InnoSer standardly works according to regulatory guidelines to include both male and female rodents in preclinical studies to gain insight into sex differences in disease manifestation and response to therapies. However, the NOD mouse model shows a marked and well-documented sex difference in spontaneous diabetes incidence across scientific literature (Rosmalen et al., 2001). Accordingly, research has shown that while 60–80% of females develop diabetes,  in male NOD mice the prevalence is only 20-30%.  

Therefore, this has great practical implications for study design of preclinical efficacy studies, meaning that fewer animals are needed to achieve adequate group sizes and, therefore, statistical power to detect significant results.   

Reach out to our team to discuss considerations for your NOD mouse model efficacy study design including sex selection, study designs (i.e., preventative or curative), readout selection and endpoint criteria.  

The critical distinction between the NOD mouse model and a chemically induced mouse model lies in the mechanism of beta cell loss. The NOD mouse model presents with spontaneous diabetes development due to a polygenic genetic background that promotes immune dysregulation, loss of self-tolerance, and T-cell-mediated destruction of pancreatic beta cells. In the NOD mouse, autoreactive T cells begin infiltrating the pancreatic islets from approximately 3–4 weeks of age, progressively destroying insulin-producing beta cells through a staged immune process that mirrors the immunological sequence of human type 1 diabetic disease onset.  

In contrast, STZ-induced diabetes mouse model relies on beta cell cytotoxicity rather than autoimmune destruction, failing to recapitulate the preclinical autoantibody phase seen in humans. It is, however a fast, highly reproducible preclinical mouse model of diabetes that is well-suited to evaluate early efficacy of insulin replacement strategies, glucose-lowering compounds, and beta cell regeneration approaches.  

Similarly, the STZ-induced diabetes mouse model and the alloxan-induced diabetes mouse model lead to rapid chemically induced hyperglycemia without an autoimmune component. Alloxan is an urea derivative that induces selective necrosis of pancreatic islet beta cells by generating highly reactive hydroxyl radicals that cause DNA fragmentation.  

Therefore, for programmes targeting the autoimmune mechanisms of T1D, the NOD model is the appropriate choice. For rapid, reproducible beta cell ablation independent of immune mechanisms, STZ or alloxan are the most practical platforms and often most useful for early-stage efficacy. 

Contact our team to discuss which model best fits your compound’s mechanism and development stage. 

InnoSer supports three distinct intervention paradigms in the NOD mouse model, each designed to address a different therapeutic hypothesis and stage of disease: 

• Prevention studies(prediabetic window): Prevention studies in the NOD mouse model are initiated before insulitis onset and overt disease establishment, marking the earliest and most immunologically permissive window. This design is most relevant for immune tolerance-inducing approaches and prophylactic immunotherapy strategies. 

• Prevention studies (early-onset window): Preventive studies can be performed in the NOD mouse model during the early disease-onset window, which arises as a critical checkpoint where nondestructive peri-insulitis transitions into destructive intrainsulitis. Similarly to running prevention studies in the prediabetic window, this study design is most suitable for immune-based approaches.  

• Therapeutic intervention studies(dosing starts once disease isestablished): Type 1 diabetes in the NOD mouse model is defined as confirmed blood glucose above 250 mg/dL on two consecutive measurement timepoints, meaning that dosing typically begins around weeks 20 of age (median age of diabetes onset in the NOD mouse model at InnoSer labs was 19 weeks of age, see figures in the section above). These paradigms address the most clinically relevant patient population: individuals who already have overt T1D and require disease modification or beta cell preservation rather than prevention. Compared to prevention studies, therapeutic intervention studies are most suitable for efficacy evaluation of combination strategies focusing on immune modulation as well as therapies that promote beta cell regeneration.  

Importantly, all study timelines and intervention windows are thoroughly discussed with InnoSer’s scientific team based on your compound’s mechanism, dosing requirements, and target endpoints. 

Contact us to discuss the optimal intervention window for your programme now.