗菌蛋白基因的表达。

Neural pathway for fever generation

Fever is an adaptive host response coordinated by the central nervous system （CNS） during systemic immune challenge. Recent research shed light on the mechanism of fever generation, particularly the underlying neural pathways. In this review, we first briefly summarize current views on the mechanism of sensing microbial infection by the nervous system, and the roles of prostaglandin E2 （PGE2） and its receptors in fever; then we focus on the neural circuits underlying fever generation, particularly their relationship with the distribution of PGE2 receptors within the CNS. At the end, an overall neurochemical model of fever generation is presented, pointing to the direction for future studies.

Magnolol attenuates sepsis-induced gastrointestinal dysmotility in rats by modulating inflammatory mediators

AIM： To investigate the protective effects of magnolol on sepsis-induced inflammation and intestinal dysmotility. METHODS： Sepsis was induced by a single intraperitoneal injection of lipopolysaccharide （LPS）. Male Wistar rats were randomly assigned to one of three treatment groups： magnolol prior to LPS injection （LPS/Mag group）; vehicle prior to LPS injection （LPS/Veh group）; vehicle prior to injection of saline （Control/Veh）. Intestinal transit and circular muscle mechanical activity were assessed 12 h after LPS injection. Tumor necrosis factor-α （TNF-α）, interleukin-10 （IL-10）, monocyte chemoattractant protein-1 （MCP-1） and inducible nitric oxide synthase （iNOS） mRNA in rat ileum were studied by RT-PCR 2 h after LPS injection. Nuclear factor-κB （NF-κB） activity in the intestine was also investigated at this time using electrophoretic mobility shift assay. In addition, antioxidant activity was determined by measuring malondialdehyde （MDA） concentration and superoxide dismutase （SOD） activity in the intestine 2 h after LPS iniection.RESULTS： Magnolol significantly increased intestinal transit and circular muscle mechanical activity in LPS- treated animals. TNF-α, MCP-1 and iNOS mRNA expression in the small intestine were significantly reduced after magnolol treatment in LPS-induced septic animals, compared with untreated septic animals. Additionally,magnolol significantly increased IL-10 mRNA expression in septic rat ileum. Magnolol also significantly suppressed NF-κB activity in septic rat intestine. In addition, magnolol significantly decreased MDA concentration and increased SOD activity in rat ileum. CONCLUSION： Magnolol prevents sepsis-induced suppression of intestinal motility in rats. The potential mechanism of this benefit of magnolol appears to be modulation of self-amplified inflammatory events and block of oxidative stress in the intestine.

Protective Effect of Rhubarb on Endotoxin-Induced Acute Lung Injury

To approach the mechanism of lipopolysaccharide (LPS) in causing acute lung injury (ALI) and the protective effect of rhubarb and dexamethasone, lung specimens were examined with macroscopy, microscopy, electron microscopy and the biological markers of ALI including lung wet/dry weight, the rate of neutrophils and protein content in the pulmonary alveolar lavage fluid, pulmonary capillary permeability and pulmonary alveolar permeability index were observed. The mechanism of the ALI is mainly due to direct injury of alveolar epithelium and pulmonary vascular endothelium. Rhubarb and dexamethasone could significantly reduce the edema of the lung tissue, decrease the red blood cell exudation, neutrophil infiltration and plasma protein exudation in the alveoli and all the biological markers in comparison with the ALI model rats, indicating they have protective action on vascular endothelium and alveolar epithelium.

Actions of NO and INOS on Endotoxin Induced rat Acute Lung Injury and Effect of Rhubarb on Them

This study is to explore the actions of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) on endotoxin (lipopolysaccharide, LPS) induced rat acute lung injury (ALI) and effect of Rhubarb on them. LPS was injected into the sublingual vein of male Wistar rats to prepare ALI animal models. The rats were divided into 4 groups: LPS, control, Rhubarb, and dexamethasone. Macroscopic and histopathological examinations of the lung specimens were performed and the biological indexes of lung, including wet weight/dry weight, the rate of neutrophils and protein content in the pulmonary alveolar lavage fluid, pulmonary vascular permeability and pulmonary alveolar permeability were observed. In the mean time, the contents of serum NO and the activities of lung tissue homogenate iNOS were measured. The results showed that in the LPS group, the injury and celluar infiltration in the pulmonary stroma and alveoli were more prominent than that in the control group. Lung wet weight/dry weight, the rate of neutrophils, protein content, pulmonary alveolar permeability, pulmonary vascular permeability were significantly increased (P<0.01); NO and iNOS were also markedly elevated (P<0.01). In the groups of dexamethasone and Rhubarb, the histopathological changes were significantly milder, and all the above biological indexes of lung injury and the contents of NO and the activities of iNOS were correspondingly decreased (P<0.05). The above data demonstrate that NO and the activities of iNOS play an important role in the onset of ALI; dexamethasone and Rhubarb interfering treatment can ameliorate lung injury and decrease the concentrations of NO and iNOS, showing that through inhibiting the levels of NO and the activities of iNOS, these 2 agents exert protective effect on ALI induced LPS.

