Sprague-Dawley Rat Diabetes Model

Sprague-Dawley male rats (Crl: SD) were originally sourced from Charles River Labs Inc. and bred at Rutgers University. The rats were 6 to 23 weeks old at the beginning of the study. Two animals were housed per cage, at 20–22°C with a 12-hour light/dark cycle. Filtered tap water and rat chow pellets were available ad libitum. Soft gel food (25–50 g/dish/day/rat, Diet Gel 76A) was provided to rats exhibiting severe dehydration or otherwise recommended for extra care by the Rutgers' veterinarian. Cage bedding was changed frequently following the induction of diabetes due to polyuria. Animals were maintained without antihyperglycemic treatment (insulin). A total of 153 rats were included in this study; 130 rats received STZ injection to induce diabetes, and the remainder were injected with 0.01 M sodium citrate as nondiabetic controls (sham). All injections were 2 ml/kg i.v. The STZ-injected rats were grouped by body weight; group 1 included 67 rats 220–400 g (6–11 weeks old); group 2 included 29 rats 401–500 g (12–17 weeks old); and group 3 included 34 rats 501–600 g (18–23 weeks old). STZ injection regimens are described in Table 1.
About 100 μl blood was collected weekly or biweekly during the observation period and used to measure blood glucose and lipid levels, and 100 μl plasma was collected (in K2-EDTA) and stored at −80°C for analysis of cytokine and metabolic hormone levels as shown in the results.
All animal care and experimental procedures were performed in an AAALAC-accredited facility under a Rutgers IACUC-approved animal care and use protocol in accordance with the Guide for the Care and Use of Laboratory Animal.