Experimental rodent models of type 2 diabetes: a review

Due to the high prevalence of diabetes worldwide, extensive research is still being performed to develop new antidiabetic agents and determine their mechanisms of action. Consequently, a number of diabetic animal models have been developed and improved over the years, of which rodent models are the most thoroughly described. These rodent models can be classified into two broad categories: 1) genetically induced spontaneous diabetes models; and 2) experimentally induced nonspontaneous diabetes models. The popularity of using experimentally induced nonspontaneous models for diabetes research over that of the genetically induced spontaneous models is due to their comparatively lower cost, ease of diabetes induction, ease of maintenance and wider availability. The various experimentally induced type 2 diabetes (T2D) rodent models developed over the last 30-plus years for both routine pharmacological screening and mechanistic diabetes-linked research trials include: adult streptozotocin (STZ)/alloxan rat models, neonatal STZ/alloxan models, partial pancreatectomy models, long-term high-fat (HF) diet-fed models, HF diet-fed STZ models, nicotinamide/STZ models, intrauterine growth retardation (IUGR) models, the STZ-induced progressive diabetic model and monosodium glutamate (MSG)-induced model. The use of these models, however, is not without limitations. A T2D model should ideally portray an identical biochemical blood profile and pathogenesis to T2D in humans. Hence, this review will comparatively evaluate experimentally induced rodent T2D models considering the above-mentioned criteria, in order to guide diabetes research groups to more accurately select the most appropriate models given their specific research requirements.