二甲双胍对实验性大鼠脂肪肝的治疗作用
李岩, 阚志超, 天津市第三中心医院肝内科 天津市 300170
商国强,天津市第三中心医院病理科 天津市 300170
邵宏,天津市第三中心医院急症科 天津市 300170
李岩,男, 1973-01-09生, 天津市人, 汉族, 1996年天津医科大学临床医学本科毕业, 现为天津医科大学2002级消化内科研究生, 主要从事肝病方面研究.
通讯作者:阚志超, 300170, 天津市第三中心医院肝内科. li_yan629@yahoo.com.cn
, http://www.100md.com
电话: 022-84112181
收稿日期: 2005-04-26 接受日期: 2005-05-06
Therapeutic effects of metformin on rats with fattyliver
Yan Li, Zhi-Chao Kan, Guo-Qiang Shang, Hong Shao
Yan Li, Zhi-ChaoKan, Department of Gastroenterology, the Third Central Hospital of Tianjin, Tianjin 300170, China
Guo-Qiang Shang, Department of Pathology, the Third Central Hospital of Tianjin, Tianjin 300170, China
, 百拇医药
Hong Shao, Department of Emergency Management, the Third Central Hospital of Tianjin, Tianjin 300170, China
Correspondence to: Zhi-Chao Kan, Department of Gastroenterology, the Third Central Hospital of Tianjin, Tianjin 300170,China. li_yan629@yahoo.com.cn
Received: 2005-04-26 Accepted: 2005-05-06
Abstract
AIM: To investigate the changes of the liver function, histology, fatty metabolism and contents of insulin and leptin after treated with metformin in rats with fatty liver.
, 百拇医药
METHODS: Thirty-two male Wistar rats were randomly devided into three groups: control group (n = 10), model group (n = 11) and metformin group (n = 11). During the whole experiment, the rats in control group were fed with normal food, and the rats in the other two groups were fed with a high caloric laboratory chow. Then the rats in the metformin group were given metformin 170 mg/(kg·qd) while the ones in the other groups were given distilled water of the same volume by stomach irrigation for eight weeks. Then a11 the animals were sacrificed. Liver index (1iver/body weight ratio), Activities of serum liver-associated enzymes, blood lipids, free fatty acids (FFA), leptin, fasting blood glucose (FBG), fasting plasma insulin (FPI), HOMA insulin resistance index (HOMA-IR), liver triglycerides, liver cholesterol, liver tissue malondialdehyde (MDA), superoxide dismutase (SOD) and the liver histology of rats in all the groups were detected and analyzed.
, 百拇医药
RESULTS: Significant insulin resistance, disorder of fatty metabolism and liver function and increased expression of leptin were detected in rats of model group. FBG and FPI showed an increasing tendency, but there was no significant difference among the three groups. The liver histology in the model group showed moderate to severe steatosis. After treated with metformin, the levels of serum ALT (1 184.40±244.38 vs 819.83±143.86 nkat/L, P<0.05), AST (3 802.76±1 532.81 vs 2 959.26±540.44 nkat/L, P<0.05), TG (2.28±0.50 vs 1.17±0.36 mmol/L, P<0.05) were decreased significantly. HOMA-IR (15.20±7.96 vs 13.10±5.22, P<0.05) in the metformin group were significantly lower, and the levels of serum leptin (2.47±0.21 vs 2.19±0.20 mg/L, P<0.05) decreased markedly. The liver histology in the metformin group was improved significantly.
, http://www.100md.com
CONCLUSION: Metformin is effective in the treatment of rats with fatty liver induced by high fat feeding.
Key Words: Metformin; Rat; Leptin; Fatty liver; Insulin resistence
Li Y, Kan ZC, Shang GQ, Shao H. Therapeutic effects of metformin on rats with fatty liver. Shijie Huaren Xiaohua Zazhi 2005;13(9):1102-1105
摘要
目的:观察二甲双胍治疗脂肪肝大鼠在生化、病理、脂肪代谢、胰岛素及瘦素各方面指标的变化.
