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Modeling and Evaluation of Murine Diabetic Cardiomyopathy Model
Published on: November 29, 2024
Young NOD mice show increased diabetes sensitivity to low doses of streptozotocin
Shiva Reddy1, Mike Chang, Elizabeth Robinson
1School of Biological Sciences, University of Auckland, Auckland, New Zealand. s.reddy@auckland.ac.nz
Abstract:
In type 1 diabetes, environmentally induced early-limited beta cell damage may pre-empt the subsequent immune-mediated beta cell destruction. Low doses of streptozotocin (Stz), given early to diabetes-prone mice, may cause limited beta cell destruction during the early phase and precipitate diabetes. Here, we aimed to see if young NOD mice are more diabetes-sensitive to various multiple low doses of Stz than non-diabetes-prone mice. We also determined the molecular pathology of islets following administration of the diabetogen. Female NOD and CD-1 mice received 5 daily doses of Stz at day 21 (20, 30, and 40 mg/kg body weight; 18 mice per group) or diluent, and diabetes was monitored. Pancreas were studied histochemically and immunohistochemically at various time points after Stz administration. Following administration of Stz, NOD mice showed a much earlier onset and increased diabetes rate, at all three doses, than CD-1 mice. By day 80, the final diabetes rates following the 40, 30, and 20 mg dose in NOD mice were 95%, 85%, and 33%, respectively, compared with 33%, 28%, and 5.5%, respectively, in CD-1 mice. However, following the 20 mg dose, only 2 of the 12 remaining NOD mice developed the disease between 90 and 250 days compared with 19 of 24 NOD mice that did not receive Stz at day 21. Stz-administered NOD and CD-1 mice showed an initial loss of beta cells, with redistribution of islet endocrine cells, early macrophage infiltration, and increasing insulitis.
Insights
Young NOD mice are more susceptible to streptozotocin (Stz)-induced diabetes than CD-1 mice. Early low-dose Stz administration accelerates diabetes onset and increases incidence in NOD mice, mimicking type 1 diabetes progression.
Area of Science:
- Immunology
- Endocrinology
- Diabetes Research
Background:
- Type 1 diabetes involves immune-mediated beta cell destruction.
- Early environmental factors may trigger beta cell damage, preceding immune attack.
- Streptozotocin (Stz) can induce diabetes in animal models.
Purpose of the Study:
- To assess the diabetes sensitivity of young NOD mice to multiple low doses of Stz compared to non-diabetes-prone mice.
- To investigate the molecular pathology of islets after Stz administration in NOD mice.
Main Methods:
- Female NOD and CD-1 mice received daily low doses of Stz (20, 30, 40 mg/kg) starting at day 21.
- Diabetes incidence and onset were monitored.
- Pancreatic islets were analyzed histochemically and immunohistochemically.
Main Results:
- NOD mice exhibited significantly earlier onset and higher diabetes rates across all Stz doses compared to CD-1 mice.
- At day 80, diabetes rates in NOD mice were 95% (40 mg/kg), 85% (30 mg/kg), and 33% (20 mg/kg), versus 33%, 28%, and 5.5% in CD-1 mice, respectively.
- Stz-treated NOD and CD-1 mice showed beta cell loss, islet endocrine cell redistribution, early macrophage infiltration, and increased insulitis.
Conclusions:
- Young NOD mice are highly sensitive to low-dose Stz, developing diabetes more readily than CD-1 mice.
- Early Stz administration in NOD mice accelerates diabetes development and alters islet pathology, providing a model for type 1 diabetes research.
- The findings suggest that early beta cell damage can precipitate autoimmune diabetes in susceptible individuals.
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