褪黑素對乙醇致小鼠慢性肝損傷的保護(hù)作用

1、褪黑素對乙醇致小鼠慢性肝損傷的保護(hù)作用 作者：劉衛(wèi)輝，蔡川，周揚(yáng)，劉芳娥，田少華 【關(guān)鍵詞】 褪黑激素；乙醇；肝/損傷；慢性病Hepatoprotective effect of melatonin on chronically ethanoltreated mice【Abstract】 AIM: To investigate the changes of alanine aminotransferase(ALT), aspartate aminotransferase(AST), malondialdehyde (MDA) and pathological lesions of mice l

2、ivers,which were caused by chronic alcohol drinking, and the protective effect of melatonin(MT) against ethanolinduced chronic hepatotoxicity. METHODS: Fortyeight mice were randomly divided into 4 groups: control group(A), alcohol group (B), alcohol +high dosage MT group(C), and alcohol+low dosage M

3、T group(D). 60 mL/L alcohol was used to induce hepatotoxicity in these mice. MT was injected at 20 and 5 mg/kg immediately after alcohol drinking in group C and group D respectively. The activities of ALT, AST and the levels of MDA in liver homogenate were detected. And pathological lesion in liver

4、tissue was evaluated. RESULTS: MT inhibited the increasing tread of MDA in liver homogenate and lowered the levels of ALT and AST in chronically ethanoltreated mice. MDA: the content in group D and C was lower than that of group B (P0.05); ALT: the activity in group D was lower than that of group B

5、(P0.01), and the activity in group C was lower than that of group D (P0.01); AST: the activity in group D was lower than that of group B (P0.01); the activity in group C was lower than that of group D (P0.01). And in morphology MT could greatly prevent the lesions of chronically ethanoltreated mice

6、livers. Total pathological score: the score of group D was much lower than that of group B (P0.01); the score of group C was greatly lower than that of group D (P0.01). CONCLUSION: MT indeed hasa protective effect on chronic ethanolinduced mice livers, which is positively associated with MT dosage.【

7、Keywords】 melatonin, ethanol liver/injuries; chronic disease【摘要】 目的： 探討褪黑素(MT)對實(shí)驗(yàn)性慢性乙醇肝損傷小鼠脂質(zhì)過氧化、肝功能和肝臟病理組織的影響. 方法： 將48只小鼠隨機(jī)分為4組： 對照組（A組），模型組（B組），造模+高濃度MT給藥組（C組），造模+低濃度MT給藥組（D組）. 用60 mL/L乙醇制成小鼠慢性肝損傷模型，測定肝組織中丙二醛(MDA)含量、天冬氨酸轉(zhuǎn)氨酶(AST)和丙氨酸轉(zhuǎn)氨酶(ALT)的活性，切片觀察肝臟病理損害程度并評分. 結(jié)果： MT使慢性乙醇慢性肝損傷小鼠的MDA含量明顯下降，有效降低AST和

8、ALT活性，并與劑量呈正相關(guān). MDA：造模+高濃度MT給藥組和造模+低濃度MT給藥組值均明顯較模型組減低(P均0.05). ALT：造模+低濃度MT給藥組活性值明顯低于模型組(P0.01)；造模+高濃度MT給藥組活性值明顯較造模+低濃度MT給藥組減低(P0.01). AST：造模+低濃度MT給藥組活性值明顯低于模型組(P0.01)；造模+高濃度MT給藥組活性值明顯較造模+低濃度MT給藥組減低(P0.01). 病理學(xué)形態(tài)觀察顯示，MT能減輕肝臟病理損害程度，與劑量成正相關(guān). 病理損害程度評分： 造模+低濃度MT給藥組值明顯低于模型組(P0.01)；造模+高濃度MT給藥組值明顯較造模+低濃度MT

9、給藥組低(P0.01). 結(jié)論： MT對慢性乙醇肝損傷具有一定的保護(hù)作用，且與藥物劑量呈正相關(guān).【關(guān)鍵詞】 褪黑激素；乙醇；肝/損傷；慢性病0引言嗜酒已經(jīng)是日益影響人類健康的嚴(yán)重問題1，正確認(rèn)識和防治乙醇性肝病極為重要. 雖然急性乙醇中毒已有顯效藥物2，但是乙醇所致慢性肝臟損傷的有效治療藥物還很匱乏. 褪黑素(melatonin, MT）除了直接抗自由基3、抑制脂質(zhì)過氧化反應(yīng)外，還能增強(qiáng)體內(nèi)抗氧化酶的活性，從而達(dá)到對自由基的殺滅能力4. MT在體內(nèi)半衰期較短，主要代謝途徑是經(jīng)肝微粒體羥化酶催化生成6羥基褪黑素（6OH MT），6OH MT比MT有更強(qiáng)抗自由基作用5. 我們擬探討MT對小鼠慢性乙

10、醇肝損傷的保護(hù)作用，從而為乙醇致慢性肝臟損傷防治提供依據(jù).1材料和方法1.1材料健康昆明小鼠8只，體質(zhì)量1822 g，雌雄各半(第四軍醫(yī)大學(xué)實(shí)驗(yàn)動物中心)；4 MT(1 g，純度99.5%，美國Sigma公司). 將MT溶解后加生理鹽水稀釋，配成濃度分別為10 g/L和2.5 g/L溶液，即配即用. 丙二醛(MDA)、天冬氨酸轉(zhuǎn)氨酶(AST)和丙氨酸轉(zhuǎn)氨酶(ALT)試劑盒(南京建成生物工程研究所)；二鍋頭白酒（北京二鍋頭酒廠）,產(chǎn)品標(biāo)準(zhǔn)號: Q大/EGT,6021996,一級,（乙醇濃度60度，V/V)；戊巴比妥，試劑為分析純. DY89I型電動玻璃勻漿器（寧波新芝科器研究所）；MR1812離

11、心機(jī)（美國Jouan公司）；紫外分光光度計(jì)（日本島津，UV2100）；石蠟切片機(jī)；顯微鏡（日本Olympus公司BH2型）.1.2方法5 mm的小塊,放入DY89I型電動玻璃勻漿器勻漿,制成組織勻漿液6,硫代巴比妥酸比色法7測定A532 nm值. SPSS12.0統(tǒng)計(jì)軟件將A值轉(zhuǎn)換為含量值表示肝臟過氧化程度,值越高表示肝臟過氧化程度越高8.m的切片,HE染色，請校病理學(xué)教研室，由專業(yè)人員進(jìn)行Olympus BH2顯微鏡下觀察評分，從肝臟的一端視野開始記錄細(xì)胞的病理變化，用40倍物鏡連續(xù)記錄70個(gè)視野(占整個(gè)的1/2). 觀察指標(biāo)為肝脂變、肝壞死、炎細(xì)胞浸潤、纖維組織增生程度，4項(xiàng)之和為病理學(xué)總分. 其中，肝脂變、肝壞死、炎細(xì)胞浸潤的評分為： 1分（微度），2分（輕度）,3分（中度）,4分（重度）. 肝脂變按照衛(wèi)生部保健食品功效學(xué)評價(jià)標(biāo)準(zhǔn)評分. 微度： 肝細(xì)胞內(nèi)含脂滴的肝細(xì)胞不超過1/4；輕度：含脂滴的肝細(xì)胞不超過1/2；中度： 含脂滴的肝細(xì)胞不