, http://www.100md.com
方法:雄性Wistar大鼠32只，按体重层次随机分为3组，对照组(A)10只、模型组(B)11只、二甲双胍组(C)11只，对照组饲以普通鼠饲料，其余两组均饲以高脂饲料.饲养8 wk后病理证实脂肪肝已形成.随后进行灌胃治疗，C组170 mg/(kg·d)每天1次5 mL灌胃，A组及B组大鼠灌服等量蒸馏水，各组按原饲料进行饲养.8 wk后，全部处死，取血及肝组织，测定血中ALT、AST、TG、CHO、INS 、FBS、FFA、Leptin.肝组织匀浆测定肝组织TC，TG，SOD、MDA.观察肝脏组织学变化.
结果:脂肪肝大鼠存在明显脂肪代谢紊乱，肝功能异常，胰岛素抵抗及leptin表达增高;二甲双胍能显著改善肝功能，ALT(1 184.40±244.38 vs 819.83±143.86 nkat/L，P<0.05)，AST(3 802.76±1 532.81 vs 2 959.26±540.44 nkat/L，P<0.05)、降低血甘油三酯(2.28±0.50 vs 1.17±0.36 mmol/L，P<0.05)，降低leptin高表达(2.47±0.21 vs 2.19±0.20 mg/L，P<0.05)、改善胰岛素抵抗(15.20±7.96 vs 13.10±5.22，P<0.05)，并改善肝组织学.
, 百拇医药
结论:二甲双胍对实验性大鼠脂肪肝有一定治疗效果.
关键词:二甲双胍; 大鼠; 脂肪肝; 胰岛素抵抗; 瘦素
李岩, 阚志超, 商国强, 邵宏. 二甲双胍对实验性大鼠脂肪肝的治疗作用. 世界华人消化杂志 2005;13(9):1102-1105
:正常对照组; B:模型组; C:二甲双胍组.
3 讨论瘦素(leptin)是由Ob基因编码，脂肪组织分泌的肽类激素.1998年由Potter et al[8]在活化的肝星状细胞中发现leptin的mRNA和蛋白.瘦素的主要作用是调节机体脂肪的稳定，还可以调节胰岛素、肾上腺素、生长激素、甲状腺素的分泌，促进生殖、造血、免疫及血管增生，并且具有排钠利尿作用[9].Tobeet al[10]在研究血浆leptin水平与脂肪肝关系实验中发现.脂肪肝患者血浆leptin水平明显高于对照组，而且与转氨酶的升高平行.
, 百拇医药
我们通过高脂饮食成功复制出大鼠脂肪肝模型，模型组动物转氨酶水平、血脂、肝脂、胰岛素抵抗指数、血清MDA、leptin均明显升高.这与国内外文献报道相一致.血糖及胰岛素水平未见明显差别可能与喂养时间较短有关.
二甲双胍是双胍类降糖药物，通过改善胰岛素敏感程度，促进外周组织摄取葡萄糖而起到降糖作用.本实验中脂肪肝大鼠模型，虽然血糖及胰岛素水平升高，但无显著性差异.经过计算胰岛素抵抗指数较正常组明显升高且有统计学意义，提示其已存在胰岛素抵抗.通过二甲双胍治疗，转氨酶下降，血脂、肝脂、胰岛素抵抗指数下降，与治疗前有明显差异，肝组织学基本恢复正常，提示二甲双胍对实验性大鼠脂肪肝有效.而血清胆固醇无明显下降可能与用药时间较短有关.治疗后，大鼠肝组织MDA下降，SOD升高(P<0.05)，提示肝内脂质过氧化程度减轻，抗氧化物质增多.
进年来研究表明，与脂肪肝发病及胰岛素抵抗密切相关.肥胖时，leptin水平升高，有效生物学作用明显下降，胰岛素水平亦明显升高，出现胰岛素抵抗.leptin抵抗可能参与了肝脏脂肪变性的形成[11-12].我们发现模型组动物体重增加，leptin明显升高，提示有leptin抵抗.Kieffer et al[13]通过突变鼠体外培养胰岛b细胞试验，发现了leptin对突变鼠胰岛b细胞的胰岛素抑制不足，可导致高胰岛素血症、胰岛素抵抗.Seufert et al[14]认为在脂肪组织与胰岛之间可能存在“脂肪—胰岛内分泌轴”，脂肪组织与胰岛之间通过瘦素与胰岛素形成一个双向反馈环.但在病理状态下，胰岛素对leptin的敏感性下降，由于leptin和胰岛素之间相互作用，出现高leptin、高胰岛素水平.与肥胖有关的高循环leptin水平可能是通过两个步骤引起肝脏脂肪变性:(1)促进胰岛素抵抗，提高胰岛素水平;(2)改变肝细胞的胰岛素信号，增加肝细胞内脂肪酸含量[4].经过二甲双胍治疗后，leptin降低，其机理可能与胰岛素抵抗改善、血脂降低等多方面因素有关.但二甲双胍治疗与leptin之间的具体关系尚需要进一步研究.
