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(1.皖南醫(yī)學院第一附屬醫(yī)院 弋磯山醫(yī)院 心功能科,安徽 蕪湖 241001;2.皖南醫(yī)學院 a.生理學教研室;b.病理生理學教研室,安徽 蕪湖 241002)
·基礎醫(yī)學·
番茄紅素對膿毒血癥大鼠心肌損傷的影響
楊濤1,姜玉新2a,李偉2b,王國光2b
(1.皖南醫(yī)學院第一附屬醫(yī)院 弋磯山醫(yī)院 心功能科,安徽 蕪湖 241001;2.皖南醫(yī)學院 a.生理學教研室;b.病理生理學教研室,安徽 蕪湖 241002)
目的:觀察番茄紅素對膿毒血癥大鼠心肌損傷的影響。方法雄性SD大鼠隨機分為正常對照組(NOR)、膿毒血癥組(SEP)及番茄紅素處理組(LYC)。大鼠通過腹腔注射內毒素(20 mg/kg)制備膿毒血癥模型,番茄紅素處理組大鼠在以番茄紅素預處理2 h后腹腔注射內毒素,6 h后,收集血樣品及心臟。檢測血清炎癥細胞因子水平、抗氧化酶活性及丙二醛(MDA)含量;觀察心肌組織學變化;檢測心肌組織炎癥調節(jié)蛋白磷酸化核因子κB(p-NF-κB)、環(huán)氧酶-2(COX-2)的表達。結果與對照組比較,膿毒血癥組大鼠血清炎癥細胞因子腫瘤壞死因子-α(TNF-α)和白介素-6(IL-6)及MDA含量升高,超氧化物歧化酶(SOD)活性降低,心肌組織p-NF-κB和COX-2水平升高;番茄紅素處理明顯降低血清TNF-α和IL-6及MDA含量,提高SOD活性,降低心肌組織p-NF-κB和COX-2表達。形態(tài)觀察可見膿毒血癥組大鼠心肌纖維損傷、排列疏松,番茄紅素處理減輕了心肌纖維損傷。結論番茄紅素預處理可減輕膿毒血癥大鼠的心肌損傷,其機制可能通過下調炎癥信號NF-κB/COX-2實現。
番茄紅素;膿毒血癥;心肌損傷
膿毒血癥是由感染引起的炎癥失調而導致的全身炎癥反應綜合征,是臨床高致死率的重要原因[1]。研究認為,炎癥因子過度釋放,在膿毒血癥器官損傷中起著重要作用,并影響預后效果[2-4]。心肌是膿毒血癥損傷的重要器官,是導致膿毒血病人死亡的重要原因[5]。番茄紅素(lycopene)是一種不含氧的類胡蘿卜素,廣泛存在于番茄等紅色水果中[6]。番茄紅素有許多重要的生物學功能,研究表明,番茄紅素有抗腫瘤及抗氧化等作用[7-9],并且其血清濃度與急性心肌梗死及心源性猝死相關[10-11]。本研究旨在觀察番茄紅素對膿毒血癥大鼠心肌損傷的保護作用。
1.1 試劑與器材 番茄紅素購自南京澤朗醫(yī)藥科技有限公司(NO. 502-65-8),內毒素(Escherichia coli 0111:B4)為Sigma公司產品,SOD和MDA檢測試劑盒為南京建成生物工程研究所生產;TNF-α、IL-6特異度檢測試劑盒購自合肥博美生物工程有限公司;β-actin、磷酸化核因子κB(phosphorylation of nuclear factor kappa B,p-NF-κB)、環(huán)氧酶-2(cyclooxygenase-2,COX-2)及核因子κB(nuclear factor-kappa B,NF-κB)多克隆抗體購自上海生物工程有限公司。
1.2 動物分組與實驗方法
1.2.1 實驗設計 雄性SD大鼠(體質量260~300 g)購自南京青龍山動物養(yǎng)殖場(許可證號:SCKK2009-0001)。在1周的自由飲水、進食適應后,大鼠被隨機分為正常對照組(NOR)、膿毒血癥組(SEP)及番茄紅素處理組(LYC),每組10只。
1.2.2 動物模型復制 各組大鼠分別以腹腔注射戊巴比妥鈉(45 mg/kg)麻醉,番茄紅素處理組大鼠通過尾靜脈注射番茄紅素(50 mg/kg),正常對照及膿毒血癥組大鼠尾靜脈注射等體積溶劑。2 h后,番茄紅素處理組及膿毒血癥組大鼠通過腹腔注射內毒素(20 mg/kg),正常對照組大鼠腹腔注射生理鹽水。注射6 h后,動脈插管收集血樣品,并取心臟分別置于10%甲醛,-80℃保存。
1.2.3 SOD活性及MDA含量檢測 血樣品離心,取上清液檢測血清SOD活性及MDA含量。黃嘌呤氧化酶法檢測血清SOD活性,硫代巴比妥酸法檢測血清MDA。
1.2.4 炎性因子檢測 血清TNF-α、IL-6分別以TNF-α、IL-6特異ELISA試劑盒檢測。操作按產品說明書步驟進行。
1.2.5 組織觀察 取甲醛中固定的心肌,以石蠟包埋,制作5 μm切片,以蘇木素-伊紅(H-E)染色后,光學顯微鏡下觀察心肌形態(tài)結構的變化。
1.2.6 Western blot 取-80℃保存的心肌置于有預冷組織裂解液的勻漿器中勻漿、裂解,轉移至EP管,4℃下,以11 500 r/min轉速離心20 min。將含等量蛋白量的上清液稀釋至等體積,以10% SDS-PAGE電泳進行分離后,蛋白電泳轉至硝酸纖維素膜。膜以5%的脫脂奶粉液封閉,加β-actin、p-NF-κB、COX-2及NF-κB抗體,4℃下雜交過夜,膜以TBS-T清洗后,與Ⅱ抗孵育雜交2 h,洗膜,以DAB顯色。
