Streptozotocin (STZ)-Induced Diabetic Mice

CWRU IACUC approved the animal protocols employed in this study. Diabetes was induced in 10-week-old male C57BL/6J mice (Jackson Laboratories, Bar Harbor, ME) by intraperitoneal injections of (STZ) streptozotocin (MPBio Solon, OH) at 60 mg/kg on five consecutive days. Diabetes was defined by 6 h fasted blood glucose concentrations greater than 275 mg/dl that were verified using glucose-dehydrogenase-based strips (Oak Tree Health Las Vegas, NV) 17 days after the last STZ injection (Day 22). Hyperglycemia was quantified by hemoglobin A1c levels at 8, 20, and 30 weeks post-diabetes using the Crystal Chem Mouse A1c kit (Elk Grove Village, IL). Insulin at 0–0.2U (Eli Lilly, Indianapolis, IN) was administered as-needed to maintain body-weight and prevent catabolic state. Body weight and hemoglobin A1c quantifications are shown in Figure 2 and Table 1.

Clinical Data of Non-Diabetic (ND) and Diabetic (DB) Mice.

Data are mean ± SD.

Clinical data of XMD8-92 treatment regimens. Quantifications of body weight (A) and hemoglobin A1c (B) in non-diabetic (ND) and STZ-diabetic (DB) C57BL/6 mice that received no (white), 5, 10, or 20 μM XMD8-92 treatments. Mice were subcutaneously injected once every other week (light grey), once a week (dark grey), or twice a week (black); 2 months after diabetes was confirmed (n = 3/group). Per a two-way ANOVA, wherein groups were nested as treated or diabetic, no significant differences in body weight (A) or Hemoglobin A1c (B) were found amongst the treated and untreated groups. Per an unpaired student’s t-test a statistically significant difference was calculated as p < 0.01 and denotated as * in body weight (A) and Hemoglobin A1c (B) between the non-diabetic controls and their experimental diabetic counterparts.

Retinal inflammation analyses were performed 2 months, oxidative stress analyses were performed 2 and 8 months, while vascular leakage and capillary degeneration were performed 8 months after diabetic conditions were confirmed. As previously described, these are the optimal time points for these analyses in this murine model (Kern et al., 2010; Veenstra et al., 2015; Lindstrom et al., 2019; Zapadka et al., 2020).