Carotid Artery Stenosis is Exacerbated in Spontaneously Obese Model Rats with Diabetes

Aim: Population studies have shown obesity and diabetes to be risk factors for atherosclerosis. We assessed changes in the common carotid arteries in rat models of obesity and diabetes without hypertension. Methods: Twenty 30-week-old male spontaneously diabetic and obese model Otsuka Long-Evans Tokushima Fatty (OLETF) and 20 control Long-Evans Tokushima Otsuka (LETO) rats were used in the experiments. The animals were considered diabetic if the plasma glucose level peaked at > 300 mg/dL and remained at > 200 mg/dL for 120 minutes. Blood gas physiological parameters were continuously monitored under anesthesia, and the flow of the carotid artery was assessed with ultrasonography. All animals were sacrificed with an overdose of anesthesia at the end of the experiment. Sections of the middle portion of the internal carotid artery were cut and stained with hematoxylin and eosin to assess the overall morphology. Results: All OLETF rats were diabetic, and all LETO rats were non-diabetic. The physiological parameters did not differ significantly between the control and model rats, whereas the carotid artery wall thickness (19.3 +/- 3.2 vs. 6.1 +/- 4.5 mu m) was significantly different between the two groups. The blood flow velocity in the common carotid artery determined using ultrasonography and color Doppler sonography was significantly increased during systole in the model rats compared with that observed in the control rats (203 +/- 20.3 vs. 55.3 +/- 21.4 cm/sec). Conclusions: The OLETF rats were obese, and diabetes worsened the degree of carotid artery stenosis. These results indicate the possibility of new therapies for carotid artery stenosis in obese and diabetic patients.