Anti—inflammatory effect of cholecystokinin and its signal transduction mechanism in endotoxic shock rat

AIM：To study the anti-inflammatory effects of choecystokinin-octapeptide(CCK-8)on lipopolysaccharide(LPS)-induced endotoxic shock(ES)and further investigate its signal transduction pathways involving p38mitogen-activated protein kinase(MAPK)andIкα.METHODS:Eighty-four rats were divided randomly into four groups:LPS(8ng·kg^-1,iv)inducedES;CCK-8(40μg·kg^-1,iv)pretreatment10min before LPS(8mg·kg^-1);CCK-8(40μg·kg^-1,iv)ornormal saline (control)groups.The inflammatory changes of lung and spleen,phagocytic function of alveolar macrophage,quantification of inflammatory cells in bronchoalveolar lavage(BAL)were investigated in rats by using hematoxylin and eosin(HE)staining.phagocytosis of Candida albicans and differential cell counting,Nitric oxide(NO)production in serum,lung and spleen was measured with the griess reaction.The mechanism involving p38mapkandIкB-αsignal pathways was investigated by Western blot.RESULTS:Inflammatory changes of lung and spleen induced by LPS were alleviated by CCk-8,the increase of NOinduced by LPSin serum,lung and spleen was significantly inhibited and the neutrophil infiltration in BALwas significantly reduced by CCK-8,The number of neutrophils was(52±10)×10^6cells·L^-1inCCK-8+LPS(P<0.01).The phagocytic rate of CCK-8 group increased to (62.49±9.94)%,compared with control group(48.16±14.20)%,P<0.05,The phagocytosis rate was(85.14±4.64)%in LPSgroup,which reduced to(59.33±3.14)%inCCK-8|LPSgroup(P<0.01).The results of phagocytosis indexes showed similar changes.CCK-8may play an important role in increasing the expression of p38MAPKand decreasing the degradation of IкB-αin lung and spleen of ES rats. effects,which may be related to activation of p38MAPKand inhibition on the degradation of IкB-α.     

The role of endotoxin,TNF—α,and IL—6 in inducing the state of growth hormone insensitivity

AIM：Critical illnesses such as sepsis,trauma,and burns cause a growth hormone insensitivity,wehich leads to an increased negative nitrogen balance.Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-α,IL-6,and IL-1 which may play a very important role in inducing the growth hormone insensitivity,The objective of this current study was to investigate the role of endotoxin,TNFα and IL-6 in inducing the growth hormone insensityvity at the receptor and post-receptor levels.METHODS:Spageu-Dawley rats were injected with endotoxin,TNF-α,and IL-6,respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously,All rats were killed at different time points,The expression of IGF-I,GHR,SOCS-3 and β-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay,the levels of TNF-α and IL-6 were detected by ELISA.RESULTS:There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection,However,liver IGF-1 mRNA expression had been obviously down-regulated in endotoxeminc rats.Liver GHR mRNA expression also had a predominant downregulation after endotoxin injection,The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection,being decreased by 53% compared with control rats.For GHR mRNA expression,the lowest expression occurred at 8h and had a 81% decrease.Although SOCS-3 mRNA was weakly expressed in control rats,it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats.Exogenous GH could enhance IGF-1 mRNA expression in control rats,but if did fail to prevent the decline in IGF-1 mRNA expression in endotoxemic rats,Endotoxin stimulated the production of TNF-α and IL-6,and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression.The liver GHR mRNA expression was obviously down-regulated after TNF-α iv injection and had a 40 decresase at 8 h,but the liver socs-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.CONCLUSION:The growth homone insenstivity could be induced by LPS injection,which was associated with down regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level The in vivo biological activities of LPS were mediated by TNF-α and IL-6 indirectly,and TNF-αand IL-6 may exert their effects on.the receptor and post-receptor levels respectively.     

