ABSTRACT
BACKGROUND AND RATIONALE: Non-alcoholic hepatic steatosis refers to the accumulation of triglycerides in the liver in the absence of alcohol consumption. Granulocyte colony-stimulating factor (G-CSF) has been reported to be an effective treatment for a variety of liver diseases. We examined the possible therapeutic effects of G-CSF on non-alcoholic hepatic steatosis in rats. MATERIAL AND METHODS: Thirty-week-old Otsuka Long Evans Tokushima Fatty (OLETF) rats received water containing 30% sucrose for 8 weeks to promote the development of non-alcoholic hepatic steatosis. After development of the model, the rats were injected with G-CSF (100 µg/kg/day) or saline for 5 days. Four weeks after this treatment, serum levels of glucose, total cholesterol (TC), triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and free fatty acids (FFA) were measured. Histology was examined by hematoxylin and eosin (H-E) and periodic acid Schiff (PAS) staining, and levels of expression of hepatic lipogenic enzymes were determined by RT-PCR. RESULTS: The G-CSF-treated rats displayed significantly fewer lipid droplets than the saline-treated rats (P < 0.01), and their levels of sterol regulatory element-binding protein (SREBP)-1c, fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) mRNAs were also lower (P < 0.01), as were their liver weight and serum levels of TG and FFA (P < 0.05). CONCLUSION: Our results indicate that G-CSF ameliorated non-alcoholic hepatic steatosis in the OLETF rat, and this therapeutic effect involved a reduction of SREBP-1c expression. Therefore, G-CSF deserves further study as a potential treatment for non-alcoholic hepatic steatosis.
Subject(s)
Fatty Liver/drug therapy , Granulocyte Colony-Stimulating Factor/therapeutic use , Acetyl-CoA Carboxylase/genetics , Acetyl-CoA Carboxylase/metabolism , Alanine Transaminase/blood , Animals , Aspartate Aminotransferases/blood , Blood Glucose/drug effects , Cholesterol/blood , Fatty Acid Synthases/genetics , Fatty Acid Synthases/metabolism , Fatty Acids, Nonesterified/blood , Fatty Liver/blood , Fatty Liver/pathology , Lipogenesis/drug effects , Lipogenesis/genetics , Liver/drug effects , Liver/metabolism , Liver/pathology , Male , Non-alcoholic Fatty Liver Disease , Organ Size/drug effects , RNA, Messenger/analysis , Rats , Rats, Inbred OLETF , Real-Time Polymerase Chain Reaction , Sterol Regulatory Element Binding Protein 1/genetics , Sterol Regulatory Element Binding Protein 1/metabolism , Triglycerides/bloodABSTRACT
Human and experimental diabetes mellitus extensively alters lipid metabolism. The eSS is a rat strain that develops a spontaneous diabetes of slow evolution, resembling the non-insulin-dependent diabetes mellitus of young people. We report here disturbances in lipid metabolism of 5-month old eSS rats compared to age-matched alpha-controls. Normal plasmatic glucose levels were found in the fasted state, whereas a diabetic curve was evident for eSS rats after glucose load. Triglyceride content was elevated in plasma and in liver microsomal preparations of eSS animals, when compared to the controls. The diabetic strain revealed a significant fall in the amount of linoleic acid in liver and kidney microsomes and in erythrocyte membranes. In liver, an increase in 22:6 (n-3) was also noted. A depression in the content of linoleic acid as well as an enhancement of docosahexaenoic acid were detected in phosphatidylcholine and phosphatidylethanolamine fractions from liver microsomes of eSS rats. The fatty acid pattern of eSS rat testis showed a raise in the relative percentage of arachidonic and a decrease in 22:5 (n-6), 22:5 (n-3) and 22:6 (n-3) acids compared to their controls. Diabetic rats exhibited a significant increase in microsomal cholesterol content and cholesterol/phospholipid ratio in liver and testis. In the latter tissue, higher values of fluorescence anisotropy were also observed. The current observations indicate that in early stages of the diabetes onset, when eSS rats are still normoglycemic, severe alterations of lipid metabolism may contribute to the establishment and progression of the diabetic syndrome.