Many studies have proven that noise exposure is associated with hearing loss, hypertension, and other adverse health effects. However, few studies on the metabolomic effects of noise exposure have been reported.

This study investigates the health effects of noise exposure on Wistar rats, and related changes of selected metabolites in serum and urine.

Male Wistar rats aged eight weeks were randomly divided into a noise exposure group (n=10) and a control group (n=8). The rats in the exposure group were given 85 dB sound pressure level (SPL) broadband noise exposure for 8 h per day, 5 d per week, and lasting for 6 weeks. After the exposure, body weight, organ weight, and blood pressure of rats were measured respectively, hearing threshold was measured by auditory brainstem response (ABR), and selected blood biochemical indicators were detected. After the serum and urine samples of the two groups of rats were collected, the changes in the expressions of small molecule metabolites associated with noise exposure and related pathways were analyzed by untargeted metabolomics analysis using high-resolution quadrupole coupled with time-of-flight mass spectrometer.

Noise exposure had no obvious effects on the body weight, organ coefficient, and blood pressure of the rats (P>0.05). The ABR threshold at 32 kHz was (74.00±5.48) dB in the exposure group, higher than that in the control group(55.00±3.54) dB (P < 0.05). The concentrations of triglyceride, total cholesterol, and high-density lipoprotein in the exposure group were (1.14±0.20), (1.90±0.33), and (1.34±0.25) mmol·L^-1, respectively, all higher than those in the control group(0.75±0.28), (1.58±0.25), and (1.11±0.16) mmol·L^-1, respectively (P < 0.05). However, there was no significant change in low-density lipoprotein concentration between the two groups (P>0.05). The serum metabolomics analysis screened and identified 27 differential metabolites associated with noise exposure, and these metabolites participated in glycerophospholipid metabolism, linoleic acid metabolism, and steroid metabolism. The urine metabolomics analysis screened and identified 18 noise exposure-related differential metabolites which were involved in lipid metabolism, phenylalanine metabolism, and tryptophan metabolism.

Noise exposure can affect the hearing threshold and blood lipid level of rats. In addition, it can also interfere expressions of small molecule metabolites in serum and urine, and disturb glycerophospholipid metabolism, linoleic acid metabolism, phenylalanine metabolism, and other metabolic pathways.