Background: Altered autonomic cardiovascular regulation (ACR) may mediate the association between single-wall carbon nanotubes (SWCNT) exposure and adverse cardiovascular events.
Material and methods: 400 mg of SWCNT in 400 ml of phosphate buffer saline (PBS) or 400 ml of PBS were randomly given to 7 Wystar-Kyoto rats (400 g body wt) previously implanted in abdominal aorta with a telemetry transmitter for recordings of arterial pressure signals. Recordings were performed at baseline, 24 hours and two weeks after intratracheal instillation. The beat-by-beat time series of systolic arterial pressure (SAP) and PR interval were analyzed to identify sequences of three or more consecutive beats in which SAP and PR changed in the same (baroreflex sequences) or in the opposite direction (nonbaroreflex sequences). The mean individual slope of the sequences was calculated and taken as a measure of the baroreflex (BRS) and nonbaroreflex sensitivity for that period.
Results: The 24 hour BRS response showed a 100% increase (from 4.6 to 9.2 msec/mmHg) in controls, whereas it was blunted in cases (from 5.1 to 6.1 msec/mmHg) (p < 0.05).
Conclusions: Our study demonstrates that this rat model is suitable to study the ACR during exposure to SWCNT and suggests a blunted BRS response after SWCNT instillation.