Non-Invasive Blood Pressure Measurement in Conscious and Anesthetized UCD-Type 2 Diabetes Mellitus Rats

Arterial hypertension is the primary comorbidity associated with type 2 diabetes mellitus (T2DM) and contributes to increased mortality among these patients. Given their heightened cardiovascular risk, longitudinal blood pressure (BP) monitoring represents a clinically relevant marker for early detection of hypertension and subclinical disease progression. However, most human studies rely on acute BP measurements and often lack clarity regarding disease onset and duration. In animal models, BP is typically assessed by invasive surgical methods under anesthesia, limiting a direct translational relevance to patients with T2DM. As a result, the BP pattern across stages of T2DM remains unclear. Therefore, this study aims to evaluate BP across different phases of the disease in T2DM rats, and to assess the effects of anesthesia in this measurement. Experiments were performed on adult male University of California Davis (UCD)-T2DM rats (n=15) at four different time-points of the disease: pre-diabetic (at 12 weeks old), at the onset of the disease, 4 weeks after onset and 10 weeks after onset. Healthy age-matched Sprague-Dawley rats (n=16; Charles River Laboratory) served as controls. Fasted blood glucose, hemoglobin A1c (HbA1c), body weight, and abdominal circumference were assessed in all animals. Non-invasive BP measurements were performed via tail-cuff system in conscious and anesthetized (3-5% isoflurane) rats. All rats underwent a familiarization period to allow acclimation to the restrainer. T2DM rats were compared to controls using an independent t-test. BP measurements were analyzed using a two-way ANOVA with repeated measurements followed by Fisher’s LSD post-hoc test. Data collection have been completed for the pre-diabetic stage, as this is an ongoing project, and are presented as mean ± SD. Although T2DM rats exhibited higher HbA1c, body weight and abdominal circumference compared to healthy controls (HbA1c: 5.1 ± 0.4% vs 4.3 ± 0.2%; body weight: 442 ± 24g vs 393 ± 43g; abdominal circumference: 19.9 ± 0.6 cm vs 18.6 ± 1.3 cm, all p< 0.001), glucose was similar between groups (T2DM: 102 ± 9 mg/dL vs healthy: 101 ±12 mg/dL, p=0.464). Conscious T2DM rats exhibited higher BP and heart rate (HR) compared to healthy controls (SBP: 171 ± 15 mmHg vs 123 ± 21 mmHg; DBP: 116 ± 17 mmHg vs 81 ± 15 mmHg; mean BP: 134 ± 16 mmHg vs 95 ± 17 mmHg; HR: 362 ± 77 bpm vs 279 ± 64 bpm, all p< 0.001). Importantly, anesthesia attenuated BP in both T2DM and healthy rats (all p< 0.05 for condition), and increased HR in healthy rats (p< 0.05). As the magnitude of change was greater in T2DM rats, the differences between groups were abolished under anesthesia. These preliminary findings indicate that conscious T2DM rats have higher BP and HR compared to controls when measured using a non-invasive tail-cuff method. Since differences were eliminated during anesthesia, we suggest T2DM rats may exhibit an exaggerated cardiovascular response to the stress associated with this BP measurement method. This project was supported by the Research Enhancement Program funds from Texas State University. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.