维生素E、硒对非酒精性脂肪肝大鼠肝细胞色素P4501A1及脂质过氧化的干预作用

Vitamin E and Se interfere in cytochrome P4501A1 and lipid peroxidation in nonalcoholic fatty liver diseases in rats

目的:研究维生素E、硒对非酒精性脂肪肝大鼠肝细胞色素P4501A1及脂质过氧化的干预作用.方法:♂SD大鼠,随机均分为5组:对照组(普通饲料)、模型组(高脂饲料)、VE干预组、Se干预组、VE+Se干预组,建模5wk处死全部大鼠.生化方法检测血清及肝组织超氧化物歧化酶(SOD)和丙二醛(MDA)含量的变化,逆转录聚合酶链反应(RT-PCR)测定肝细胞色素P4501A1mRNA表达的变化,免疫组化方法测定肝组织中肿瘤坏死因子-α(TNF-α)、核因子-κB(NF-κB)表达的变化.结果:与对照组比较,模型组血清及肝组织中SOD显著降低(312.72±49.51kU/Lvs583.23±63.37kU/L;8.13±0.63U/mgprot.vs13.99±2.33U/mgprot.,P<0.01),MDA增高(13.40±4.24mmol/Lvs6.43±1.76mmol/L;9.79±0.94nmol/mgprot.vs6.80±0.97nmol/mgprot.P<0.01),细胞色素P4501A1mRNA表达水平,肝组织TNF-α、NF-κB蛋白表达明显增强(0.628±0.116vs0,0.230±0.013vs0.03±0.006,0.069±0.01vs0.003±0.001;P<0.05).与模型组比较VE组、Se组的血清及肝组织中SOD增高,MDA降低,细胞色素P4501A1mRNA表达水平略下降;肝组织TNF-α、NF-κB蛋白表达下降(P<0.05).VE+Se组与模型组比较,血清SOD明显增高,其值接近对照组水平;细胞色素P4501A1mRNA表达水平显著下降(0.324±0.070vs0.628±0.116,P<0.05).结论:非酒精性脂肪肝的脂质过氧化损伤及相关因子的表达可能与肝细胞色素P4501A1表达上调有关.VitE和硒能提高机体的抗氧化能力,对非酒精性脂肪肝有保护作用,二者联合作用更明显.

AIM： To study the effects of vitamin E and Se on cytochrome P4501A1 and lipid peroxidation in nonalcoholic fatty liver diseases in rats. METHODS： Forty male SD rats were randomly divided into 5 groups： normal control group, model group, VE group, Se group and VE ＋ Se group. Each subgroup comprised 8 rats, which were respectively fed with normal diets, fatrich diets and interfering diets （VE, Se, VE ＋ Se）. All animals were sacrificed at the end of the 5th week. Superoxide dismutase （SOD） and malondialdehyde （MDA） levels in the serum and liver were detected by biochemical analysis. The expression levels of cytochrome P4501A1 mRNA in liver tissue were measured by reverse transcription polymerase chain reaction （RT-PCR）. The levels of tumor necrosis factor alpha （TNF-α） and nuclear factor kappa B （NF-κB） proteins in hepatic tissue were examined by immunohistochemistry. RESULTS： Compared with the control group,MDA levels in the serum and livers of model group animals were elevated （serum, 13.40 ± 4.24 mmol/L vs 6.43 ±1.76 mmol/L; liver, 9.79 ± 0.94 nmol/mgprot, vs 6.80 ± 0.97 nmol/mgprot., P 〈 0.01）, while SOD levels were decreased （serum, 312.72 ± 49.51 kU/L vs 583.23 ± 63.37 kU/L; liver, 8.13 ± 0.63 U/mgprot. vs 13.99 ＋ 2.33 U/mg- prof.; P 〈 0.01）. The levels of NF-κB and TNF-α proteins and cytochrome P4501A1 mRNA in liver tissue were significantly increased in model group animals （0.069 ± 0.01, 0.230 ± 0.013 and 0.628 ± 0.116, respectively） compared with control animals （0.003 ± 0.001, 0.03 ± 0.006, and 0, respectively; P 〈 0.05）. Compared with the model group, in the VE group and Se group, MDA decreased in serum and liver while SOD heightened, levels of cytochrome P4501A1 mRNA in liver tissue also decreased. Expression of NF-κB and TNF-α proteins also decreased （P 〈 0.05）. The SOD levels in the serum of VE ＋ Se group animals clearly increased, and approached the levels of the control group, compared with those in model group animals, whereas the levels of cytochrome P4501A1 mRNA in liver tissue significantly decreased （0.324 ± 0.070 vs 0.628 ± 0.116; P 〈 0.05）.CONCLUSION： Lipid peroxidation and the expression of some correlation factors in nonalcoholic fatty liver diseases is probably relevant to the up-regulation of cytochrome P4501A1 mRNA in liver tissue. Vitamin E and Se can protect against nonalcoholic fatty liver diseases owing to their antioxidant capabilities. The function of the administration of both Vitamin E and Se combined was significantly larger than those of vitamin E and sodium selenite alone.