Objective: To investigate the expression of peroxisome proliferator-activated receptor-coactivator-1 (PGC-1) in the diabetic liver and the role thereof in the development of hyperglycemia and diabetes.
Methods: Sixteen Wistar rats were randomly divided into 2 groups: Group A (n=11), undergoing intraperitoneal injection of streptozocin (STZ) to establish diabetic rat models, and Group B (n=6) undergoing injection of STZ and subcutaneous injection of insulin. Another 9 rats were used as normal controls (Group C). Then blood samples were collected from the abdominal aortas to examine the fasting blood glucose (FBG), serum total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C). Their livers were taken out. RT-PCR and Western blotting were used to examine the PGC-1 mRNA and protein expression.
Results: The FBS and TC levels of Group A were both significantly higher than those of Group C (P < 0.01, P < 0.05). The PGC-1 protein expression level in liver of Group A was 2.47 times that of the Group C (P < 0.01) and 1.57 times that of Group B (P < 0.05). The PGC-1 mRNA expression level in the liver of Group A was (165.6 +/- 41.6), significantly higher than that of Group B [(121.6 +/- 25.4), P < 0.05] and that of Group C [(109.15 +/- 21.8), P < 0.01].
Conclusion: The PBC-1 protein and mRNA expression levels in the liver of diabetic animals are significantly higher than those of the normal livers, and can be reversed by insulin therapy. High PGC-1 expression in the diabetic liver may be related to the hyperglycemia in type 2 diabetes.