Effects of high frequency noise on female rat's multi-organ histology.

To investigate the pathological damage of high-frequency stable noise exposure on the brain, heart, liver, and spleen of female rat's. Controlled animal intervention study. Twenty female Sprague-Dawley rats were randomly divided into experimental and control groups with 10 rats in each group. Rats in the experimental group were exposed to continuous high-frequency stable noise for 2 weeks (3 h/day)followed by the pathological damages in the rat's brain, heart, liver, and spleen were compared with those of the control group. After 2 weeks' continuous exposure to high-frequency stable noise, compared with the control group, the most prominent histopathologic changes in the brain tissue structures of the experimental group included loose disorder, hyperemia, edema, blood vessels expand, glial cell hyperplasia, mild atypia in some areas (hyperchromatic nuclei, irregular karyotype), and no degeneration and necrosis. There were dilatation and congestion of central vein, hepatic sinus, and interlobular veins of liver tissue. The structure of hepatic lobule was destroyed by inflammatory cell infiltration, as well as lymphoid nodule formation. There was hyperemia in spleen, but the structure was clear. There was extravasated blood, and the splenic sinuses were highly expanded by a blood clot. Hyperplasias of the lymphoid of white pulp were also active. There was dilation and congestion in myocardial interstitial vascular, and there was mild degeneration and hyperemia in myocardial cells. No hemorrhage and myocardial necrosis were observed. High-frequency stable noise can cause pathological damage in brain, liver, spleen, and heart tissues of female rat at a various degree.