Effect of formaldehyde exposure on structure and function of epididymis in adult rats: a histological and biochemical study

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(-3) 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(-3) 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(-3) 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(-3) FA exposure group. In conclusion, FA exposure alters the epididymal structure and function by inducing oxidative stress in epididymis of adult rats.