Evaluating the effect of simultaneous exposure to noise and toluene on biological and immunological parameters in rabbits

Abstract

Background and Purpose: Noise is one of the most important physical harmful factors that people are exposed to it in different environments. On the other hand, toluene is also used as a solvent in many industries and many people are exposed to it. Since many industries and factories around the world, especially the chemical and petrochemical industries, are exposed to simultaneous exposure to noise and toluene, this study evaluated the impact of exposure to noise, toluene and simultaneous exposure to noise and toluene on some biological and immunological parameters in rabbits. Methods: This study was carried out using 24 adult male New Zealand white rabbits divided into four groups of 6 each. The groups were divided into: group 1 (exposure to noise only), group 2 (exposure to toluene only), group 3 (simultaneous exposure to noise and toluene) and group 4 (control). Exposure duration for all groups was 112 hours (14 consecutive days and 8 hours daily). The concentration of toluene was 1000±50 ppm and noise intensity was 100±5 dB sound level (dB) with bandwidth of 70-8000 Hz at 1/3 octave-band. The biological factors which measured in this study included uric acid, creatinine, cholesterol, triglycerides and glucose, and the immunological factors which measured in this study included TNF-α and IL-β. Animals blood samples were measured before exposure and on different days after the end of exposure (on immediately after the end of exposure, the 3rd day after the end of exposure, the 7th day after the end of exposure, and on the 14th day after the end of exposure). Comparison of different groups and different repeats was performed using SPSS 24 software and generalized estimating equations (GEE) statistical method. Results: The results of this study showed that serum level of glucose were significantly (P <0.05) increased after the end of exposure to noise and toluene and uric acid and cholesterol levels were significantly (P <0.05) decreased at different days after the end of exposure. Also, the results of this study showed that inflammatory factors (IL-β and TNF-α) were significantly (P <0.05) increased by simultaneous and non-simultaneous exposure to noise and toluene in the early days of exposure, and were significantly decreased (P <0.05) at the final days after the end of exposure. Discussion & Conclusion: Based on the results of this study, it can be concluded that simultaneous and non-simultaneous exposure to high levels of noise and toluene can cause significant changes in the levels of various biological and immunological factors. Furthemore, the interaction type of simultenoues exposure to noise and toluene were dissimilar in different days after exposure. Therefore, considering different changes in levels of various biological and immunological factors due to exposure to noise and toluene can play an important role in the prevention and recognition of various occupational diseases. Moreover, the results of this study can improve occupational toxicology knowledge.