Alphatrak 2 blood glucose monitoring system

Experimental feeding of offspring began at weaning on PND 21. Mice were housed by sex, 3–6 per cage depending on litter size, and given ad libitum access to food and water. Offspring diet was either low-fat diet (LFD – 10% kCal fat; Research Diets D12450H) or a standard high-fat diet (HFD – 45% kCal fat; Research Diets D12451). Body weight and food intake (per cage food intake) were recorded weekly for 25 weeks followed by body composition measurements using an EchoMRI 3-in-1 Body Composition Analyzer (Echo Medical Systems, Houston, TX, USA) and calorimetric and activity measurements (48 h run) via Columbus Instruments’ Comprehensive Lab Animal Monitoring System (Columbus Instruments, Inc., Columbus, OH, USA). A glucose tolerance test (GTT), following a 5 h fast, was administered via intraperitoneal (ip) injection of 2 g/kg glucose in 0.9% saline solution. Blood glucose (BG) from tail blood was measured with an AlphaTrak 2 Blood Glucose Monitoring System (Abbott Laboratories, Abbott Park, IL, USA) pre-injection and 15, 30, 60, 90, 120, and 180-min post-injection. An insulin tolerance test (ITT) following a 4 h fast involved an injection of 0.75 U/kg insulin (Humulin R, Lilly, Indianapolis, IN, USA) in 0.9% saline solution and followed the same BG measurement scheme as GTT. Mice were given 4 days of rest each between CLAMS, GTT, and ITT.

Animals were observed daily while on study to monitor for adverse effects of diabetes. As diabetic mice typically become polyuric, polydipsic, and/or polyphagic, cages were changed and additional food and water provided more frequently as needed. Additional food pellets were placed on the cage floor to ensure access for obese diabetic mice. During the 4 weeks on study, mice were individually weighed twice weekly. Non-fasted BG measurements were performed during the first 3 h of the light cycle to minimize effects of diurnal variation. Using a restraint device designed for tail access (Tailveiner Restrainer, Brainstree Scientific, Inc, Braintree, MA), blood was collected from the lateral tail vein. BG was measured using a handheld glucometer (AlphaTRAK 2 Blood Glucose Monitoring System, Abbott Animal Health, Zoetis, Florham Park, NJ) with a testing range of 20–750 mg/dL; several BG measurements for diabetic mice were above the testing range and were recorded as 750 mg/dL. Mice with blood glucose consistently >250 mg/dL were considered diabetic.