The Effects of Simultaneous Exposure to Styrene and Noise on Working Memory, Anxiety and Locomotor Activity in Rats

Background: In addition to a variety of organic solvents, workers in many industries are also exposed to excessive noise levels. Objectives: The purpose of this study was to evaluate the co-exposure effects of bandpass noise and styrene on working memory, anxiety, and locomotor activity in rats. Methods: Thirty male Wistar albino rats were used. Animals were divided into 4 groups, including the noise exposure group (1), styrene exposure group (750 ppm), simultaneous subacute exposure to noise and styrene group (100 dB, 750 ppm), and the control group. The exposure duration was 6 hours/day, 6 days/week in 3 consecutive weeks. At the end of the exposure, the locomotor activity and working memory were evaluated using open field test and Y-maze test, respectively. Results: The results showed that simultaneous exposure to noise and styrene significantly decreased locomotor activity compared to the control group (P < 0.0001), whereas noise and styrene alone had no significant effect on locomotor activity. Spontaneous alternation in the simultaneous exposure group showed no significant difference compared with the noise and styrene groups. Also, simultaneous exposure to styrene and noise significantly decreased working memory compared to the control group (P < 0.0001). Conclusions: Co-exposure to noise and styrene have significant destructive effects on the brain and behaviors and these harmful effects should be considered in the workplace. However, further human and molecular studies should be conducted to clarify its accurate effects and mechanisms.