Effect of Different Periods of Traffic Noise Exposure on Epinephrine, Norepinephrine and Corticosterone Serum Level Changes in Male Rat

Background and Objectives: Traffic noise, as one of the noise types, is a widespread feature of the urban environments. Traffic noise exposure can lead to hearing loss, hypertension, obesity and ischemic heart diseases. Stress also has many physiological effects on the hormonal and neural function. Therefore, this study was designed to evaluate different periods of traffic noise effects on the levels of adrenal stress hormones in male rats. Methods: 48 male wistar rats were used in this study. They divided randomly into 6 groups; the control, short term (1 day) and long term (7, 14, 21 and 28 days) groups. Traffic sound was recorded, adjusted and played (86 dB) for animals. At the end of experiment, the animals were anesthetized and blood sample was drawn. Levels of epinephrine, norepinephrine and corticosterone were measured. Statistical analysis was done by one-way analysis of variances and Tukey’s post hoc test. Results: Findings showed that in the 1 day group, epinephrine level decreased and in the 21 days group significantly increased. Levels of norepinephrine showed significant increase in the 14, 21 and 28 groups. In the same way, concentration of corticosterone significantly increased with increase of traffic noise time. Conclusion: It seems that traffic noise exposure led to decrease of epinephrine plasma concentration in the short term while it increased all of 3 hormones in the long term. It may be due to hormonal structure, half time and stress period.