, 百拇医药
4 参考文献1 Cortez-Pinto H, Camilo ME, Baptista A, De Oliveira AG, De Moura MC. Non-alcoholic fatty liver: anotherfeature of the
metabolic syndrome. Clin Nutr 1999;18:353-358
2 Sanya1 AJ, Campbell-Sargent C, Mirshahi F, Rizzo WB, Contos MJ,Sterlin RK, Luketic VA, Shiffman ML, Clore JN.
Nonalcoholic steato hepatitis: Associationof Insulin resistance and mitochondrial abnormalities. Gastroenterology
, 百拇医药
2001;120:1183-1192
3 Marchesini G, Brizi M, Bianchi G, Tommasetti S, Bugianesi E, LenziM, McCullough AJ, Natale S, Forlani G, Melchionda N.
Nonalcoholic fatty liver disease: a featureof the metabolic syndrome. Diabetes 2001;50:1844-1850
4 Kaplan LM . Leptin,obesity, and liver disease. Gastroenterology 1998;115:997-1001
5 Nair S, Diehi AM, Wiseman M, Farr GH Jr, Perrillo RP. Metformin inthe treatment of non-alcoholic steatohepatitis:
, http://www.100md.com
a pilot open label trial. AlimentPharmacol Ther 2004;20:23-28
6 高志强, 陆付耳, 董慧, 徐丽君, 王开富, 邹欣. 二甲双胍干预高脂饲养所致大鼠脂肪肝的研究.
中华肝脏病杂志 2005;13:101-104
7 Kanauchi M. A new index of insulin sensitivity obtained from theoral glucose tolerance test applicable to advanced
type 2 diabetes. Diabetes Care 2002;25:1891-1892
8 Potter JJ, Womak L, Mezey E, Anania FA. Transdifferentiation of rathepaic stellate cells results in leptin expression.
, 百拇医药
Biochem Biophys Res Commun 1998;244:178-182
9 Collins S, Kuhn CM, Petro AE, Swick AG, Chrunyk BA, Surwit RS. Roleof leptin in fat regultion. Nature 1996;380:677
10 Tobe K, Ogura T, Tsukamoto C, Imai A, Matsuura K, Iwasaki Y,Shimomura H, Higashi T, Tsuji T. Relationship
between serum leptin and fatty liverin Japnese male adolescent university students. Am J Gastroenterol
, 百拇医药
1999;94:3328-3335
11 Chitturi S, Farrell G, Frost L, Kriketos A, Lin R, Fung C, LiddleC, Samarasinghe D, George J . Serum leptin in NASH
corrlates with hepatic steatosis but not fibrosis:a manifestation oflipotoxicity. Hepatology 2002;36:403-409
12 Campillo B, Sherman E, Richardet JP, Bories PN. Serum leptin levelsin alcoholic liver cirrhosis:relationship with gender,nutritional status, liver functionand energy metabolism. Eur J Clin Nutr 2001;55:980-988
, 百拇医药
13 Kieffer TJ, Heller RS, Leech CA, Holz GG, Habener JF. Leptinsuppression of insulin secretion by the activation of
ATP- sensitive K+ channels inpancreatic b cells . Diabetes 1997;46:1087-1093
14 Seufert J, Kieffer TJ, Leech CA, Holz GG, Moritz W, Ricordi C,Habener JF. Leptin suppression of insulin secretion and
gene expression in human pancreaticislets: Implications for the development of adipogenic diabetes mellitus.
