ABSTRACT
BACKGROUND: Stevia rebaudiana Bertoni leaves are well-known for their sweetness and have been used as a non-caloric sweetener in several countries. It has numerous therapeutic properties which have been proven safe and effective over hundreds of years. In the present study, we aimed to evaluate the possible antioxidant effects of stevia extracts and their role in regulating AMPK in type-1 diabetic rats. METHODS: Fifty male Sprague Dawely rats were divided into: (1) normal control (NC) group; normal rats receiving 0.5 ml normal saline, (2) DM group; diabetic rats receiving 0.5 ml normal saline, (3) DM + MSE group; DM rats receiving 200 mg/kg of methanolic extract of stevia, (4) DM + S group; DM rats receiving 2 mg/kg of pure stevioside, and (5) DM + CGA group; DM rats receiving 10 mg/kg of pure chlorogenic acid. Four weeks after treatment, AMPK activity, GLUT4 mRNA and oxidative stress markers were measured in frozen muscles. Also, fasting blood glucose in serum, insulin and HbA1c were measured at the end of experiment. RESULTS: DM caused a significant increase in serum fasting glucose, HbA1c and muscle MDA with significant reduction in serum insulin, muscle SOD, catalase, GPx, AMPK activity and GLUT4 expression (p < 0.05). Treatment with stevia extract, pure stevioside and chlorogenic acid caused significant improvements in the studied parameters (p < 0.05). CONCLUSIONS: We concluded that stevia extracts and derivatives may improve metabolic dysfunction in skel- etal muscles via upregulation of AMPK and GLUT4 and suppression of oxidative stress.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Antioxidants/pharmacology , Diabetes Mellitus, Type 1/metabolism , Muscle, Skeletal/drug effects , Oxidative Stress/drug effects , Plant Extracts/pharmacology , Stevia , Animals , Antioxidants/metabolism , Diabetes Mellitus, Type 1/drug therapy , Glucose Transporter Type 4/metabolism , Male , Muscle, Skeletal/metabolism , Phytotherapy , Plant Extracts/therapeutic use , Plant Leaves , Rats, Sprague-Dawley , Up-RegulationABSTRACT
The 4pi gamma-counting system is well suited for analysis of small environmental samples of low activity because it combines advantages of the low background and the high detection efficiency due to the 4pi solid angle. A new numerical simulation approach is proposed for the HPGe well-type detector geometry to calculate the full-energy peak and the total efficiencies, as well as to correct for the coincidence summing effect. This method depends on a calculation of the solid angle subtended by the source to the detector at the point of entrance, (Abbas, 2006a). The calculations are carried out for non-axial point and cylindrical sources inside the detector cavity. Attenuation of photons within the source itself (self-attenuation), the source container, the detector's end-cap and the detector's dead layer materials is also taken into account. In the Belgium Nuclear Research Center, low-activity aqueous solutions of (60)Co and (88)Y in small vials are routinely used to calibrate a gamma-ray p-type well HPGe detector in the 60-1836keV energy range. Efficiency values measured under such conditions are in good agreement with those obtained by the numerical simulation.
