發(fā)布時間：2018-06-24 03:48

  本文選題：膿毒癥 + 免疫抑制��； 參考：《華中科技大學(xué)》2015年博士論文

【摘要】：研究背景：膿毒癥是機(jī)體對嚴(yán)重感染作出的一系列復(fù)雜的免疫反應(yīng),從初期的由細(xì)胞因子介導(dǎo)的高炎癥反應(yīng)階段逐步進(jìn)展到后期的低炎癥反應(yīng)階段。膿毒癥后期機(jī)體處于免疫抑制狀態(tài),表現(xiàn)為機(jī)體清除侵襲病原體的能力下降及對條件致病菌的易感性增加,目前已成為膿毒癥患者的主要死亡原因。髓源抑制細(xì)胞(myeloid-derived suppressor cells, MDSCs)是由各類不成熟的髓系細(xì)胞構(gòu)成的異質(zhì)性細(xì)胞群體,膿毒癥后MDSCs會發(fā)生過度擴(kuò)增和活化,通過影響T細(xì)胞增值和功能,抑制適應(yīng)性免疫反應(yīng),從而誘導(dǎo)免疫抑制狀態(tài)。體外實(shí)驗、動物載體實(shí)驗及臨床藥物試驗均已證實(shí)全反式維甲酸((all-trans-retinoic acid,ATRA)能誘導(dǎo)MDSCs分化成熟為巨噬細(xì)胞、樹突狀細(xì)胞和粒細(xì)胞從而減輕MDSCs對T細(xì)胞的抑制作用。但是這些研究均集中在腫瘤領(lǐng)域,缺乏在膿毒癥中的證據(jù)。本研究擬探究膿毒癥時,特別是膿毒癥后期發(fā)生免疫抑制時,ATRA是如何調(diào)控MDSCs的擴(kuò)增和功能從而影響機(jī)體免疫狀態(tài)和預(yù)后的,以及可能參與其中的信號轉(zhuǎn)導(dǎo)通路。 方法：本研究采用小鼠盲腸結(jié)扎穿孔(cecal ligation and puncture,CLP)膿毒癥模型并在其基礎(chǔ)上通過綠膿桿菌滴鼻建立了二次感染打擊模型。觀察了ATRA處理對小鼠CLP+二次細(xì)菌打擊模型生存情況；CLP小鼠誘導(dǎo)產(chǎn)生的MDSCs的數(shù)量、表型、形態(tài)學(xué)和免疫抑制活性；CD4+T細(xì)胞增值、凋亡和遲發(fā)型超敏反應(yīng)(delayed type hypersensitivity, DTH);血清及MDSCs中炎癥因子分泌水平：及相關(guān)信號傳導(dǎo)分子表達(dá)的影響。 結(jié)果：ATRA能明顯減少CLP后期小鼠脾臟、外周血和骨髓中MDSCs的絕對數(shù)量和所占總細(xì)胞的百分比,并降低MDSCs的精氨酸酶活性和NO產(chǎn)生量,恢復(fù)其促炎／抗炎細(xì)胞因子的分泌平衡,最終減輕其對CD4+T細(xì)胞的抑制作用。這些變化帶來的是膿毒癥小鼠后期機(jī)體免疫狀態(tài)的好轉(zhuǎn),具體表現(xiàn)為CD4+T細(xì)胞增值能力改善、凋亡減少、血清促炎因子水平增加,抗炎因子分泌減少,脾臟內(nèi)精氨酸酶和一氧化氮合酶蓄積減少。反應(yīng)到動物整體水平則是相較于CLP組,ATRA治療組小鼠DTH反應(yīng)增強(qiáng),二次細(xì)菌感染后生存時間延長、生存率提升。而ATRA對膿毒癥后期小鼠二次打擊生存預(yù)后的有利作用會被過繼回輸CLP-7d產(chǎn)生的MDSCs所中和,而用抗體耗竭膿毒癥后期小鼠體內(nèi)MDSCs則會達(dá)到與使用ATRA相似的效果。在篩選有可能參與ATRA調(diào)控MDSCs的信號傳導(dǎo)分子時發(fā)現(xiàn)STAT-3的激活程度(磷酸化水平)有明顯改變,而STAT-6和AKT這兩個指標(biāo)變化不顯著。 結(jié)論：以上研究結(jié)果提示ATRA能通過抑制MDSCs的擴(kuò)增和活性,恢復(fù)特異性免疫功能和炎癥反應(yīng)平衡,改善膿毒癥后期的免疫狀態(tài)。從而為膿毒癥后免疫抑制的治療提供新的思路。
[Abstract]:Background: sepsis is a series of complex immune responses to severe infections, from the early stage of high inflammation mediated by cytokines to the later stage of low inflammation. In the late stage of sepsis, the body is in an immunosuppressive state, which is characterized by a decrease in the ability of the body to clear the invading pathogens and an increase in susceptibility to conditional pathogens, which has become the main cause of death in sepsis patients. Myeloid-derived suppressor cells (MDSCs) are heterogeneous cells composed of immature myeloid cells. After sepsis, myeloid-derived suppressor cells will be over-expanded and activated, which can inhibit adaptive immune response by affecting T cell proliferation and function. Thus the immunosuppressive state is induced. In vitro experiments, animal carrier experiments and clinical drug trials have demonstrated that all trans retinoic acid (all-trans-retinoic) can induce differentiation and maturation of MDSCs into macrophages, dendritic cells and granulocytes so as to reduce the inhibitory effect of MDSCs on T cells. But these studies are focused on cancer and lack evidence for sepsis. This study aims to explore how ATRA regulates the expansion and function of MDSCs during sepsis, especially in the late stage of sepsis, and may be involved in signal transduction pathways. Methods: in this study, the sepsis model was established by cecal ligation and perforation of (cecal ligation and puncture. on the basis of this model, a secondary infection attack model was established by Pseudomonas aeruginosa drip nose. The number, phenotypic, morphological and immunosuppressive activity of MDSCs induced by ATRA were observed. Apoptosis and delayed hypersensitivity (delayed type hypersensitivity,), the level of inflammatory factor secretion in serum and MDSCs, and the effect of signal transduction molecules. Results the absolute number and percentage of MDSCs in spleen, peripheral blood and bone marrow were significantly decreased, argininase activity and no production of MDSCs were decreased, and the secretion balance of proinflammatory / anti-inflammatory cytokines was restored. Finally, the inhibition of CD4 T cells was alleviated. These changes bring about the improvement of immune status in the later stage of sepsis mice, which is manifested by the improvement of CD4 T cell proliferation ability, the decrease of apoptosis, the increase of serum pro-inflammatory factor level and the decrease of anti-inflammatory factor secretion. The accumulation of arginase and nitric oxide synthase in spleen decreased. Compared with the CLP group, the DTH response was increased, the survival time was prolonged and the survival rate was increased after secondary bacterial infection. The beneficial effect of ATRA on survival and prognosis of mice after sepsis was neutralized by repeated transfusion of MDSCs produced by CLP-7d, while the effect of using antibody to exhaust MDSCs in mice of late stage of sepsis was similar to that of mice treated with ATRA. In screening signal transduction molecules that may be involved in ATRA regulation of MDSCs, it was found that the activation degree of STAT-3 (phosphorylation level) changed significantly, but STAT-6 and AKT did not change significantly. Conclusion: these results suggest that ATRA can improve the immune state of sepsis by inhibiting the expansion and activity of MDSCs and restoring the balance of specific immune function and inflammatory reaction. This provides a new idea for the treatment of immunosuppression after sepsis.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：R459.7

