The Effect Of Adiponectin On P38MAPK And LPL In The Oleic Acid-induced Steatosis Hepatocyte

Background and ObjectiveNon-alcoholic fatty liver disease (NAFLD) is a common liver disease which refers a clinical syndrome with the steatosis of parenehymal liver cells and lipid storage in liver without heavy alcohol intake history. In the West, the incidence of NAFLD is about 20%-40%.In China,it is one of the common disease in recently 10 years.It is a important issue about the epitology, prevention and treatment of NAFLD. However,its pathogenesis has remained unclear. Insulin resistance (IR) is one of the important foundation of NAFLD formation.Moreover,adiponectin and its receptor is closely asscoiated with IR and glugose metabolism.The previous papers suggest that p38MAPK passway induced adiponectin leat to the process of the fat acid oxide and input glugose.Therefore, adiponectin plays an important role in the mechanism of NAFLD.Meanwhile,p38MAPK passway and LPL are the dominant factors in this process.So,we explore the effect and possible mechanism of adiponectin on the expression of p38mapk and LPL during the hepatosteatosis .MethodsHuman L-02 hepatocyte were randomly divided into 3 groups.①Group A: normal hepatocyte;②Group B: oleic acid-induced group, which incubated in complete medium and oleic acid;③Group C: oleic acid plus Adiponcetin group, which incubated in normal culture medium and oleic acid and Adiponcetin. A model of oleic acid-induced steatosis of human hepatocytes was established. The accumulation of lipid droplets in hepatocytes was observed by light microscopy after oil red-O staining. The expressions of LPL mRNA of each group was detected by RT-PCR. The expressions of p38mapk, Phosphor p38mapk ( p - p38mapk) and LPL proteins of each group was detected by Western blotting. The content of triglyceride (TG) in hepatocytes was also determined.by biological and chemical detection kit of each group .Results: 1. The model of oleic acid-induced steatosis of L-02 strain hepatocytes was established successfully. In control,after oil red-O staining ,it was not observed red lipid droplets in hepatocytes,distributing densely with clear cytoplasm and nuclei.While in group B,it was found a few steatotic hepatocytes in 24hr ,as well as massive red lipid droplets in the cytoplasm in 72hr ,compare with group B, steatositic hepatocytes was significantly decrease in group C.2. TG, ALT, AST of the group B had increasing tendency time-dependently. The value of TG, ALT, AST of each observing time among the NAFLD group were different significantly (P<0.01). TG, ALT, AST of the group B were higher than those of the control group at the 24hr, 48hr and 72hr(P<0.01). While,TG, ALT, AST of the group C were lower than those of the group B at the 48hr and 72hr(P<0.01).3. The expression of p38MAPK protein of each observing time among the three groups had not difference. For 72hr,the expression of p-p38MAPK protein was upregulated in groups B, and as compared 24hr,48hr. (P<0.01),while,the expression of p-p38MAPK was significantly decresed in groups C,and compared with that in the group B(P<0.01).4. LPL-mRNA in group C had decreasing tendency time-dependently. The value of LPL(LPL/β-actin)of each observing time among the group C were different significantly (P<0.05). In group B, LPL/β-actin ratio was lower than those of the group C of each observing time(P<0.01). The mRNA level of LPL in control group had not significant change.5. LPL protein level in group C had decreasing tendency time-dependently. The LPL protein level of each observing time among the group C were different significantly (P<0.05). In group B, LPL protein level was lower than those of the group C of each observing time(P<0.01). The protein level of LPL in control group had not significant change.Conclusions:1. Adiponectin can improve the hepatisteatosis in vrtio in some degree.2. Adiponcetin can significantly decrease the p-p38mapk protein expression and the levels of TG,ALT and AST in steatositic hepatocytes, however,upregulated LPL expression in steatositic hepatocytes.Thus,these results suggested that there was a significant role of Adiponectin in the development of non-alcoholic fatty liver disease.3. p38MAPK and LPL are the important factors of which Adiponcetin have participated in the signal transmission of hepatosteatosis.