Abstract

Background:
The incidence of haze from Indonesian forest and peatland fires is a major concern due to its adverse health effects, particularly due to fine particulate matter (PM2.5) exposure, leading to adverse effects on the lungs.

Aim:
This study designed a whole-body PM2.5 exposure chamber to develop a PM2.5 exposure model with varying concentrations and durations, and then evaluated its impact on lung tissue.

Methods:
Thirty-six male Wistar rats were randomly divided into four groups: a control group and three treatment groups with PM2.5 exposure at concentrations of 300, 500, and 700 µg/m³ for 10, 20, and 30 days. The morphology of PM2.5 was characterized using a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectroscopy (EDS) detector. Lung tissue histology was assessed using hematoxylin and eosin (H&E) for lung injury scoring and Masson’s trichrome (MT) for the percentage of fibrotic areas.

Results:
SEM-EDS results showed particles deposited within the alveolar cavity. The highest PM2.5 exposure group (700 µg/m³) had significantly higher lung tissue injury scores and fibrotic areas than the control group across all durations (p < 0.05).

Conclusion:
Exposure to PM2.5 from peat land-burning smoke causes significant lung tissue injury and fibrosis in a dose-dependent manner in Wistar rats.

Key words: Biomass-burning smoke; Histopathology; Lung injury; Peatland fire; PM2.5.