| Nonalcoholic fatty liver disease (NAFLD) is due to liver lesions caused byabnormal lipid metabolism disorders,and the exclusion of a history of excessivedrinking and other clear factors of liver damage. NAFLD in the tissue pathology ismanifested in the following forms: simple fatty liver, steatohepatitis, fibrosis andcirrhosis of the liver, these forms can be alone or mixed, thus NAFLD hasdiversification in clinic symptoms. When disease progressed to steatohepatitisstage, it is easy to continue the development of fatty liver fibrosis and cirrhosis.In the present study, through a model of NAFLD in rats fed high fat diet by aphysiological feeding way,and to establish an in vitro cells model of NAFLD withhuman hepatocyte strain L-02by treating with oleic acid,while the NAFLD modelfor preventive intervention with α-AL, we observed the activity of xanthine oxidase(XOD) and paraoxonase1(PON1),and the effects of α-LA on NAFLD rats in vivoand in vitro,and investagate the relevance of the activity of XOD and PON1withthe severity of NAFLD. A model of NAFLD in rats was established by intaking HFD.Controlgroup,NAFLD model group,NAFLD with α-LA (α-LA:20,40mg/kg)group wererandomly established,8rats for each group. The experiment lasted for12weeks,blood and livers were collected then. Blood fat index (triglyceride(TG), totalcholesterol(TC), high density lipoprotein cholesterol (HDL-C), low densitylipoprotein cholesterol(LDL-C）, free fatty acid(FFA）)were mesured; liver index(LI)was calculated; hepatic lipid index (TG、TC、FFA)were measured; and oxidativestress index consist of xanthine oxidase (XOD), paraoxon-1(PON1),malondialdehyde(MDA), superoxide dismutase(SOD), catalas e (CAT), glutathionea(GSH), glutathionea peroxidse (GSH-Px), total antioxidant capacity (TAOC) inblood and liver were detected. Liver specimens were taken immediately after the ratswere sacrificed. Hepatic specimens were used H﹠E staining and light microscopy formorphological analysis. The results showed that rats induced by HFD for12weeks,the model group induced obvious NAFLD associated symptoms,namely blood lipiddisorders,hepatic fat deposition and oxidative stress damage. The model group with asignificant boost of TG and FFA content, and an increase of XOD activity and MDAcontent,at the same time accompanied with a significant reduction of PON1activity.Compared with the model group,rats in-LA groups,liver index was improvedmarkedly,α-LA medication alleviated hepatic lipidosis and decreased TG,FFA levelin HFD induced NAFLD rats, and could obviously decreased XOD activity, enhancePON1activity. Morphological evaluation revealed that rats fed with HFD for12weeks developed a high degree of steatosis in model group, meanwhile,the α-LAgroups had much less as well as lower size vacuoles compared with the modelgroup.α-LA has the protective effects on NAFLD rats; the mechanism may be relatedto the inhibition of oxidative stress and anti-lipid peroxidative. The cell model of hepatocyte steatosis in vitrol was induced by treating L-02cellwith oleic acid for24hours. The fatty droplets in cells were observed by oil red Ostaining under electron microscope and were used to estimated the cell model ofNAFLD.The cells were divided into6groups: normal control group(Control),OAmodel group(M), OA+α-LA(50,100,200,400mol/L) groups, six holes for each group.24hours after culturing culturing, medicines were added respectively according todivided groups.24hours after medicines treatment,collect cells for the MTT vialitydetection, and cellular TG and FFA content, redox indexs(XOD、PON1) aftervarious concentrations of α-LA (50,100,200,400mole/L) combined use of the factorthat relative to NAFLD(OA) in L-02cells for24h, and to investigate the effect andmechanism of α-LA on the formation of NAFLD in L-02cells. The results showedthat：（1）By means of oil red O staining to observing the lipid droplets in cells andMTT method,OA with60g/mL is the best concentration for the model ofhepatocyte steatosis,because it has no significant effect on the cellular activity andsignificant accumulation of red lipid droplets in hepatocytes.(2)TG and FFA contentin hepatocytes increased significantly and manifest lipids depositon after culturedwith OA of60g/mL for24hours, which indicated that hepatocyte steatosis modelwas established and associated with lipid disorders.（3）α-LA reversed the increasedFFA induced by OA, also reduced the accumulation of intracellular lipid dropletsinduced by OA in L-02cells.(4) OA used in L-02cells induced an imbalanced redoxstate, the activity of XOD increased and with a declined of PON1activity. Afterα-LA treatement at different concentration in L-02cells for24h, and compared withthe model group, oxidative stress showed a reversal result, the activity of XODdecreased in different degrees and PON1is the opposite. Clinical results showed that XOD activity of NAFLD patients was higher andPON1activity was lower than normal. With the rise the severity level, XOD activitywas raised and PON1was lower.The results above demonstrate that there is higher activity of XOD and loweractivity of PON1as well as an obvious difference between different stages ofNAFLD than normal ones. The modeling time longer is,the higher XOD activityis,the lower activity of PON1is, and there is a more serious oxidative stress. Theimportant contributors to the occurrence and development of both XOD and PON1inNAFLD is further turned out. The activity of two kinds of enzyme was significantlyimproved in-LA treated group, and-LA has protective effects on NAFLD both invivo and invitro,the potential mechanism may be involved in its properties such asanti-lipid peroxidative and resisting oxidative stress. The change of activity withXOD and PON1may be one of the expression of oxidative stress damage in NAFLD,oxidative stress and NAFLD were closely correlated with each other, the results ofthis study suggest that the serum XOD and PON1activity might be a promising andnoninvastive approach marker for detecting the severity of NAFLD used in clinical. |
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