Chronic noise exposure in the spontaneously hypertensive rat

Abstract

Introduction:Epidemiological studies have suggested an association between the relative risk for developing cardiovascular disease (CVD) and long-term exposure to elevated levels of transportation noise. The contention is that this association is largely owing to an increase in stress-related biomarkers that are thought to be associated with CVD. Animal models have demonstrated that acute noise exposure is capable of triggering a stress response; however, similar studies using chronic noise models are less common.Materials and Methods:The current study assessed the effects of intermittent daily exposure to broadband 80 kHz bandwidth noise of 87.3 dBA for a period of 21 consecutive days in spontaneously hypertensive rats.Results:Twenty-one days of exposure to noise significantly reduced body weight relative to the sham and unhandled control groups; however, noise had no statistically significant impact on plasma adrenocorticotropic hormone (or adrenal gland weights). Noise was associated with a significant, albeit modest, increase in both corticosterone and aldosterone concentrations following the 21 days of exposure. Interleukin 1 and interleukin 6 levels were unchanged in the noise group, whereas both tumour necrosis factor alpha and C-reactive protein were significantly reduced in noise exposed rats. Tail blood sampling for corticosterone throughout the exposure period showed no appreciable difference between the noise and sham exposed animals, largely due to the sizeable variation for each group as well as the observed fluctuations over time.Discussion:The current pilot study provides only modest support that chronic noise may promote stress-related biological and/or developmental effects. More research is required to verify the current findings and resolve some of the unexpected observations.

Chronic noise-exposure exacerbates insulin resistance and promotes the manifestations of the type 2 diabetes in a high-fat diet mouse model

“…Increased circulating FFA resulting from stress hormone-induced lipolysis has been suggested to be an important causative link between the stress response, insulin resistance and T2DM[ 28 , 35 ]. Consistent with previous animal studies focused on the effect of chronic noise on body weight [ 36 , 37 ], noise exposed mice in present study displayed decreased body weight gain compared with their diet-matched counterparts. As no significant differences in food consumption were found between the diet-matched groups, the decreased body weight gain as well as increased circulating FFA observed in noise exposed mice might be interpreted as catabolic consequences of noise stress.…”

Long-Term Effects of Aircraft Noise Exposure on Vascular Oxidative Stress, Endothelial Function and Blood Pressure: No Evidence for Adaptation or Tolerance Development

“…In humans the release of the stress hormone cortisol was reported for acute (Gitanjali and Ananth, 2003;Pouryaghoub et al, 2016) and chronic noise exposure (Ising and Ising, 2002;Selander et al, 2009), suggesting that there was no habituation regarding the stress response. These clinical data were also supported by observations in animals that were exposed to acute or chronic noise challenges (Chandralekha et al, 2005;Konkle et al, 2017). Similar data exist for catecholamine release upon acute (Maschke et al, 1993;Schmidt et al, 2013) and chronic noise exposure of humans (Ising et al, 1999;Babisch et al, 2001).…”

Characterization of Anxiety-Like Behaviors and Neural Circuitry following Chronic Moderate Noise Exposure in Mice

“… 2 , 38 This study used white noise because it contains all frequencies across the audible spectrum and has been commonly used in laboratory experiments to mimic environmental noise. 16 , 39 , 40 Similar protocols (85–90 dB SPL, 4–12 h/d, 21–56 d) have been used to examine the effects of noise on sleep 41 and stress hormones 42 in rats and insulin resistance 43 and immunity 44 in mice. Our previous discovery of acute, white noise–evoked mouse escape implied that sudden noise may be linked to negative emotion.…”