Subacute subchronic toxicity of formaldehyde by inhalation in male albino rats: histopathological and image analysis studies on nasal mucosa

ABSTRACT

This study aimed to evaluate the inhalation toxicity to the nasal epitheliumof rats, formaldehyde [HCHO] at a high concentration for both short andmoderate periods. 24 adult male albino rats were exposed to a concentrationof 30 ppm formaldehyde vapor during 6 hours/day, 5 days/week for successive 4,8 and 12 weeks, respectively. Histopathological examination as well asassessment of the DNA content of mucosal nuclei using the computerized imageanalysis [IA] system were both done. Histopathological examination revealedthat the aldehyde produced both involutional changes, such as erosion andatrophic epithelium, and proliferative reactions, such ashyperplastic-metaplastic as well as dysplastic lesions. Furthermore, all thelesions elaborated diploid histograms with variable degree of statisticallysignificant increases of mucosal cells at the S- phase compared with thecontrol. Therefore, the results indicated that there was an increasedreactivity of the nasal mucosal cells towards formaldehyde vapor