Medicinski Glasnik (Feb 2011)
B-type natriuretic peptide (BNP) serum levels in rats after forced repeated swimming stress
Abstract
Aim To estimate the effects of forced repeated swimming stress on BNP serum levels in rats. Methods Adult male Wistar rats weighting between 280-330 g were divided into two groups: control group (n =8) and stress group (n =8). Rats in the stress group were exposed to forced swimming stress daily, for 7 days. The rats were forced to swim in plastic tanks (90 cm wide, 120 cm deep) containing tap water (temperature ca. 25°C). The depth of water was 40 cm. Duration of each swimming session progressively increased from 10 minutes on the irst day to 40 minutes on days 6 and 7. Rats were sacriiced and blood was drawn from abdominal aorta for BNP analysis immediately after the last swimming session. B-type natriuretic serum level was determined by ELISA method using RAT BNP-32 kit (Phoenix Pharmaceutical Inc.). Results There was no statistically signiicant difference between mean BNP serum level in the stress group after the swimming period (0.81±0.14 ng/ml) as compared to the unstressed group of rats (0.8 ±0.08ng/ml). After the swimming period mean body weight slightly decreased in the stress group in comparison with values before stress period (296.3 g vs.272.8 g), but this difference was not statistically signiicant. The stress period had no inluence on food intake in the stress rat group. Conclusion The workload consisting of 40-minutes long swimming session is not suficient to provoke BNP release from myocardium in rats.
