Abstract

Benz[a]anthracene is a polycyclic aromatic hydrocarbon (PAH) commonly found in the environment, capable of inducing an inflammatory response that may lead to pulmonary toxicity. Due to a lack of knowledge regarding the signs and pathological damages caused by benz[a]anthracene toxicity, there is a need to investigate its effects in a rat model. The determination of the median lethal dose (LD50) involved nine rats using the up-and-down method, while twenty-four rats were used for the sub-acute toxicity study, divided into four groups of six. The first group received 3 ml/kg of physiological saline daily, and the second, third, and fourth groups were treated with benz[a]anthracene at doses of 12.5, 25, and 50 mg/kg/day, respectively, over a two-week period. Pre-treatment blood samples were collected on days zero (0) and 14 for hematological parameters and oncogenic biomarkers. Additionally, pre-treatment and weekly body weights were measured to calculate physiological parameters, total blood volume, and plasma volume using corresponding formulas. Morbid lung measurements were taken, and tissue samples were evaluated for histological changes. The acute toxicity study revealed that benz[a]anthracene has an LD50 of over 5000 mg/kg, although classical behavioral changes were observed at lower administered doses. After 14 days of benz[a]anthracene administration, there was a corresponding reduction in weight gain (-9.91 ± 10.77, 7.58 ± 9.00, 11.42 ± 9.17 and 31.23 ± 5.89% for 50, 25, 12.5 mg/kg, BW (body weight) and control groups, respectively) and inhibition of hematopoiesis with an increase in doses. A dose-dependent increase in CEA levels was observed across the groups (2.26 ± 0.29, 3.29 ± 0.52, 3.86 ± 0.26 and ng/Ml for 50, 25, 12.5 mg/kg and control groups, respectively), along with some dose-dependent gross and histopathological damages to the lung, such as congestion and damaged alveolar sacs with cellular infiltration.

Key words: Benz[a]anthracene, pulmonary toxicity, tumour marker, physiologic parameters.