Dissertation > Excellent graduate degree dissertation topics show

Gut-lympb Hypothesis in the Pathdgenesis of Sepsis in Rats and Differential Proteomics Research in Lymph

Author: ZhangPing
Tutor: LinZhaoFen
School: Second Military Medical University
Course:
Keywords: sepsis acute lung injury lymph differential proteomics
CLC: R459.7
Type: PhD thesis
Year: 2013
Downloads: 38
Quote: 0
Read: Download Dissertation

Abstract

Background: The pathogenesis of distant organ dysfunction in patients withsepsis is not yet clear, and the exact effective therapies for sepsis are lacking. In recentyears, the gut-lymph hypothesis has been verified in shock, intestinalischemia/reperfusion injury, acute pancreatitis and other animal models. It is thoughtthat biologically toxic factors derived from the gut transported by mesenteric lymphinto the circulation during critical illness. There have been a few proteomic studiesthat investigate the differences between normal lymph and hemorrhagic shock-oracute pancreatitis-lymph. However, there is little literature about the gut-lymphhypothesis in the cecal ligation and puncture (CLP) model, which widely used instudy mimicking the clinical development of sepsis. The aims of this study were:(i)to investigate whether the mesenteric lymphatics was the predominant conduit oflung-toxic factors in CLP rats and whether it played a major role in the pathogenesisof MODS;(ii) to use isobaric tag technology (iTRAQ) for relative protein quantitationtogether with capillary high performance liquid chromatography (HPLC) to providethe profile of proteins in CLP-lymph;(iii) to apply a bioinformaticsinteraction-proteome approach to determine probable functional and biologicalrelevance of proteins that guarantee further investigation in relation to the earlybiomarkers and therapeutic targets of sepsis associated with CLP.Part Ⅰ Thoracic Duct Lymph Circulation in Acute Lung Injury inCecal Ligation and Punctured RatsObjective: In previous work, Koch’s postulates have been satisfied in gut-lymphhypothesis in non-CLP induced sepsis models. We therefore hypothesized thatlymphatic duct ligation prevents acute lung injury in CLP rats and injection ofthoracic duct lymph from CLP rats provokes acute lung injury in a naive animal.Methods:1. Upon administration of anesthesia, male SD rats were subjected to cecal ligation and puncture (CLP); groups of rats were subjected to CLP with orwithout thoracic duct ligation (TDL) immediately before the CLP procedure. Thesurvival rate and the content of myeloperoxidase (MPO) in lung, liver and kidneyhomogenate were detected.2. One set of SD rats (lymph recipients) was anesthetized,with the right femoral vein cannulated. Thoracic lymph from the CLP donor rat wasdelivered to the recipient.3. At3,6,18, or24hours after sham or CLP, the thoraciclymph was collected for one hour to assay the concentration of IL-6and IL-10.Results:1. The survival rate of TDL+CLP rats was significantly higher than thatof CLP rats (90%versus.40%, p=0.029). The lung injury of TDL+CLP rats was lessthan that of CLP rats pathologically. Higher concentration of pulmonary MPO wasdetected in both groups (TDL+CLP, CLP).2. Neutrophil accumulation in the lungswas elevated in the CLP-6h lymph transfusion group compared to three other groups(sham-6h, CLP-24h, and sham-24h lymph transfusion groups) and instrumentedcontrol (MPO:81.96±30.63versus34.84±13.91ng/mg lung protein in CLP-6hversus CLP-24h lymph transfusion, n=6in each group, p＜0.05).3. The levels of IL-6and IL-10in lymph were higher than those in serum, and those in the CLP group wereelevated compared to sham group. The levels of IL-6and IL-10in CLP lymph weresignificantly lower at18h and24h after operation while still higher than those inserum at the same time point.Conclusion: There were acute lung injury-inducing factors in thoracic lymphfrom CLP rats. Pro-inflammatory cytokines in serum may derive from intestinallymph in CLP animals. The gut-lymph system may play a leading role in thepathogenesis of distant organ failure in CLP-induced sepsis rats.Part Ⅱ Proteomics and Bioinformatics Analysis of ThoracicLymph in CLP RatsObjective: The aim of this study was to provide the comprehensive descriptionof the proteome of CLP-conditioned thoracic lymph in rats.Methods: The thoracic lymph was subjected to proteomic analysis using iTRAQand capillary high performance liquid chromatography (HPLC) and then severalproteins were highlighted for possible further research using a bioinformaticsapproach.Results: One hundred and fifty eight of the984proteins had a significant increase in their relative abundance in the CLP-conditioned lymph. A bioinformaticsapproach highlighted five signaling pathways, three metabolic pathways and onedisease pathway as changing most significantly in CLP. Using a network ofprotein-protein interactions, we identified several proteins: amyloidogenicglycoprotein, apolipoprotein E, Annexin A1, Neutrophil gelatinase-associatedlipocalin, S100A8and S100A9.Conclusion: This study provided the detailed description of protein changes inCLP-conditioned thoracic lymph, and several targets for possible further researchwere identified using a bioinformatics approach.

Gut-lympb Hypothesis in the Pathdgenesis of Sepsis in Rats and Differential Proteomics Research in Lymph

Abstract

Related Dissertations