Blood glucose monitoring system

Specific pathogen-free Sprague-Dawley (SD) male rats (180–200 g, 6 weeks old) were provided by the Experimental Animal Center of the Three Gorges University School of Medicine. Animals were given 12 hours of light-darkness cycle at a relative ambient temperature (20 ± 2°C) and a relative air humidity (55 ± 10%) and allowed free access to water and standard rodent food. After one week of adaptation to the environment, the rats were randomly divided into 3 groups: vehicle control group (NC group, n=20), diabetic nephropathy group (DN group, n=20), DN rat treated with Calcitriol group (DN+VD group, n=20). Streptozotocin (STZ) (Sigma, USA) was dissolved in 0.1M citrate buffer (pH 4.4) at a concentration of 4 mg/mL, and a single rapid injection into the intraperitoneal at a dose of 60 mg/kg. The control group was injected an equal amount of 0.1M citrate buffer. Three days later, the randomly rat’s tail vein blood glucose was measured ≥16.7mmol/L considered as diabetes rats, and then which were monitored every two weeks using a blood glucose monitoring system (Bayer). Calcitriol (Roche Company, USA) was dissolved in edible peanut oil at a concentration of 0.04μg/mL and was delivered by oral gavage at a daily dose 0.1 μg/kg after starting at 3 days after STZ injection until sacrifice. The DN group and the control group received an equal amount of edible peanut oil.

Voglibose (>98.0%) was purchased from Tokyo Chemical Industries (Tokyo, Japan). Erythromycin, oxytetracycline hydrochloride, cefadroxil, 4-nitrophenyl β-D-glucopyranoside, 4-nitrophenyl β-D-glucuronide, 4-nitrophenyl sulfate, soluble starch, ammonium acetate, streptozotocin, and telmisartan, the internal standard (IS), were purchased from Sigma-Aldrich (St. Louis, MO, USA). High-performance liquid chromatography (HPLC)-grade acetonitrile was purchased from J. T. Bakers (Central Valley, PA, USA). An anaerobe gas generating system was purchased from Becton, Dickinson and Company (Sparks, MD, USA). A blood glucose monitoring system was purchased from Bayer Contour TS (Mishawaka, IN, USA). Potassium phosphate monobasic and potassium phosphate dibasic were purchased from Duksan (Seoul, Korea). All other chemicals were of analytical grades and used as received.