[The effects of arecoline on the lipid metabolism of 3T3-L1 adipocytes].

OBJECTIVE: To observe the effects of arecoline on lipid metabolism in 3T3-L1 adipocytes and explore its possible mechanisms. METHODS: 3T3-L1 pre-adipocytes were induced into adipocytes with the classic "cocktail" method, subsequently, adipocytes were treated with arecoline at the concentrations of 0, 25, 50 and 100 µmol/L for 72 hours. After 72 hours, cell vability was measured with MTT method, lipid droplet accumulation in the cytoplasm was observed with oil red O staining, the protein expression of fatty acid synthase (FAS), adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) were detected by Western blot assay. RESULTS: There were a large number of lipid droplets in the cytoplasm in the differentiated 3T3-L1 adipocytes. MTT results showed that 0~100 µmol/L arecoline had no significant effect on cell vability; oil red O staining found arecoline reduced lipid amount in 3T3-L1 adipocytes; Western blot results showed that compared with 0 µmol/L arecoline group (the control group), arecoline significantly reduced the protein level of FAS and increased the protein levels of ATGL and HSL, and 50 µmol/L arecoline group was the most significant. CONCLUSIONS: Arecoline significantly increased lipolysis of 3T3-L1 adipocyte, which might be associated with decreased the FAS expression of key enzyme of lipid synthesis and increased the ATGL and HSL expression of key enzyme of adipolysis.

[The effects of dihydromyricetin on cognitive dysfunction in type 2 diabetes mice].

OBJECTIVE: To observe the effects of dihydromyricetin(DHM) on cognitive dysfunction and expression of brain derived neurotrophic factor(BDNF) protein in hippocampus of type 2 diabetic mice(T2DM). METHODS: Forty C57BL/6J mice were randomly divided into two groups, normal control group (n=8):normal diet feeding; T2DM model group (n=32):high-glucose and high-fat combined with 100 mg/kg streptozocin(STZ) treatment (five mice died during modeling and three failed). Twenty-four diabetic mice were modeled successfully and divided into three groups (T2DM group, T2DM+L-DHM group and T2DM+H-DHM group). Three groups mice were fed with high-glucose and high-fat diet, and treated with equal volume of normal saline, 125 mg/(kg·d) DHM or 250 mg/(kg·d) DHM for 16 weeks respectively. The control mice were fed with normal diet and treated with equal volume of saline (once a day, gavage) for 16 weeks. After 16 weeks, the body weight and fasting blood glucose were measured, intraperitoneal glucose tolerance test and related behavioral experiment were performed. Finally, the expression of BDNF protein in hippocampus of mice was detected by Western blot. RESULTS: The model of type 2 diabetes mellitus was established successfully with high-glucose and high-fat combined with 100 mg/kg STZ. After 16 weeks, the body weight of T2DM group was significantly decreased, the fasting blood glucose was significantly increased and the glucose tolerance was significantly abnormal compared with the normal control group. Compared with T2DM group, the body weight of T2DM+DHM groups mice was increased, while the levels of fasting blood glucose were decreased. And H-DHM could significantly improve the abnormal glucose tolerance of T2DM mice. Behavior test results showed that the ability of learning and memory of T2DM mice was significant decreased compared with control group, but these phenomena were improved in T2DM+DHM groups mice, and T2DM+H-DHM group was more obvious. Western blot analysis showed that the expression of BDNF protein in hippocampus of T2DM group was significantly lower than that of control group, while T2DM+DHM group was significant increased compared with T2DM mice. CONCLUSIONS: Dihydromyricetin can improve the cognitive dysfunction in type 2 diabetic mice. The mechanism may be through hypoglycemic effect and activation of BDNF protein expression in hippocampus.

[Effect of arecoline on proliferation and apoptosis of MCF-7 human breast cancer cells].