2.1 SOD活性及MDA的變化 3組大鼠血清SOD活性比較(F=47.03,P<0.01)及MDA含量比較(F=66.98,P<0.01)變化差異有統(tǒng)計學意義,膿毒血癥組大鼠血清SOD活性較正常對照組降低[(183.41±13.60)U/mLvs.(132.23±10.15)U/mL,P<0.01],而MDA升高[(4.06±0.63)nmol/mLvs. (10.72± 1.74)nmol/mL,P<0.01](圖1);番茄紅素處理組較膿毒血癥組SOD活性增強[(132.23±10.15)U/mLvs.(168.06±12.33) U/mL,P<0.01],而MDA含量降低[(10.72±1.74)nmol/mLvs. (7.16±1.24) nmol/mL,P<0.01](圖1)。
**P<0.01vs. NOR;##P<0.01vs. SEP。
圖1 番茄紅素對血清SOD活性和MDA含量的影響
2.2 番茄紅素對炎性因子的影響 由圖2可知,各組大鼠血清炎性因子TNF-α(F=19.53,P<0.01)及IL-6(F=13.63,P<0.01)變化差異有統(tǒng)計學意義,與對照組比較,膿毒血癥組大鼠血清TNF-α和IL-6升高[(190.63±10.84 )ng/Lvs. (231.14±18.48) ng/L,(26.41±2.28) ng/Lvs. (32.91±3.15) ng/L,P<0.01];番茄紅素預處理較膿毒血癥組血清TNF-α和IL-6水平降低[(231.14±18.48) ng/Lvs. (193.28±13.12) ng/L,(32.91±3.15) ng/Lvs. (27.60±2.45) ng/L,P<0.01]。
**P<0.01vs. NOR;##P<0.01vs. SEP。
圖2 番茄紅素對血清炎性因子的影響
2.3 組織學變化 對照組大鼠心肌排列規(guī)則且緊密;內毒素處理使大鼠心肌纖維斷裂而出現空泡化,破壞心肌纖維排列使其疏松,心肌有炎癥細胞浸潤;番茄紅素預處理改善心肌纖維排列,減輕心肌損傷。見圖3。
圖3 心肌形態(tài)學變化
2.4 番茄紅素對p-NF-κB和COX-2表達的影響 各組大鼠心肌p-NF-κB及COX-2表達差異有統(tǒng)計學意義,內毒素處理明顯提高膿毒血癥組大鼠心肌p-NF-κB、COX-2表達;番茄紅素預處理降低內毒素誘導p-NF-κB、COX-2表達。見圖4。
圖4 番茄紅素對心肌p-NF-κB和COX-2表達的影響
膿毒血癥是由各種病原菌侵襲入血引起感染并釋放毒素(如內毒素)而導致的過度全身炎癥反應[12-13]。由于感染使炎性細胞激活釋放大量的炎癥因子,進而使炎癥反應瀑布式爆發(fā),累及全身組織器官,導致組織器官功能受損,心肌損傷而引起心功能障礙是膿毒血癥常見的并發(fā)癥,是膿毒血癥高病死率的重要因素[14]。
內毒素在膿毒血癥心肌損傷中起著非常重要的作用[15]。研究表明,感染時,大量釋放的內毒素與膜表面Toll樣受體(toll-like receptors,TLRs)結合,激活細胞內炎癥信號,促進炎性細胞因子的表達和釋放[16]。作為炎癥標志物的TNF-α、IL-6及IL-1β是重要的炎性介質,在膿毒血癥血清中升高[17]。這些炎性細胞因子參與膿毒血癥的器官損傷作用,如TNF-α可作用于心肌,使心肌纖維發(fā)生損傷[18]。番茄紅素是抗氧化作用最強的類胡蘿卜素,近年研究顯示,其還可抑制膽固醇的合成及增強機體免疫力[19-20]。本研究結果表明,注射內毒素大鼠血清TNF-α、IL-6水平升高,番茄紅素預處理降低TNF-α、IL-6水平。NF-κB被內毒素激活,進而激活COX-2,NF-κB/ COX-2信號通路通過激活炎性細胞轉錄因子促進炎性介質的表達[16]。番茄紅素預處理明顯抑制COX-2及NF-κB的激活。結果提示番茄紅素可能通過抑制NF-κB/COX-2信號降低炎性細胞因子釋放而發(fā)揮抗炎作用。
膿毒血癥釋放的內毒素增加活性氧及自由基的產生,是膿毒血癥器官損傷的重要環(huán)節(jié)。研究顯示內毒素引起的炎癥反應可誘發(fā)氧化應激,而氧化應激加強炎癥反應[21]。因此,提高機體的抗氧化作用,有利于降低炎癥反應及減輕組織損傷。作為抗氧化作用最強的類胡蘿卜素,番茄紅素降低血清MDA水平及SOD活性。結果表明,番茄紅素可降低內毒素引起的氧化應激反應。
綜上所述,番茄紅素可減輕膿毒血癥大鼠的心肌損傷,其作用機制可能是通過抑制NF-κB/COX-2信號,降低炎癥反應而發(fā)揮作用,詳細機制尚需進一步的研究。
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Effectsoflycopeneonmyocardialinjuryinratswithsepsis
