ABSTRACT
Background: Noise induced hearing loss [NIHL] is one of the most important occupational diseases worldwide. NIHL has been found to be potentiated by some of air pollutants. Exposure to noise plus carbon monoxide is common in occupational and environmental settings. This study was performed to evaluate the effect of noise and carbon monoxide exposure simultaneously on rabbits' hearing system by Auditory Brain stem Response [ABR] assessment
Materials and Methods: In this experimental study, 24 male adult white rabbits were divided to four groups: control group, noise exposure group, noise plus carbon monoxide exposure group and carbon monoxide exposure group. Auditory Brain stem Responses of the four groups were determined: before exposure, 1 hour after exposure and 14 days after exposure by click and tone burst stimulus
Results: The latency mean time of V wave in the ABR test for the group exposed to noise plus carbon monoxide, 1 hour after exposure at 1, 2, 4 and 8 KHz frequency were respectively 5.43+/-0.08, 5.50+/-0.07, 5.71+/-0.07 and 5.75+/-0.07 millisecond. These values were significantly more than the same values in the other groups
Conclusion: NIHL may be potentiated by carbon monoxide in the simultaneous exposure. Thus, it seems occupational and environmental exposure to noise plus carbon monoxide may increases hearing loss risk
ABSTRACT
In present study the effect of vitamin E on diabetes induced nephropathy, plasma antioxidant capacity and lipid peroxidation was investigated. 24 male wistar rats with average body weight of 250 +/- 20 gr were chosen. 16 rats, diabetized by STZ [60 mg/kg B.W, i.p] were divided into 3 groups [n=8] of non-diabetic, diabetic non-treated and diabetic treated with Vit.E [300 mg daily]. After 8 weeks all rats were anaesthetized by hydrate chloral. After blood sampling, kidneys were removed and kept in 10% formalin buffer. Plasma and red blood cells of blood samples were separated. Plasma antioxidant capacity by FRAP method, and malondialdehyde [MDA] as lipid peroxidation indicator were measured. Also renal samples were studied for focal cell proliferation and glomerule and tubule structural changes. MDA in non-diabetic, diabetic and diabetic treated with Vit.E rats was 126.14 +/- 6.6, 245.2 +/- 17 and 170.8 +/- 9 nmol/grHb respectively. Significant attenuation of MDA in diabetic treated with Vit. E rats showed decrease of lipid peroxidation in comparison to the diabetic non treated group [P<0.01]. Antioxidant capacity in the three groups mentioned was 582.7 +/- 23.33, 586.2 +/- 23.79 and 808.7 +/- 30.82 mmol/lit respectively. Plasma antioxidant capacity in Vit.E treated rats showed significant augmentation comparing to the first two groups [P<0.05]. In the non-treated rats, glomerule diffused proliferation, cell diffused inflammation and hyaline changes were seen arteries walls also showes thickening. These changes were significantly reduction in rats treated with Vit. E. This study showed that Vit. E causes decrease the oxidative effects stress and improve diabetes induced nephropathy