Effect of electroacupuncture on liver Akt/FoxO1 signaling pathway in rats with diabetic fatty / 中国针灸

OBJECTIVE@#To observe the effect of electroacupuncture (EA) on liver protein kinase B (Akt)/forkhead box transcription factor 1 (FoxO1) signaling pathway in Zucker diabetic fatty (ZDF) rats, and to explore the possible mechanism of EA on improving liver insulin resistance of type 2 diabetes mellitus.@*METHODS@#Twelve male 2-month-old ZDF rats were fed with high-fat diet for 4 weeks to establish diabetes model. After modeling, the rats were randomly divided into a model group and an EA group, with 6 rats in each group. In addition, six male Zucker lean (ZL) rats were used as the blank group. The rats in the EA group were treated with EA at bilateral "Zusanli" (ST 36), "Sanyinjiao" (SP 6), "Weiwanxiashu" (EX-B 3), and "Pishu" (BL 20). The ipsilateral "Zusanli" (ST 36) and "Weiwanxiashu" (EX-B 3) were connected to EA device, continuous wave, frequency of 15 Hz, 20 min each time, once a day, six times a week, for a total of 4 weeks. The fasting blood glucose (FBG) in each group was compared before modeling, before intervention and after intervention; the serum levels of insulin (INS) and C-peptide were measured by radioimmunoassay method, and the insulin resistance index (HOMA-IR) was calculated; HE staining method was used to observe the liver tissue morphology; Western blot method was used to detect the protein expression of Akt, FoxO1 and phosphoenolpyruvate carboxykinase (PEPCK) in the liver.@*RESULTS@#Before intervention, compared with the blank group, FBG was increased in the model group and the EA group (P<0.01); after intervention, compared with the model group, FBG in the EA group was decreased (P<0.01). Compared with the blank group, the serum levels of INS and C-peptide, HOMA-IR, and the protein expression of hepatic FoxO1 and PEPCK were increased (P<0.01), while the protein expression of hepatic Akt was decreased (P<0.01) in the model group. Compared with the model group, the serum levels of INS and C-peptide, HOMA-IR, and the protein expression of hepatic FoxO1 and PEPCK were decreased (P<0.01), while the protein expression of hepatic Akt was increased (P<0.01) in the EA group. In the model group, the hepatocytes were structurally disordered and randomly arranged, with a large number of lipid vacuoles in the cytoplasm. In the EA group, the morphology of hepatocytes tended to be normal and lipid vacuoles were decreased.@*CONCLUSION@#EA could reduce FBG and HOMA-IR in ZDF rats, improve liver insulin resistance, which may be related to regulating Akt/FoxO1 signaling pathway.

Berberine Induces Cell Apoptosis through Cytochrome C/Apoptotic Protease-Activating Factor 1/Caspase-3 and Apoptosis Inducing Factor Pathway in Mouse Insulinoma Cells / 中国结合医学杂志

OBJECTIVE@#To investigate apoptotic effects of berberine, a significant alkaloids component existing in Rhizoma coptidis, and its possible acting mechanism in insulinoma cells.@*METHODS@#Different concentrations of berberine were used to treat mouse insulinoma (MIN6) cells for various period of time. The viability and apoptosis of the cells were analyzed using methylthiazolyldiphenvl-tetrazolium bromide assay, flow cytometry and enzyme-linked immuno sorbent assay. Changes in the relating pro- and anti-apoptosis proteins were detected by western-blotting.@*RESULTS@#The half-maximal inhibitory concentration (IC) of berberine was 5.7 μmol/L on MIN6 cells viability for 16 h. Berberine caused a 20% reduction (P<0.05) in cell number after only 4-h incubation; which reached 50% after 24 h (P<0.01). Berberine treatment for 16 h significantly increased the level of DNA fragmentation. The flow cytometry showed the apoptotic rate increased 2.9- and 4.6-fold after treating with berberine (5 μmol/L) for 8 and 16 h, while 3- and 8.7-fold after 10 μmol/L treatment for 8 and 16 h (P<0.01). Berberine treatment dramatically elevated the expression ratio of Bax to Bcl-2. Meanwhile, berberine notably increased the apoptosis-inducing factors and cytochrome C transforming from the mitochondria to the cytoplasm. Apoptotic protease-activating factor 1 (Apaf-1) was subsequently activated after cytochrome C release. Furthermore, caspase-3 and poly adenosine diphosphate-ribose polymerase were also activated to trigger apoptosis cascade.@*CONCLUSION@#High concentration (5 and 10 μmol/L) of berberine could induce the apoptosis of MIN6 cells through cytochrome C/Apaf-1/caspase-3 and apoptosis inducing factor (AIF) pathway.