J Clin Endocrinol Metab 1999;84:670
编辑 张海宁, http://www.100md.com( 李 岩,阚志超,商国强, 邵 宏)
商国强,天津市第三中心医院病理科 天津市 300170
邵宏,天津市第三中心医院急症科 天津市 300170
李岩,男, 1973-01-09生, 天津市人, 汉族, 1996年天津医科大学临床医学本科毕业, 现为天津医科大学2002级消化内科研究生, 主要从事肝病方面研究.
通讯作者:阚志超, 300170, 天津市第三中心医院肝内科. li_yan629@yahoo.com.cn
, http://www.100md.com
电话: 022-84112181
收稿日期: 2005-04-26 接受日期: 2005-05-06
Therapeutic effects of metformin on rats with fattyliver
Yan Li, Zhi-Chao Kan, Guo-Qiang Shang, Hong Shao
Yan Li, Zhi-ChaoKan, Department of Gastroenterology, the Third Central Hospital of Tianjin, Tianjin 300170, China
Guo-Qiang Shang, Department of Pathology, the Third Central Hospital of Tianjin, Tianjin 300170, China
, 百拇医药
Hong Shao, Department of Emergency Management, the Third Central Hospital of Tianjin, Tianjin 300170, China
Correspondence to: Zhi-Chao Kan, Department of Gastroenterology, the Third Central Hospital of Tianjin, Tianjin 300170,China. li_yan629@yahoo.com.cn
Received: 2005-04-26 Accepted: 2005-05-06
Abstract
AIM: To investigate the changes of the liver function, histology, fatty metabolism and contents of insulin and leptin after treated with metformin in rats with fatty liver.
, 百拇医药
METHODS: Thirty-two male Wistar rats were randomly devided into three groups: control group (n = 10), model group (n = 11) and metformin group (n = 11). During the whole experiment, the rats in control group were fed with normal food, and the rats in the other two groups were fed with a high caloric laboratory chow. Then the rats in the metformin group were given metformin 170 mg/(kg·qd) while the ones in the other groups were given distilled water of the same volume by stomach irrigation for eight weeks. Then a11 the animals were sacrificed. Liver index (1iver/body weight ratio), Activities of serum liver-associated enzymes, blood lipids, free fatty acids (FFA), leptin, fasting blood glucose (FBG), fasting plasma insulin (FPI), HOMA insulin resistance index (HOMA-IR), liver triglycerides, liver cholesterol, liver tissue malondialdehyde (MDA), superoxide dismutase (SOD) and the liver histology of rats in all the groups were detected and analyzed.
, 百拇医药
RESULTS: Significant insulin resistance, disorder of fatty metabolism and liver function and increased expression of leptin were detected in rats of model group. FBG and FPI showed an increasing tendency, but there was no significant difference among the three groups. The liver histology in the model group showed moderate to severe steatosis. After treated with metformin, the levels of serum ALT (1 184.40±244.38 vs 819.83±143.86 nkat/L, P<0.05), AST (3 802.76±1 532.81 vs 2 959.26±540.44 nkat/L, P<0.05), TG (2.28±0.50 vs 1.17±0.36 mmol/L, P<0.05) were decreased significantly. HOMA-IR (15.20±7.96 vs 13.10±5.22, P<0.05) in the metformin group were significantly lower, and the levels of serum leptin (2.47±0.21 vs 2.19±0.20 mg/L, P<0.05) decreased markedly. The liver histology in the metformin group was improved significantly.
, http://www.100md.com
CONCLUSION: Metformin is effective in the treatment of rats with fatty liver induced by high fat feeding.
Key Words: Metformin; Rat; Leptin; Fatty liver; Insulin resistence
Li Y, Kan ZC, Shang GQ, Shao H. Therapeutic effects of metformin on rats with fatty liver. Shijie Huaren Xiaohua Zazhi 2005;13(9):1102-1105
摘要
目的:观察二甲双胍治疗脂肪肝大鼠在生化、病理、脂肪代谢、胰岛素及瘦素各方面指标的变化.
