Effects of Aqueous Leaf Extract of Psidium guajava on Formaldehyde-induced Interstitial Pneumonitis in Adult Wistar Rats

The most common cause of lung diseases among people with formaldehyde-related occupations is formaldehyde poisoning which has significant morbidity and mortality if left untreated. This study was aimed at investigating the effects of aqueous leaf extract of Psidium guajava on formaldehyde-induced interstitial pneumonitis in adult Wistar rats. Thirty (30) adult Wistar rats weighing between 240 g and 270 g were divided into five (5) groups of six (6) rats per group. Group A rats were administered feed and water only; Group B rats were exposed to 40% formaldehyde via inhalation; Group C rats received 500 mg/kg body weight per day (BWT/D) of Psidium guajava; Group D rats were exposed to 40% formaldehyde via inhalation and received 250 mg/kg BWT/D of Psidium guajava; Group E rats were exposed to 40% formaldehyde via inhalation and received 500 mg/kg BWT/D of Psidium guajava. The dosages of the extract were given for 30 consecutive days via an orogastric tube. Groups A, C, D, and E revealed normal histoarchitecture of the lung; normal alveoli, patent bronchiolar lumen, and normal arteries. There were observable histological variations in the lung tissues of Group B rats which include severe bronchiolar mucosal ulceration, interstitial infiltrates of inflammatory cells, interstitial congestion, and interstitial hemorrhage. These injuries are consistent with usual histological findings in interstitial pneumonitis. It was concluded that Psidium guajava had an ameliorative effect on formaldehyde-induced interstitial pneumonitis in Wistar rats.

Key Words: Psidium guajava, formaldehyde, interstitial pneumonitis, lungs