OBJECTIVE: To observe the effects of arecoline on proliferation and apoptosis of MCF-7 human breast cancer cells and to ex-plore its possible mechanism. METHODS: Human breast cancer MCF-7 cells were treated with arecoline at the concentrations of 0,10,30,50, 100,300,500µmol/L, the cell proliferation were detected by MTT assay, cell apoptosis were analyzed by Hoechst 33342 staining and flow cy-tometry, the protein expression of Bax,Bcl-2 and P53 were detected by Western blot. RESULTS: Low concentration(0,10,30, 50 µmol/L) arecoline had no effect on the proliferation and apoptosis of MCF-7. However, high concentration(100,300,500µmol/L) arecoline inhibited proliferation and induced apoptosis of MCF-7 cells in a concentration-dependent manner, arecoline also significantly increased P53 and Bax protein expression and decreased Bcl-2 protein expression. CONCLUSIONS: High concentration arecoline inhibited the proliferation and induced the apoptosis of MCF-7 cells, the mechanism was probably corrected with increasing P53 and Bax protein expression and decreasing Bcl-2 pro-tein expression.

[The role of arecoline on hepatic insulin resistance in type 2 diabetes rats].

OBJECTIVE: To explore the effects of arecoline on hepatic insulin resistance in type 2 diabetes rats and to elucidate its possible mechanism. METHODS: Forty five Wistar rats were fed with high fructose diet for 12 weeks to induce type 2 diabetic rat model. rats were randomly divided into 5 groups (n = 8): control group, model group and model group were treated with different dose (0, 0.5, 1, 5 mg/kg) of arecoline. After 4 weeks, the fasting blood glucose, blood lipid and insulin level measured , mRNA expression of liver constitutive androstane receptor (CAR), pregnane X receptor (PXR), glucose-6-phosphatase (G6Pase), phosphoenolpyruvate carboxykinase (PEPCK), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were detected by reverse transcription polymerase chain reaction (RT-PCR), the protein expression of p-AKT and glucose transporter4 (GLUT4) were detected by Western blot. RESULTS: 1.5 mg/kg arecoline could significantly decrease the level of fasting blood glucose, blood lipid, blood insulin level and liver G6Pase, PEPCK, IL-6, TNF-alpha mRNA level in type 2 diabetes rats. 1.5 mg/kg arecoline also could significantly increase CAR, PXR mRNA level and p-AKT and GLUT4 protein expression. CONCLUSION: Arecoline improved hepatic insulin resistance in type 2 diabetes rats by increasing the mRNA levels of CAR and PXR leading to the creased glucose metabolism and inflammation related genes expression.

[miRNA expression change of differentiation of mice marrow mesenchymal stem cells into adipocytes].

OBJECTIVE: To explore miRNA expression change of differentiation of mice marrow mesenchymal stem cells (MSCs) into adipocytes, which lay the foundation for further studies on molecular mechanism of miRNA regulating the differentiation of MSCs into adipocytes. METHODS: C57BL/6 mice MSCs were isolated, cultured through the whole bone marrow method, amplified by the differential adherent method. Cell growth was observed by morphology and the expression of superficial antigen CD29, CD44, CD34 were detected through immunohistochemistry. MSCs was induced to differentiation into adipocytes with adipocyte differentiation medium, and adipogenic differentiation of MSCs was analyzed by oil Red O staining. MicroRNA microarray was used to investigate the differentially expressed miRNAs in MSCs and adipocytes. RESULTS: (1) The fifth passage of MSCs had high purity under an inverted m icroscope. Immunohistochemistry staining showed that CD29, CD44 were positive and CD34 was negative in more than 90% MSCs. There were a large number of lipid droplets in cytoplasm after MSCs were induced with adipocyte differentiation medium, Oil O staining was positive. (2) The microarray experiment showed that 75 differentially expressed miRNAs were obtained in adipocytes compared with MSCs, 20 up-regulated and 55 down-regulated miRNAs were observed among them. CONCLUSION: There was a expression change of miRNA of differentiation of MSCs into adipocytes, some miRNAs might play important roles in MSCs adipogenic differentiation.