, http://www.100md.com
方法:雄性Wistar大鼠32只，按体重层次随机分为3组，对照组(A)10只、模型组(B)11只、二甲双胍组(C)11只，对照组饲以普通鼠饲料，其余两组均饲以高脂饲料.饲养8 wk后病理证实脂肪肝已形成.随后进行灌胃治疗，C组170 mg/(kg·d)每天1次5 mL灌胃，A组及B组大鼠灌服等量蒸馏水，各组按原饲料进行饲养.8 wk后，全部处死，取血及肝组织，测定血中ALT、AST、TG、CHO、INS 、FBS、FFA、Leptin.肝组织匀浆测定肝组织TC，TG，SOD、MDA.观察肝脏组织学变化.
结果:脂肪肝大鼠存在明显脂肪代谢紊乱，肝功能异常，胰岛素抵抗及leptin表达增高;二甲双胍能显著改善肝功能，ALT(1 184.40±244.38 vs 819.83±143.86 nkat/L，P<0.05)，AST(3 802.76±1 532.81 vs 2 959.26±540.44 nkat/L，P<0.05)、降低血甘油三酯(2.28±0.50 vs 1.17±0.36 mmol/L，P<0.05)，降低leptin高表达(2.47±0.21 vs 2.19±0.20 mg/L，P<0.05)、改善胰岛素抵抗(15.20±7.96 vs 13.10±5.22，P<0.05)，并改善肝组织学.
, 百拇医药
结论:二甲双胍对实验性大鼠脂肪肝有一定治疗效果.
关键词:二甲双胍; 大鼠; 脂肪肝; 胰岛素抵抗; 瘦素
李岩, 阚志超, 商国强, 邵宏. 二甲双胍对实验性大鼠脂肪肝的治疗作用. 世界华人消化杂志 2005;13(9):1102-1105
:正常对照组; B:模型组; C:二甲双胍组.
3 讨论瘦素(leptin)是由Ob基因编码，脂肪组织分泌的肽类激素.1998年由Potter et al[8]在活化的肝星状细胞中发现leptin的mRNA和蛋白.瘦素的主要作用是调节机体脂肪的稳定，还可以调节胰岛素、肾上腺素、生长激素、甲状腺素的分泌，促进生殖、造血、免疫及血管增生，并且具有排钠利尿作用[9].Tobeet al[10]在研究血浆leptin水平与脂肪肝关系实验中发现.脂肪肝患者血浆leptin水平明显高于对照组，而且与转氨酶的升高平行.
, 百拇医药
我们通过高脂饮食成功复制出大鼠脂肪肝模型，模型组动物转氨酶水平、血脂、肝脂、胰岛素抵抗指数、血清MDA、leptin均明显升高.这与国内外文献报道相一致.血糖及胰岛素水平未见明显差别可能与喂养时间较短有关.
二甲双胍是双胍类降糖药物，通过改善胰岛素敏感程度，促进外周组织摄取葡萄糖而起到降糖作用.本实验中脂肪肝大鼠模型，虽然血糖及胰岛素水平升高，但无显著性差异.经过计算胰岛素抵抗指数较正常组明显升高且有统计学意义，提示其已存在胰岛素抵抗.通过二甲双胍治疗，转氨酶下降，血脂、肝脂、胰岛素抵抗指数下降，与治疗前有明显差异，肝组织学基本恢复正常，提示二甲双胍对实验性大鼠脂肪肝有效.而血清胆固醇无明显下降可能与用药时间较短有关.治疗后，大鼠肝组织MDA下降，SOD升高(P<0.05)，提示肝内脂质过氧化程度减轻，抗氧化物质增多.
进年来研究表明，与脂肪肝发病及胰岛素抵抗密切相关.肥胖时，leptin水平升高，有效生物学作用明显下降，胰岛素水平亦明显升高，出现胰岛素抵抗.leptin抵抗可能参与了肝脏脂肪变性的形成[11-12].我们发现模型组动物体重增加，leptin明显升高，提示有leptin抵抗.Kieffer et al[13]通过突变鼠体外培养胰岛b细胞试验，发现了leptin对突变鼠胰岛b细胞的胰岛素抑制不足，可导致高胰岛素血症、胰岛素抵抗.Seufert et al[14]认为在脂肪组织与胰岛之间可能存在“脂肪—胰岛内分泌轴”，脂肪组织与胰岛之间通过瘦素与胰岛素形成一个双向反馈环.但在病理状态下，胰岛素对leptin的敏感性下降，由于leptin和胰岛素之间相互作用，出现高leptin、高胰岛素水平.与肥胖有关的高循环leptin水平可能是通过两个步骤引起肝脏脂肪变性:(1)促进胰岛素抵抗，提高胰岛素水平;(2)改变肝细胞的胰岛素信号，增加肝细胞内脂肪酸含量[4].经过二甲双胍治疗后，leptin降低，其机理可能与胰岛素抵抗改善、血脂降低等多方面因素有关.但二甲双胍治疗与leptin之间的具体关系尚需要进一步研究.