Cholecystokinin octapeptide inhibits the in vitro expression of CD14 in rat pulmonary interstitial macrophages induced by lipopolysaccharide

OBJECTIVE: To study the effect of cholecystokinin octapeptide (CCK-8) on lipopolysaccharide (LPS)-stimulated pulmonary interstitial macrophages (PIM) in vitro. METHODS: PIM were isolated and cultured in the presence or absence of LPS, CCK-8, proglumide (the antagonist of CCK receptors) and vehicle. The expression of membrane CD14 (mCD14) protein was assayed by flow cytometry and soluble CD14 (sCD14) in the supernatant was analyzed semi-quantitatively by Western blot. TNF-alpha in the supernatant was detected with ELISA. RESULTS: CCK-8, at concentrations of 10(-7) mol/L and 10(-6) mol/L, significantly inhibited the expression of mCD14. Release of sCD14 and TNF-alpha in the supernatant was up-regulated by LPS (1 microg/ml) but reduced by CCK-8. The effect of CCK-8 was inhibited by proglumide. CONCLUSION: CCK-8 negatively modulated several functions of LPS-stimulated PIM through CCK receptors. This may be one of the mechanisms for CCK-8 to alleviate inflammation in lung tissue during endotoxemia.

Study on the antipyretic effect of pushing Tianheshui in young rabbits: focus on the α-MSH-mediated cAMP/PKA/NF-κB signaling pathway

Objective:To explore the antipyretic effect and partial mechanism of the pushing Tianheshui manipulation on lipopolysaccharide(LPS)-induced fever in young New Zealand rabbits.Methods:Thirty 50-day-old New Zealand rabbits were randomly assigned to five groups,including a normal group,a model group,a Tuina(Chinese therapeutic massage)group,a Tuina control group,and a drug group,with 6 rabbits in each group.All groups except for the normal group received LPS injections through the marginal ear vein to induce fever.One hour post-modeling,the Tuina and Tuina control groups received pushing Tianheshui manipulation and pushing manipulation on the medial middle of the hind limbs,respectively,administered every hour for a total of 3 interventions.The drug group was given acetaminophen oral liquid via gavage.Anal temperature was recorded every 30 min for 4.0 h to monitor temperature changes among groups.At 4.0 h post-modeling,hypothalamus samples from each group were analyzed using Western blotting(WB)and real-time quantitative polymerase chain reaction(RT-qPCR)to measure the relative expression levels ofα-melanocyte-stimulating hormone(α-MSH),melanocortin 4 receptor(MC4R),cyclic adenosine monophosphate(cAMP),protein kinase A(PKA),nuclear factor-κB p65(NF-κB p65),and interleukin(IL)-1βproteins and their mRNAs.Results:Compared to the model group,the Tuina group showed a significant reduction in the anal temperature from 3.5 h to 4.0 h post-modeling(P<0.05).The Tuina control group did not show a significant temperature reduction from 0.5 h to 4.0 h post-modeling(P>0.05).The drug group exhibited a significant temperature reduction from 1.5 h to 4.0 h post-modeling(P<0.05).At 4.0 h post-modeling,compared to the model group,the Tuina group showed significantly increased relative expression ofα-MSH and MC4R proteins and mRNAs(P<0.05)and significantly decreased relative expression of cAMP,PKA,NF-κB p65,and IL-1βproteins and mRNAs in the hypothalamus tissue(P<0.05).No significant differences were observed in these parameters in the Tuina control group compared to the model group(P>0.05).Conclusion:Pushing Tianheshui manipulation demonstrated a significant antipyretic effect,potentially linked to point specificity.Its mechanism may involve theα-MSH-mediated cAMP/PKA/NF-κB pathway.