Effect Of Berberine On The Ratio Of High-Molecular Weight (HMW)Adiponectin To Total Adiponectin Concentrations And Adiponectin Receptors Expressions In High-Fat Fed Rats

Aims/hypothesisBerberine has been shown to have effects on improving insulin resistance. But the exact mechanism of it is unknown. Recently reported that berberine could promote the ratio of HMW to total adiponectin in3T3-L1adipocytes. So, whether the mechanism of improving insulin resistance relevant to the ratio of HMW. We evaluated the ratio of HMW and adiponectin receptors in high-fat diet rats with or without berberine treatment.MethodsWe studied40Wistar male rats, randomly assigned them into NF, HF, HF+LBBR and HF+HBBR four groups. The12weeks high-fat diet was apply for them except for NF group. At end of8weeks HF+LBBR and HF+HBBR group were treated with different dose of berberine while other treated with vehicle. Glucose tolerance test (GTT) and insulin tolerance test (ITT) were carried out in all the groups at the end of study period. Then, blood samples, visceral fat, skeletal muscle and liver tissue were removed for detecting the metabolic indices, the ratio of HMW and adiponectin receptors expression.ResultsBerberine treatment can promote the ratio of HMW in serum, visceral fat, skeletal muscle and liver tissue of high-fat diet rats. We also find that berberine can increase adipoRl and adipoR2expression in skeletal muscle and liver cell, respectively. In addition berberine treatment was associated with lower body weight, free fatty acid, fasting insulin levels as well as improve insulin resistance in HF+LBBR and HF+HBBR group than in the HF group. Pearson correlation analysis showed that the ratio of HMW negatively correlated with HOMA-IR. Further partial correlation analysis showed the HMW ratio in visceral fat had indeed negative correlation with HOMA-IR (Partial r=-0.45, P=0.007).Conclusions/interpretationWe find that the increase of the ratio of HMW and adipoRl, adipoR2expression were showed close correlation with the improving of insulin resistance in high-fat diet rats with berberine treatment. All of this suggests that berberine improve insulin resistance may be through promote the ratio of HMW and enhance the expression of adiponectin receptors.