Evaluation of plasma stability and pharmacokinetics of parthenolide in rats with LC-MS/MS analysis / 药学学报

Parthenolide is a sesquiterpene lactone derived from the plant feverfew (Tanacetum parthenium) that possesses multiple anti-inflammatory and anti-cancer properties. A specific, sensitive, accurate and precise LC-MS/MS method was developed and validated in the quantitative analysis of parthenolide in rat plasma. A liquid-liquid extraction method was used to separate the analyte and the internal standard (IS, costunolide) from plasma. A water-methanol mobile phase system was utilized in the gradient chromatographic separation. The calibration curve with good linearity (r2>0.99) was established between 2 and 128 ng·mL-1 with accuracy and precision within acceptable limits at different QC levels. High extraction recovery was achieved for both parthenolide (89.55%-95.79%) and IS (96.87%). Based on this LC-MS/MS method, the plasma stability and pharmacokinetics of parthenolide were assessed in rats. Parthenolide was proved to be very unstable in rat plasma, and was distributed and eliminated quickly in vivo, with a half-life less than 90 min. A high dose of parthenolide (80 mg·kg-1) resulted in a very low initial concentration (138.86±21.07 ng·mL-1). The systemic exposure of parthenolide (area under the curve) increased disproportionally from 40 mg·kg-1 dose group to 80 mg·kg-1 dose group. The present study may provide helpful information for the development of parthenolide as a drug candidate.

The synergistic effect of FGF-21 and insulin on regulating glucose metabolism and its mechanism / 药学学报

Previous studies proposed that the synergistic effect of fibroblast growth factor-21 (FGF-21) and insulin may be due to the improvement of insulin sensitivity by FGF-21. However, there is no experimental evidence to support this. This study was designed to elucidate the mechanism of synergistic effect of FGF-21 and insulin in the regulation of glucose metabolism. The synergistic effect of FGF-21 and insulin on regulating glucose metabolism was demonstrated by investigating the glucose absorption rate by insulin resistance HepG2 cell model and the blood glucose chances in type 2 diabetic db/db mice after treatments with different concentrations of FGF-21 or/and insulin; The synergistic metabolism was revealed through detecting GLUT1 and GLUT4 transcription levels in the liver by real-time PCR method. The experimental results showed that FGF-21 and insulin have a synergistic effect on the regulation of glucose metabolism. The results of real-time PCR showed that the effective dose of FGF-21 could up-regulate the transcription level of GLUT1 in a dose-dependent manner, but had no effect on the transcription level of GLUT4. Insulin (4 u) alone could up-regulate the transcription level of GLUT4, yet had no effect on that of GLUT1. Ineffective dose 0.1 mg kg(-1) FGF-21 alone could not change the transcription level of GLUT1 or GLUT4. However, when the ineffective dose 0.1 mg x kg(-1) FGF-21 was used in combination with insulin (4 u) significantly increased the transcription levels of both GLUT1 and GLUT4, the transcription level of GLUT1 was similar to that treated with 5 time concentration of FGF-21 alone; the transcription level of GLUT4 is higher than that treated with insulin (4 u) alone. In summary, in the presence of FGF-21, insulin increases the sensitivity of FGF-21 through enhancing GLUT1 transcription. Vice versa, FGF-21 increases the sensitivity of insulin by stimulating GLUT4 transcription in the presence of insulin. FGF-21 and insulin exert a synergistic effect on glucose metabolism through mutual sensitization.

FGF-21 protects H9c2 cardiomyoblasts against hydrogen peroxide-induced oxidative stress injury / 药学学报

Fibroblast growth factor-21 (FGF-21) is an important metabolism regulator, however, whether FGF-21 has effects on cardiovascular remains unclear. In this study, H2O2-induced injury in H9c2 cells was used as a cell model, the anti-apoptosis potential and mechanism of FGF-21 against oxidative injury were evaluated by MTT assay, flow cytometry assay and real-time PCR. The results showed that FGF-21 could increase the cell survival of H2O2-induced injury in H9c2 cells and prevent H9c2 cells from oxidative stress-induced apoptosis. Furthermore, FGF-21 can elevate SOD activity and regulate Bcl-2/Bax expression in H9c2 cells. The results suggest that FGF-21 have protective effect against the H2O2-induced apoptosis in H9c2 cells.