CCK-8 inhibits expression of TNF-α in the spleen of endotoxic shock rats and sigual transduction mechanism of p38 MAPK

AIM: To study the effect of sulfated cholecystokinin-octapeptide (CCK-8) on systemic hypotension, gene andprotein expression of TNF-α in spleen of lipopolysaccharide(LPS)-induced endotoxic shock (ES) rats, and furtherinvestigate the signal transduction mechanism of p38mitogen-activated protein kinase (MAPK).METHODS: The changes of blood pressure were observedusing physiological record instrument in four groups of rats:LPS(8 mg@kg-1, iv), CCK-8 (40μg@kg-1, iv)pretreatment10min before LPS (8 rmg@kg-1), CCK-8 (40μg@kg-1, iv) ornormal saline (control) group. The content of TNF-αinspleen was assayed 2 h after LPS administration usingELISA kit and the expression of TNF-α mRNA was examined30 min, 2 h and 6 h after LPS administration by reversetranscribed polymerasa chain reaction (RT-PCR). Activationof p38 MAPK was detected with Western blot 30 min afterLPS administration.RESULTS: CCK-8 reversed LPS-induced decrease of meanarterial pressure (MAP) in rets. The content of TNF-α inspleen was (282 ± 30) ng@ L-1 in control group, while itincreased to (941 ± 149) ng@L-1 in LPS group, P＜ 0.01.CCK-8 significantly inhibited the LPS-induced increase ofTNF-α content in spleen. lt decreased to (462 ± 87) ng@ L- 1 inCCK- 8 + LPS group, P ＜ 0.01. The expression of TNF-αmRNA 30 min and 2 h after treatment was stronger in LPSgroup, while it was lowered after CCK-8 pretreatment. Thep38 MAPK expression increased significantly in LPS group(5.84 times of control) and CCK-8 increased the activationof p38 MAPK in ES rats (10.74 times of control).CONCLUSION: CCK-8 reverses the decrease of MAP in ESrats and has inhibitory effect on the gene and proteinexpression of TNF-α in spleen, and p38 MAPK may beinvolved in its signal transduction mechanisms.     

p38 MAPK信号转导通路与脑缺血

p38丝裂原活化蛋白激酶（mitogen．activatedproteinkinase，MAPK）是一类重要的细胞内信号转导通路，其主要作用是参与炎症调节和细胞凋亡。脑缺血时，p38 MAPK被激活，其表达水平以及上游和下游蛋白磷酸化水平均发生改变。缺血预处理可能通过p38 MAPK信号转导通路介导脑缺血后神经细胞的存亡。     

p38MAPK信号转导通路与脑缺血

p38丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)是一类重要的细胞内信号转导通路,其主要作用是参与炎症调节和细胞凋亡.脑缺血时,p38 MAPK被激活,其表达水平以及上游和下游蛋白磷酸化水平均发生改变.缺血预处理可能通过p38 MAPK信号转导通路介导脑缺血后神经细胞的存亡.     

p38MAPK信号通路与内皮细胞激活

内皮细胞激活是内皮细胞损伤的始动因素,是引起各种不同程度的炎症反应和细胞凋亡的前提条件 ;丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK) 是哺乳动物细胞中重要的信号转导通路,其中 p38MAPK 通路在细胞应激、细胞生长、凋亡和炎症等多种生理和病理过程中起重要作用,越来越引起业界的广泛关注,本文就 p38MAPK 信号通路及其与内皮细胞激活的相关性做一综述,旨在进一步对内皮细胞损伤引发心血管疾病研究提供参考资料。     

