Benzo(a)pyrene-induced pulmonary inflammation, edema, surfactant dysfunction, and injuries in rats: Alleviation by farnesol

ABSTRACT

Benzo(a)pyrene (B(a)P) is a well-known environmental contaminant and carcinogen. Its sources include tobacco smoke, automobile exhaust, forest fire, and other combustion processes. Farnesol, an active principle of Vachellia farnesiana and other aromatic plants, possesses preventive properties against various toxicities. Present study was designed to estimate chemopreventive effects of farnesol against B(a)P-induced pulmonary injuries. To determine the protective effects of farnesol, it was administered orally at 2 doses (100 and 200 mg/kg body weight [b.w.]) once daily for 14 days. Rats were exposed intratracheally to B(a)P, 5 mg/kg b.w. on days 12 and 14, thereafter assessed for pulmonary toxicities 24 hours post last dose of B(a)P. B(a)P-induced edema, inflammation, oxidative stress, and consequent damages in lungs were assessed in terms of total protein, total cell count, nitric oxide (NO), lactate dehydrogenase (LDH), alkaline phosphatase, and in bronchoalveolar lavage fluid (BALF). B(a)P also reduced the levels of phospholipids (lung surfactants) in BALF. However, pretreatment with farnesol at both the doses significantly reduced the lung injuries and inflammatory responses. Farnesol also protected the levels of phospholipids to normal when compared with control. It also modified the activities of B(a)P metabolizing enzymes NADPH–cytochrome P450 reductase, microsomal epoxide hydrolase (mEH), and glutathione S-transferase (GST) in lung tissue of rats. Present findings suggest a prominent role of farnesol against B(a)P-induced lung inflammation, edema, surfactant dysfunction, and epithelial damages in Wistar rats. In conclusion, farnesol shows lung protection against B(a)P toxicities in Wistar rats.

KEYWORDS :

• bronchoalveolar lavage fluid (BALF)
• environmental contaminant
• intratracheal
• NADPH–cytochrome P450 reductase
• neutrophil elastase
• toxicity