ABSTRACT
This study investigated the effects and molecular mechanisms of genistein in improving insulin resistance induced by free fatty acids (FFAs) in HepG2 hepatocytes.A model of insulin resistance in HepG2 cells was established by adding palmitic acid (0.5 mmol/L) to the culture medium and the cells were treated by genistein.Glucose consumption of HepG2 cells was determined by glucose oxidase method.The levels of c-jun N-terminal kinase (JNK) phosphorylation,insulin receptor substrate-1 (IRS-1) Ser307 phosphorylation,JNK,IRS-1,phosphatidylinositol-3-kinase p85 (PI-3K p85) and glucose transporter 1 (GLUT1) proteins were detected by Western blotting.The results showed that after the treatment with palmitic acid for 24 h,the insulin-stimulated glucose transport in HepG2 cells was inhibited,and the glucose consumption was substantially reduced.Meanwhile,the expressions of IRS-1,PI-3K p85 protein and GLUT1 were obviously reduced,while the levels of JNK phosphorylation and IRS-1 Ser307 phosphorylation and the expression of JNK protein were significantly increased,as compared with cells of normal control.However,the aforementioned indices,which indicated the existence of insulin resistance,were reversed by genistein at 1-4 μmol/L in a dose-dependent manner.It was concluded that insulin resistance induced by FFAs in HepG2 hepatocytes could be improved by genistein.Genistein might reverse FFAs-induced insulin resistance in HepG2 cells by targeting JNK.
ABSTRACT
The effects of Cinnamon granules on pharmacokinetics of berberine in Rhizoma Coptidis granules in healthy male volunteers,and the compatibility mechanism of Jiao-Tai-Wan (JTW) composed of Rhizoma Coptidis granules and Cinnamon granules were investigated.The concentration of berberine in plasma of healthy male volunteers was determined directly by high performance liquid chromatography (HPLC) after an oral administration of Rhizoma Coptidis granules alone or combined with Cinnamon granules (JTW).The plasma concentration-time curves of berberine were plotted.The data were analyzed with Drug and Statistics (DAS) 2.0 pharmacokinetic program (Chinese Pharmacology Society)to obtain the main pharmacokinetic parameters.The results showed that the plasma concentration-time curve of berberine was described by a two-compartment model.The Cmax,Tmax,t1/2 and CLz/F of berberine in Rhizoma Coptidis granules were 360.883 μg/L,2.0 h,3.882 h,119.320 L·h-1·kg-1 respectively,and those of berberine in JTW were 396.124 μg/L,1.5 h,4.727 h,57.709 L·h-1·kg-1 respectively.It was suggested that Rhizoma Coptidis granules combined with Cinnamon granules could increase the plasma concentration of berberine,promote berberine absorption and lengthen the detention time of berberine in healthy male volunteers.
ABSTRACT
In vivo imaging system(IVIS)is a new and rapidly expanding technology,which has a wide range of applications in life science such as cell tracing.By counting the number of photons emitted from a specimen,IVIS can quantify biological events such as tumor growth.We used B16F10-luc-G5 tumor cells and 20 Babl/C mice injected subcutaneously with B16F10-luc-G5 tumor cells(1×106 in 100 μL)to develop a method to quantitatively analyze cells traced by IVIS in vitro and in vivo,respectively.The results showed a strong correlation between the number of tumor cells and the intensity of bioluminescence signal(R2=0.99)under different exposure conditions in in vitro assay.The results derived from the in vivo experiments showed that tumor luminescence was observed in all mice by IVIS at all days,and there was significant difference(P<0.01)between every two days from day 3 to day 14.Moreover,tumor dynamic morphology could be monitored by IVIS when it was invisible.There was a strong correlation between tumor volume and bioluminescence signal(R2=0.97)by IVIS.In summary,we demonstrated a way to accurately carry out the quantitative analysis of cells using IVIS both in vitro and in vivo.The data indicate that IVIS can be used as an effective and quantitative method for cell tracing both in vitro and in vivo.
ABSTRACT
The effects of berberine on the expression of hepatocyte nuclear factor-4α (HNF-4α) in liver of rats with fructose-induced insulin resistance and the molecular mechanism of berberine preventing insulin resistance were investigated. The experimental animals were divided into two groups of 16 animals each. The control group received a control routine diet containing 60% carbohydrate, and the study group a high-fructose diet containing 60% fructose as the sole source of carbohydrate. At the end of 6 weeks these were each subdivided into two groups. One was administered with berberine [187.5mg/(kg·d) in 5g/L carboxymethyl cellulosel] by intragastric intubation and the other group was treated with a vehicle (5g/L carboxymethyl cellulose). The rats were fed on the same dietary regimen for the next 4 weeks. After the experimental period of 10 weeks, plasma glucose, insulin and triglyceride levels were measured. HOMA insulin resistance index (HOMA-IR) was assayed. Immunohistochemistry, semiquantitative RT-PCR and western blot were used to detect the expression of HNF-4α in liver. Compared with control diet, fructose feeding induced hyperinsulinemia, HOMA-IR and increased triglyceride (all P<0.01). Berberine prevented the rise in plasma insulin (P<0.01), HOMA-IR (P<0.01) and triglyceride (P<0.05) in the fructose-fed rats. No change in plasma glucose was seen among these groups. The mRNA and protein expression of HNF-4α was decreased in the fructose-fed rats, but berberine could promote its expression. It was concluded that berberine could prevent fructose-induced insulin resistance in rats possibly by promoting the expression HNF-4α in liver.