, 百拇医药
4 参考文献1 Cortez-Pinto H, Camilo ME, Baptista A, De Oliveira AG, De Moura MC. Non-alcoholic fatty liver: anotherfeature of the
metabolic syndrome. Clin Nutr 1999;18:353-358
2 Sanya1 AJ, Campbell-Sargent C, Mirshahi F, Rizzo WB, Contos MJ,Sterlin RK, Luketic VA, Shiffman ML, Clore JN.
Nonalcoholic steato hepatitis: Associationof Insulin resistance and mitochondrial abnormalities. Gastroenterology
, 百拇医药
2001;120:1183-1192
3 Marchesini G, Brizi M, Bianchi G, Tommasetti S, Bugianesi E, LenziM, McCullough AJ, Natale S, Forlani G, Melchionda N.
Nonalcoholic fatty liver disease: a featureof the metabolic syndrome. Diabetes 2001;50:1844-1850
4 Kaplan LM . Leptin,obesity, and liver disease. Gastroenterology 1998;115:997-1001
5 Nair S, Diehi AM, Wiseman M, Farr GH Jr, Perrillo RP. Metformin inthe treatment of non-alcoholic steatohepatitis:
, http://www.100md.com
a pilot open label trial. AlimentPharmacol Ther 2004;20:23-28
6 高志强, 陆付耳, 董慧, 徐丽君, 王开富, 邹欣. 二甲双胍干预高脂饲养所致大鼠脂肪肝的研究.
中华肝脏病杂志 2005;13:101-104
7 Kanauchi M. A new index of insulin sensitivity obtained from theoral glucose tolerance test applicable to advanced
type 2 diabetes. Diabetes Care 2002;25:1891-1892
8 Potter JJ, Womak L, Mezey E, Anania FA. Transdifferentiation of rathepaic stellate cells results in leptin expression.
, 百拇医药
Biochem Biophys Res Commun 1998;244:178-182
9 Collins S, Kuhn CM, Petro AE, Swick AG, Chrunyk BA, Surwit RS. Roleof leptin in fat regultion. Nature 1996;380:677
10 Tobe K, Ogura T, Tsukamoto C, Imai A, Matsuura K, Iwasaki Y,Shimomura H, Higashi T, Tsuji T. Relationship
between serum leptin and fatty liverin Japnese male adolescent university students. Am J Gastroenterol
, 百拇医药
1999;94:3328-3335
11 Chitturi S, Farrell G, Frost L, Kriketos A, Lin R, Fung C, LiddleC, Samarasinghe D, George J . Serum leptin in NASH
corrlates with hepatic steatosis but not fibrosis:a manifestation oflipotoxicity. Hepatology 2002;36:403-409
12 Campillo B, Sherman E, Richardet JP, Bories PN. Serum leptin levelsin alcoholic liver cirrhosis:relationship with gender,nutritional status, liver functionand energy metabolism. Eur J Clin Nutr 2001;55:980-988
, 百拇医药
13 Kieffer TJ, Heller RS, Leech CA, Holz GG, Habener JF. Leptinsuppression of insulin secretion by the activation of
ATP- sensitive K+ channels inpancreatic b cells . Diabetes 1997;46:1087-1093
14 Seufert J, Kieffer TJ, Leech CA, Holz GG, Moritz W, Ricordi C,Habener JF. Leptin suppression of insulin secretion and
gene expression in human pancreaticislets: Implications for the development of adipogenic diabetes mellitus.
J Clin Endocrinol Metab 1999;84:670
编辑 张海宁, http://www.100md.com( 李 岩,阚志超,商国强, 邵 宏)
