补锌对酒精性肝病的影响及其分子机制

Zinc supplementation effects on alcoholic liver disease and the molecular mechanism

目的:本研究是为了观察饮食补充锌减轻酒精性肝病损伤的作用及与HNF-4α的关系。方法:选用成年C57BL/6小鼠40只,按随机数字表分为4组(n=10):正常对照组、酒精中毒组、正常补锌组及酒精补锌组,用不同饮食喂养6个月处死,在正常补锌组和酒精补锌组小鼠饮用水中加入硫酸锌,使锌的含量达到75 mg/L。取各组小鼠肝组织进行病理切片及增殖细胞核抗原(PCNA)免疫组织化学染色,RT-PCR检测肝细胞核因子-4α(HNF-4α)含量,Western blot检测肝组织HNF-4α蛋白表达,检测"肝组织超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量"。结果:酒精中毒组小鼠HNF-4α转录及表达均明显低于正常对照组,差异具有统计学意义(P<0.05),该组小鼠MDA含量增高,SOD活性下降与正常对照组相比差异有统计学意义(P<0.05);而酒精补锌组小鼠PCNA阳性肝细胞数目及HNF-4α蛋白表达水平明显高于酒精中毒组,差异有统计学意义(P<0.05),该组小鼠SOD活性增加,MDA下降,与酒精中毒组相比差异有统计学意义(P<0.05)。结论:长期酒精喂养导致小鼠氧化还原失衡,而补锌可逆转该状态。我们推测饮食补锌可能是通过增加HNF-4α的转录及表达而增强酒精喂养小鼠的肝再生,因此,饮食补锌可能对酒精性肝病有较好的影响。

Objective： To examine dietary zinc supplementation could alleviate the damage of alcoholic liver disease and the relationship with the expression of hepatocyte nuclear factor 4α（HNF-4α）.Methods： 40 adult C57 BL/6 mice were randomly divided into four groups（n=10）： control,zinc,ethanol and zinc plus ethanol,which were sacrificed after fed four different diets for 6 months.Zinc sulfate was added in the drinking water of the Zinc and Zinc Plus Ethanol group and the content was 75mg/L.Liver regeneration was assessed by immunohistochemical staining of proliferating cell nuclear antigen（PCNA）,and the expression of HNF-4α was determined by RT-PCR and Western blot.And as to assess the status of oxidative stress of the mice,malondialdehyde（MDA） and superoxide dismutase（SOD） were detected.Results： Compared with the control group,the expression level of HNF-4α decreased significantly in the ethanol group（P0.05）,and the content of MDA increased significantly in this group,while the content of SOD declined significantly（P0.05）.Compared with the ethanol group,the number of PCNA-positive hepatocytes increased significantly,and the expression level of HNF-4α also increased in the zinc plus ethanol group（P0.05）,and the content of SOD increased in this group,while MDA decreased significantly（P0.05）.Conclusion： Long term ethanol exposure can lead to oxidoreduction imbalances which can be reversed by zinc supplementation.We suppose that zinc-enhanced liver regeneration is associated with an increase in HNF-4α,suggesting that dietary zinc supplementation may have beneficial effects in alcoholic liver disease.