[Health effects of formaldehyde, as an indoor air pollutant].
Hazard Evaluation & Epidemiology Research Group, National Institute of Occupational Safety and Health, Nagao 6-21-1, Tama-ku, Kawasaki 214-8585, Japan. Kaibogaku Zasshi
Formaldehyde is an important chemical used widely by industry in numerous household products. Therefore, when room ventilation is inadequate, formaldehyde may stagnate in rooms and adversely affect the health of inhabitants. Exposure to formaldehyde in living space has been found to be associated with asthma and 'sick house syndrome' (health disturbances induced by chemical contaminants in domestic environments). In addition, formaldehyde exposure among medical students and teachers who dissect cadavers in the gross anatomy laboratory likely causes a health problem. Avoidance of formaldehyde exposure can reduce the incidence and severity of ill-health conditions, although the ability of low concentrations of formaldehyde to trigger mechanisms contributing to them is still debated. Setting appropriate exposure limits for formaldehyde as an indoor environmental pollutant requires further quantitative and predictive evaluation of its health effects.
Available from: Wen-Liang Zhou
- "Furthermore, formaldehyde has strong carcinogenic effects on human . In the past, formaldehyde was classified mostly as a compound from extraneous contamination . But recent investigations showed that in vivo methylamine can be catalyzed into formaldehyde by semicarbazide-sensitive amine oxidase , . "
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Recent studies suggest that formaldehyde (FA) could be synthesized endogeneously and transient receptor potential (TRP) channel might be the sensor of FA. However, the physiological significance is still unclear.
The present study investigated the FA induced epithelial Cl- secretion by activation of TRPV-1 channel located in the nerve ending fiber. Exogenously applied FA induced an increase of ISC in intact rat trachea tissue but not in the primary cultured epithelial cells. Western blot and immunofluorescence analysis identified TRPV-1 expression in rat tracheal nerve ending. Capsazepine (CAZ), a TRPV-1 specific antagonist significantly blocked the ISC induced by FA. The TRPV-1 agonist capsaicin (Cap) induced an increase of ISC, which was similar to the ISC induced by FA. L-703606, an NK-1 specific inhibitor and propranolol, an adrenalin β receptor inhibitor significantly abolished the ISC induced by FA or Cap. In the ion substitute analysis, FA could not induce ISC in the absence of extracelluar Cl-. The ISC induced by FA could be blocked by the non-specific Cl- channel inhibitor DPC and the CFTR specific inhibitor CFTRi-172, but not by the Ca2+-activated Cl- channel inhibitor DIDS. Furthermore, both forskolin, an agonist of adenylate cyclase (AC) and MDL-12330A, an antagonist of AC could block FA-induced ISC.
Our results suggest that FA-induced epithelial ISC response is mediated by nerve, involving the activation of TRPV-1 and release of adrenalin as well as substance P.
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ABSTRACT: Formaldehyde (FA), a ubiquitous environmental pollutant, is extensively used in hospitals, laboratories, and industrial settings. Previous studies showed that FA exerts adverse effects on testicular function and as epididymis is known to play an important role in the maturation and storage of sperm, the effects of FA were examined on epididymis. In particular, this study was designed to investigate the influence of FA on structure and function of epididymis in adult male rats using histological and biochemical methods. Sprague-Dawley adult rats were randomly allotted to three groups and exposed to FA at a 0 (control), 0.5, or 10 mg m by inhalation for 28 days. The results indicated that epididymal toxicity of FA was concentration dependent. Epdididymal structure and function in rats of 0.5 mg m FA exposure group showed no apparent difference from control. However, epididymal weight, sperm count and motility, the activities of superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were significantly decreased, whereas the levels of malondialdehyde (MDA) was significantly increased in epididymis of rats exposed to 10 mg m FA. Moreover, microscopy with hematoxylin and eosin (H&E) staining showed atrophy of epididymal tubules, disintegration of epididymal epithelium, disorganization, and even vacuolar denaturalization of epididymal epithelial cells. There was hyperemia in interstitial vasculature and lumina were oligozoospermic in rats of 10 mg m FA exposure group. In conclusion, FA exposure alters the epididymal structure and function by inducing oxidative stress in epididymis of adult rats.
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