Simultaneous assessment of autonomic nervous and vascular endothelial functions in a rat model

Despite the importance of translational medicine in cardiovascular research, rat vascular endothelial function and sympathetic activity assessment remains challenging.This study consisted of two parts: part A examined the consistency of reactive hyperemia-elicited dilatation index(DI) before (DI Original ) and after (DI EEMD ) ensemble empirical mode decomposition (EEMD) using Wistar-Kyoto (WKY)rats (n = 7). Part B compared the endothelial function and heart rate variability of normal WKY rats (group 1, n = 9)with those of spontaneously hypertensive rats (group 2,n = 9) at two time points of development. The SD1/SD2 ratio(SSR) was obtained from Poincaré plot analysis to evaluate sympathetic activities. Using a Bland-Altman plot, part A of the study demonstrated a lower agreement of DI Original than that of DI EEMD . In part B, despite no significant difference in DI EEMD between the two groups at age 10 weeks, DI EEMD was higher in group 1 (2.25 } 0.63 vs. 1.43 } 0.41 for groups 1 and 2, respectively, p = 0.004) at 20 weeks. Although no notable change in SSR existed in group 1 between the twotime points, a significant difference existed in group 2(p < 0.001). In conclusion, using algorithms of Poincaré plot analysis and EEMD, the impact of age and hypertension on rat vascular endothelial function and heart rate variability can be reliably assessed.