Effects of Astaxanthin on Pulse Rate Variability of Mice Under Chronic Stress

Abstract

This exploratory study aims to evaluate the autonomic cardiovascular effects of the astaxanthin on pulse rate variability (PRV) of chronically stressed mice. We used male CD1 mice that were divided into four groups: l-control (Ct, n = 3), ll-chronic restraint stress (St, n = 4), III-supplemented with astaxanthin (Astx, n = 4) and IV-supplemented and stressed (Astx + St, n = 5). Astaxanthin (4 mg/kg for 21 consecutive days) in the corresponding groups was orally administered. In the last day, the pulse rate signals were recorded by photoplethysmography. One minute of pulse-to-pulse time series (P-P) were constructed for all the groups. The P-P time series were processed to estimate relevant linear and nonlinear PRV parameters. It was found that in stressed mice, astaxanthin produced: (1) decreased heart rate; (2) increased complexity in the P-P time series and (3) increased fractal behavior in the pulse rate fluctuations. These results suggest that astaxanthin may attenuate the autonomic cardiac imbalance produced by chronic stress.