Behavioral Characteristics of Normotensive Wistar and Spontaneously Hypertensive Rats with an Experimental Model of Diabetes Mellitus Type 2

Abstract

Introduction: Modern lifestyle is often characterized by decreased physical activity, regular intake of saturated and trans-fatty acids and increased physical and emotional stress, which are a prerequisite for the increased incidence of type 2 diabetes (diabetes mellitus, DM2). Recently published studies showed a positive correlation between DM2 and spontaneous hypertension in the deterioration of the sensory nerve function and the occurrence of peripheral diabetic neuropathy. The purpose of this study was to characterize the behavioral changes induced by an experimental model of diabetes in normotensive and spontaneously hypertensive rats. Materials and Metods: DM2 was induced by the combination of a high-fat diet (2 months) with a sub diabetogenic dose of streptozotocin (30 mg/kg, intraperitoneally). The experimental model of DM2 was induced in two rat strains: normotensive Wistar and spontaneously hypertensive rats (SHR). The exploratory activity and locomotion were studied by an open field test, the level of anxiety by an elevated plus maze test and working memory was tested by an object recognition test. Results: The present results confirmed that SHRs are characterized by higher motor activity and less anxiety-like behavior compared to normotensive Wistar rats. DM2 induced a remarkable decrease in motor activity in both strains. However, this effect was more pronounced in SHRs. Moreover, DM2 impaired the working memory in SHRs without affecting this type of memory in normotensive animals. Conclusions: Data from this study showed that SHRs are more vulnerable to DM2 in regard to behavioral alterations provoked by the metabolic disease. The results could provide a basis for further testing of the effects of existing and new antihypertensive and antidiabetic drugs on the comorbid hypertension with diabetes type 2.