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 姚詠明,盛志勇;膿毒癥研究的若干新動態(tài)[J];中國危重病急救醫(yī)學(xué);2000年06期

2 菲琳;;治療膿毒癥的新希望[J];國外醫(yī)學(xué)情報;2002年10期

3 向陽;防止膿毒癥自高動力相轉(zhuǎn)向低動力相的新途徑[J];國外醫(yī)學(xué).外科學(xué)分冊;2003年03期

4 任新生;重新認(rèn)識全身炎癥反應(yīng)綜合征、膿毒癥和多器官功能衰竭綜合征[J];中華急診醫(yī)學(xué)雜志;2004年02期

5 崔德健;探討膿毒癥診斷和治療新策略[J];中國呼吸與危重監(jiān)護(hù)雜志;2004年03期

6 林洪遠(yuǎn);膿毒癥診斷和治療進(jìn)展[J];中國實(shí)用外科雜志;2004年06期

7 湯耀卿;膿毒癥的定義和診斷[J];臨床外科雜志;2004年11期

8 王小平;膿毒癥研究現(xiàn)狀[J];實(shí)用臨床醫(yī)學(xué);2005年06期

9 周國勇;性別與膿毒癥嚴(yán)重程度的關(guān)系[J];中國危重病急救醫(yī)學(xué);2005年07期

10 黎永明;姜勇;;膿毒癥發(fā)生機(jī)制的新進(jìn)展[J];感染.炎癥.修復(fù);2005年01期

相關(guān)會議論文 前10條

1 張麗葳;奚希相;張威;張莉芬;陳昊;李俊;楊興易;;以血小板減少為主要表現(xiàn)的膿毒癥搶救一例[A];《中華急診醫(yī)學(xué)雜志》第八屆組稿會暨急診醫(yī)學(xué)首屆青年論壇論文匯編[C];2009年

2 張振輝;林s鉅，

本文編號：2059873