The histological effects of formaldehyde vapour on the lungs

This study was designed to investigate the effects 40% formaldehyde inhalation on the lungs. Twenty adult male albino rats were used for this study and they were subdivided into five groups (A, B, C, D, and E) with each group containing 5 rats. The animals in group A served as control, while groups B, C, D and E served as the test groups exposed to forty percent( 40%) formaldehyde for ten (10), fifteen (15), twenty (20) and twenty five (25) days respectively. The animals in each of the groups were sacrificed to harvest the lungs at the end of each stage of the experiment. The harvested lungs were immediately fixed in 10% formalin for 24 hrs before tissue processing was carried out. Lung tissue sections were stained with Haematoxylin and Eosin (H&E) stains and examined microscopically. The histological findings show that exposure to 40% formaldehyde induces pneumonitis, acute lung injury, pulmonary fibrosis, bronchiolar epithelia degeneration, acute purulent bronchitis, cellular pyknosis and chronic lungs injury. Thus, 40% formaldehyde inhalation can induce lungs injury and possibly lung tumors.Keywords: Formaldehyde, Inhalation, Pulmonary histology, Lung injury