p38MAPK对轻度热应激大鼠脾脏巨噬细胞免疫功能的影响

目的: 探讨p38MAPK在Bip蛋白介导的体外轻度热应激大鼠巨噬细胞功能改变中的信号作用.方法: p38MAPK抑制剂预处理大鼠脾脏巨噬细胞,将细胞置于41℃恒温箱中,使细胞轻度热应激,1 h后恢复到37℃(抑制组),以未应激(对照组)和41℃热应激1 h后60 min巨噬细胞(应激组)为对照,分别检测3组巨噬细胞吞噬、杀伤、趋化功能,同时检测p38MAPK蛋白和Bip蛋白的表达.结果: p38MAPK抑制剂预处理大鼠脾脏巨噬细胞,与应激组比较,轻度热应激后巨噬细胞吞噬、趋化和杀伤活性明显降低(0.17±0.01 vs 0.74±0.03,33.32±3.55 vs 82.07±5.17,24.20%±2.39% vs 60.80%±4.02%,均P<0.01);应激组p38MAPK蛋白表达明显上调,p38MAPK抑制剂预处理后,抑制组p38 MAPK蛋白表达受到抑制,与应激组比较差异有显著性(p38/β-actin: 2.863±0.794 vs 4.752±1.386,P<0.01);Bip蛋白的表达(Bip/β-act in)也因p38MAPK抑制剂预处理而由应激组的1.270±0.535降至抑制组的1.028±1.061( P<0.05).结论: p38MAPK抑制剂可显著抑制轻度热应激大鼠巨噬细胞吞噬、趋化和杀伤功能以及p38MAPK和Bip蛋白的表达.     

p38 MAPK信号转导通路参与NO诱导兔关节软骨细胞凋亡

目的探讨p38 MAPK信号转导通路在软骨细胞凋亡中的作用。方法体外培养兔关节软骨细胞,一氧化氮(NO)供体NOC-18和p38 MAPK抑制剂SB203580作用于细胞24 h,用AnnexinV-FITC/PI流式细胞术检测软骨细胞凋亡率,W estern b lot测定p38、磷酸化p38蛋白的表达水平。结果与对照组比较,SB203580显著降低了NOC-18诱导的软骨细胞凋亡率(P<0.05);NOC-18以浓度依赖的方式促进p38 MAPK的磷酸化,而SB203580能抑制其磷酸化(P<0.05)。结论p38 MAPK通路参与了NO诱导的兔关节软骨细胞凋亡的信号转导。     

Bile-pancreatic juice exclusion increases p38MAPK activation and TNF-alpha production in ligation-induced acute pancreatitis in rats.

Acute pancreatitis is associated with stress kinase activation and cytokine production. We hypothesize that bile-pancreatic juice exclusion activates p38(MAPK) and induces TNF-alpha production in ligation-induced acute pancreatitis. We compared rats with 1-3 h of duct ligation, duct ligation with duodenal bile-pancreatic juice replacement from a donor rat, and sham operation. Pancreatic homogenates were analyzed as follows: (a) Immunoblots using phospho-specific p38(MAPK) antibody showed increased p38(MAPK) activation after ligation that was inhibited by bile-pancreatic juice replacement. (b) Immune-complex kinase assay using ATF-2 as substrate showed increased p38(MAPK) activation after ligation that was subdued by bile-pancreatic juice replacement. (c) ELISA showed increased pancreatic TNF-alpha production after ligation that was significantly ameliorated by bile-pancreatic juice replacement. CONCLUSION: Bile-pancreatic juice exclusion from gut increases p38(MAPK) activation and TNF-alpha production in this experimental model. Our findings support our central hypothesis that bile-pancreatic juice exclusion exacerbates cell stress and acute inflammation in ligation-induced acute pancreatitis.     

Pro-apoptotic gene expression mediated by the p38 mitogen-activated protein kinase signal transduction pathway

Neurotrophic factor deprivation causes apoptosis by a mechanism that requires macromolecular synthesis. This fact suggests that gene expression is necessary to achieve cell death. To identify mRNA that is expressed in apoptotic cells we used subtractive hybridization with cDNA prepared from neuronal pheochromocytoma cells. Monoamine oxidase (MAO) expression was increased in cells during nerve growth factor withdrawal-induced apoptosis. The increased apoptosis and induction of MAO was prevented by inhibition of the p38 mitogen-activated protein (MAP) kinase pathway. MAO may contribute to the apoptotic process because inhibition of MAO activity suppressed cell death. Together, these data indicate that MAO may be a target of pro-apoptotic signal transduction by the p38 MAP kinase pathway.