YANGTao,JIANGYuxin,LIWei,WANGGuoguang
Department of Cardiac Function Test,The First Affiliated Hospital of Wannan Medical College,Wuhu 241001,China
Objective:To investigate the effects of lycopene on myocardial injury in rats with sepsis.Methods:Male Sprague-Dawley (SD) rats were randomly assigned to three groups:normal control (NOR),sepsis model (SEP),and lycopene treatment (LYC). Rat models of sepsis were induced by intraperitoneal injection of lipopolysaccharide (LPS,20 mg/Kg). Rats in LYC group were pre-treated with lycopene for 2 h,followed by intraperitoneal use of LPS. Then blood samples and hearts were collected 6 h after LPS treatment. Levels of inflammatory cytokines,including tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6),superoxide dismutase (SOD) activity,and malondialdehyde (MDA) content in serum were determined. Levels of cyclooxygenase-2 (COX-2) and phosphorylation of nuclear factor kappa B (p-NF-κB) in myocardial tissues were measured with Western blot. Myocardial tissues were processed for histological examination.Results:Compared with NOR,serum levels of TNF-α and IL-6,MDA content were significantly increased in SEP,yet SOD activity was decreased. LPS significantly led to increase of p-NF-κB and COX-2 expression in myocardial tissues,whereas lycopene pretreatment resulted in significantly decreased levels of inflammatory cytokines,and malondialdehyde (MDA) content in serum. Expressions of p-NF-κB and COX-2 in myocadial tissues were significantly decreased by lycopene. Morphological analysis indicated that lycopene was capable of alleviating the myocardial injury.Conclusion:Lycopene may protect the rats of sepsis from myocardial injury. The potential mechanisms may be associated with down regulation of the signaling of inflammatory cytokines(NF-κB/COX-2).
lycopene;sepsis;myocardial injury
1002-0217(2017)05-0-0413-04
國家自然科學基金項目(81671586)
2017-02-20
楊 濤(1986-),男,住院醫(yī)師,(電話)15855995768,(電子信箱)tt520cg@126.com;王國光,男,教授,碩士生導師,(電子信箱)guoguangw1226@sina.com,通信作者。
R 285.5;R 459.7
A
10.3969/j.issn.1002-0217.2017.05.002