The long lasting effect of the murine fibroblast growth factor-21 on blood glucose control of diabetic animals / 药学学报

Insulin is the most common medicine used for diabetic patients, unfortunately, its effective time is short, even the long-acting insulin cannot obtain a satisfactory effect. Fibroblast growth factor (FGF)-21 is a recently discovered glucose mediator and expected to be a potential anti-diabetic drug that does not rely on insulin. In this study, db/db mice were used as the type 2 diabetic model to examine whether mFGF-21 has the long-term blood lowering effect on the animal model. The results showed that mFGF-21 could stably maintain the blood glucose at normal level for a long-term in a dose-dependent manner. Administration of mFGF-21 once a day with three doses (0.125, 0.25 and 0.5 mg x kg(-1)) could maintain blood glucose of the model animals at normal level for at least 24 h. Administration of mFGF-21 every two days with the same doses could maintain blood glucose of the model animals at normal level for at least 48 h, although it took longer time for blood glucose to reach to normal level depending on doses used (twenty injections for 0.125 mg x kg(-1) and 0.25 mg x kg(-1) doses, ten injections for 0.5 mg x kg(-1) dose). Surprisingly, the blood glucose of the treated model animals still maintained at normal level for 24 h after the experiment terminated. Glycosylated hemoglobin level of the animals treated with mFGF-21, which represented long-term glucose status, decreased significantly compared to the control group and the insulin group. The results suggest that FGF-21 has potential to become a long-acting and potent anti-diabetic drug.

Therapeutic effect of fibroblast growth factor 21 on hypertension induced by insulin resistance / 药学学报

This study is to evaluate the therapeutic effect of fibroblast growth factor 21 (FGF21) on hypertension induced by insulin resistance in rats and to provide mechanistic insights into its therapeutic effect. Male Sprague-Dawley (SD) rats were fed with high-fructose (10%) water to develop mild hypertensive models within 4 weeks, then randomized into 4 groups: model control, FGF21 0.25, 0.1 and 0.05 micromol x kg(-1) x d(-1) groups. Five age-matched normal SD rats administrated with saline were used as normal controls. The rats in each group were treated once a day for 4 weeks. Body weight was measured weekly, systolic blood pressure (SBP) was measured noninvasively using a tail-cuff method, insulin sensitivity was assessed using oral glucose tolerance test (OGTT) and HOMA-IR assay. At the end of the treatment, blood samples were collected, and blood glucose, serum cholesterol, serum triglyceride and serum insulin were measured. The results showed that blood pressure of the rats treated with different doses of FGF21 returned to normal levels [(122.2 +/- 3.5) mmHg, P < 0.01] after 4-week treatment, whereas, SBP of untreated (model control) rats maintained a high level [(142.5 +/- 4.5) mmHg] throughout the treatment. The observation of blood pressure in 24 h revealed that SBP of FGF21 treated-rats maintained at (130 +/- 4.5) mmHg vs. (143 +/- 5.5) mmHg for model control (P < 0.01). FGF21 treatment groups improved serum lipids obviously, total cholesterol (TC) and triglyceride (TG) levels decreased significantly to normal levels. The serum NO levels of three different doses FGF21 treatment group were significantly higher than that of the model control group [(7.32 +/- 0.11), (7.24 +/- 0.13), (6.94 +/- 0.08) vs. (6.56 +/- 0.19) micromol x L(-1), P < 0.01], and the degree of improvement showed obvious dose-dependent manner, indicating that FGF21 can significant increase serum NO in fructose-induced hypertension rat model and improve endothelial NO release function. The results of OGTT and HOMA-IR showed that insulin resistance state was significantly relieved in a dose-dependent manner. Thus, this study demonstrates that FGF21 significantly ameliorates blood pressure in fructose-induced hypertension model by relieving insulin resistance. This finding provides a theoretical support for clinical application of FGF21 as a novel therapeutics for treatment of essential hypertension.

Optimization and characterization of a novel FGF21 mutant / 药学学报

Fibroblast growth factor 21 (FGF21) is a member of FGF family. It has been demonstrated that FGF21 is an independent, safe and effective regulator of blood glucose levels in vivo. In order to improve the activity of FGF21, we exchanged the beta10-beta12 domain of the human FGF21 with that of the mouse FGF21 to construct a novel FGF21 gene (named hmFGF21), and then subcloned hmFGF21 gene into the SUMO expression vector to create pSUMO-hmFGF21 and transformed it into E. coli Rosetta for expression of the fusion protein SUMO-hmFGF21. Both in vitro and in vivo glucose regulation activity of hmFGF21 was evaluated. The SDS-PAGE result showed that compared with wild-type hFGF21, the soluble expression of hmFGF21 increased about 2-fold. HmFGF21 was more potent in stimulation of glucose uptake in HepG2 cells in vitro. The results of anti-diabetic effect on db/db mice demonstrated that hmFGF21 had better efficacy on controlling the blood glucose of the db/db diabetic animals than wild-type hFGF21. These results suggest that the biological properties of FGF21 are significantly improved by optimization.