RESUMEN
Objective To evaluate the effects of a traditional Chinese medicine Rubia cordifolia L.aqueous extract (RCAE) on body weight, fat mass and parameters of glucose and lipid metabolism in high fat diet (HFD)-induced obese rats and its mechanism.Methods pGL3-Enhancer-PPARγ2 (625 bp)-Luc plasmid, a luciferase reportergene expression plasmid containing PPARγ2 promoter was constructed and stably transfected 3T3-L1 preadipocytes were established.PPARγ2 promoter`s activities in these cells were detected after administration with different concentration (0.1 mg/L~1 000 mg/L) of RCAE or with 100 mg/L RCAE for different action time.PPARγ2 mRNA expression in human adipocytes were detected after administration with 100 mg/L RCAE.Meanwhile, HFD-induced obese rats were administrated with low or high dose RCAE to investigate the effects of RCAE on serum glucose, lipid and insulin levels, body weight, visceral fat mass and so on.Results 10 mg/L RCAE could increase luciferase expression in 3T3-L1 cells to 1.43 folds of that in control group (P<0.01) and it reached 3.24 folds of that in control group when the concentration of RCAE was 1000 mg/L (P<0.01).With the administration with 100 mg/L RCAE, the luciferase activity of 3T3-L1 cells peaked at 28 h where it was 2.72 folds of that in control group (P<0.01), and the expression of PPARγ2 mRNA in human adipocytes increased to 2.27 folds of that in control group (P<0.01).Compared with HFD group, low dose RCAE significantly reduced the fasting insulin level, HOMA-IR and visceral fat mass (P<0.05).Conclusions Low dose RCAE significantly reduces the visceral fat mass and ameliorates insulin resistance in HFD-induced obese rats.The potential mechanism may be explained by the stimulation of PPARγ2 promoter activities and the increased expression of PPARγ2 gene.
RESUMEN
Objective: To investigate the inhibitory effects of obestatin on proliferation and differentiation of 3T3-L1 preadipocytes. Methods: Obestatin (10-8 mmol/L, 10-9 mmul/L, 10-10 mmol/L, 10-11 mmol/L, and 10-12 mmol/L) and ghrelin (10-10 mmol/L) were used to treat 3T3-L1 preadipocytes. Cell proliferation was assessed by MTT assay and the results were compared with that of blank control group. The differentiation of 3T3-L1 preadipocytes (from day 1 to day 10) was interfered with obestatin or ghrelin (both at 10-10 mmol/L). Intracellular fat accumulation in differentiated adipocytes was determined by oil red O staining and the expression of PPAR-γ2 mRNA was detected by RT-PCR; the results were compared with that of control group (induced with routine inducer). Results: Compared with the blank control group, obestatin-treated groups (various concentrations of obestatin) had significantly less cells(P<0.05). Oil red O staining revealed that, compared with control group, the formation of lipid droplets was significantly decreased after 10 days' of treatment with 10-10 mmol/L obestatin (P<0.05). The expression of PPARγ2 gene increased with the progress of 3T3-L1 preadipocytes differentiation. PPAR-γ2 mRNA level in mature adipocytes of obestatin group was significantly lower than that in the cells of control group. The effect of ghrelin was contrary to that of obestatin. Conclusion: Obestatin can inhibit the proliferation and differentiation of 3T3-L1 preadipocyes.