改善胰岛素抵抗药物治疗大鼠非酒精性脂肪肝病的实验研究

目的探讨罗格列酮和二甲双胍对大鼠非酒精性脂肪肝病(NAFLD)的治疗作用。方法44只雄性SD大鼠分为正常对照组(8只)和NAFLD组(36只)。以高脂饲料饲养建立NAFLD大鼠模型,8周末,处死NAFLD组大鼠4只,证实造模成功后,将NAFLD组进一步分为4组:NAFLD对照组(8只)、罗格列酮治疗组(8只)、二甲双胍治疗组(8只)和饮食治疗组(8只),除NAFLD对照组外,其余各组均进食普通饲料。12周末,处死所有动物,检测血脂、肝功能、肿瘤坏死因子α(TNFα)、肝脂质、肝组织TNFα、脂肪酸合成酶(FAS)的mRNA表达等指标及肝组织病理学。结果罗格列酮和二甲双胍治疗组血甘油三酯(0.61mmol/L±0.17mmol/L,0.63mmol/L±0.16mmol/Lvs0.85mmol/L±0.15mmol/L),总胆固醇(2.49mmol/L±0.68mmol/L,2.49mmol/L±0.58mmol/Lvs4.55mmol/L±1.58mmol/L),肝功能(丙氨酸氨基转移酶:38.3U/L±10.6U/L,43.3U/L±27.5U/Lvs110.6U/L±44.2U/L,天冬氨酸氨基转移酶:141.7U/L±14.3U/L,174.5U/L±57.9U/Lvs251.8U/L±91.0U/L),肝组织甘油三酯含量(18.9mg/g±2.7mg/g,20.4mg/g±3.6mg/gvs54.8mg/g±7.6mg/g)均显著低于NAFLD对照组(均P<0.05),其肝脂肪变性(分级:0.8±0.3,1.0±0.2vs2.8±0.5)及炎症程度(积分:0.8±0.2,1.0±0.3vs1.8±0.4)亦显著减轻(均P<0.01)。饮食治疗也能使血脂异常和肝组织病理学改变有一定改善,但对肝功能异常和肝脏炎症改善不明显,且疗效不如两药物治疗组。罗格列酮和二甲双胍治疗组的血清TNFα(125pg/ml±21pg/ml,155pg/ml±33pg/ml vs324pg/ml±34pg/ml)及肝组织TNFαmRNA(0.24±0.14,0.30±0.12vs0.85±0.12),FAS mRNA表达水平(0.22±0.14,0.29±0.16vs0.68±0.23)亦显著低于NAFLD对照组(均P<0.05)。结论罗格列酮和二甲双胍可有效治疗大鼠NAFLD。

Therapeutic effects of insulin-sensitizing drugs on nonalcoholic fatty liver disease: experiment with rats

OBJECTIVE: To investigate the therapeutic effects of insulin-sensitizing drugs, rosiglitazone and metformin, on nonalcoholic fatty liver disease (NAFLD). METHODS: Forty-four male SD rats were randomized into 4 groups: normal control group (n = 8, fed with normal food) and NAFLD rats (n = 36, fed with high-fat food). Eight weeks later 4 rats were randomly selected from the NAFLD group and were killed to undergo pathological examination of the liver. When the establishment of experimental model of NAFLD rats was confirmed the remaining 32 NAFLD rats were subdivided into 4 equal subgroups: NAFLD control group (to be fed continuously with high-fat food), rosiglitazone treatment group (fed with normal food and rosiglitazone 1.5 mg x kg(-1) x d(-1) by gastric perfusion), metformin treatment group (fed with normal food and metformin 150 mg x kg(-1) x d(-1) by gastric perfusion), and dietary treatment group (fed with normal food and normal saline by gastric perfusion). By the end of the 12th week, all rats were killed to isolate the samples of serum to test the levels of total cholesterol (TC), triglyceride (TG), alanine transaminase (ALT), aspartate transaminase (AST), and tumor necrosis factor-alpha (TNF-alpha). Samples of liver tissue were taken to undergo pathology to examine fatty degeneration and inflammatory cell infiltration and detection of the levels of TC and TG. In the liver the weights of body and liver were measured so as to calculate the liver index. RESULTS: (1) The levels of serum TC, TG, ALT, and AST, liver TC and TG, and liver index of the NAFLD control group increased significantly, and the liver histology of the NAFLD control group expressed moderate to severe fatty degeneration. (2) The serum TC levels of the rosiglitazone and metformin groups were 2.49 mmol/L +/- 0.68 mmol/L and 2.49 mmol/L +/- 0.58 mmol/L, both significantly lower than that of the NAFLD control group (4.55 mmol/L +/- 1.58 mmol/L, both P < 0.001). The serum TG levels of the rosiglitazone and metformin groups were 0.61 mmol/L +/- 0.17 mmol/L and 0.63 mmol/L +/- 0.16 mmol/L respectively, both significantly lower than that of the NAFLD control group (0.85 mmol/L +/- 0.15 mmol/L, both P < 0.001). The serum level of ALT of the rosiglitazone and metformin groups were 38.3 U/L +/- 10.6 U/L and 43.3 U/L +/- 27.5 U/L respectively, both significantly lower than that of the NAFLD control group (110.6 U/L +/- 44.2 U/L, P < 0.001 and P < 0.05). The serum levels of AST of the rosiglitazone and metformin groups were 141.7 U/L +/- 14.3 U/L and 174.5 U/L +/- 57.9 U/L, both significantly lower than that of the NAFLD control group (251.8 U/L +/- 91.0 U/L, both P < 0.05). The liver TG levels of the rosiglitazone and metformin groups were 18.9 mg/g +/- 2.7 mg/g and 20.4 mg/g +/- 3.6 mg/g respectively, both significantly lower than that of the NAFLD control group (54.8 mg/g +/- 7.6 mg/g, both P < 0.05). The fatty degeneration grades of liver tissues of the rosiglitazone and metformin groups were grade: 0.8 +/- 0.3 and 1.0 +/- 0.2, both significantly lower than that of the NAFLD control group (grade 2.8 +/- 0.5, both P < 0.05). The hepatic inflammation scores of: the rosiglitazone and metformin groups were 0.8 +/- 0.2 and 1.0 +/- 0.3 respectively, both significantly lower than that of the NAFLD control group (1.8 +/- 0.4, both P < 0.05). The levels of abnormality in serum TC and TG, liver TG, and liver histology of the dietary treatment group were all alleviated in comparison with the NAFLD control group, but were somewhat severer than those of the rosiglitazone and metformin treatment groups. (3) The serum TNF-alpha levels of the rosiglitazone and metformin treatment groups were 124.6 pg/mL +/- 21.0 pg/mL, 154.9 pg/mL +/- 32.5 pg/mL respectively, both significantly lower than that of the NAFLD group (324.2 pg/mL +/- 34.2 pg/mL, P < 0.001 and P < 0.05). The liver TNF-alpha levels of the rosiglitazone and metformin treatment groups were 0.24 +/- 0.14 and 0.30 +/- 0.12 respectively, both significantly lower than that of the NAFLD group (0.85 +/- 0.12, both P < 0.001). The levels of FAS mRNA expression of the rosiglitazone and metformin treatment groups were 0.22 +/- 0.14 and 0.29 +/- 0.16 respectively, both significantly lower than that of the NAFLD group (0.68 +/- 0.23, P < 0.001 and P < 0.005). CONCLUSION: The insulin-sensitizing drugs, rosiglitazone and metformin, are effective in the treatment of NAFLD.