Benzo(a)pyrene [B(a)P] is known to alter lung physiology by interfering in various intracellular pathways including alterations in NF-κB activities,
cytokine release and cell survival. NF-κB suppression/activation plays a major role in cell survival status. Present investigation deals with such kind of effects of B(a)P on lungs in relation with soluble
epoxide hydrolase (sEH) and
thioredoxin reductase (TrxR) activities.
Glycyrrhizic acid (GA), an active principle of Glycyrrhiza glabra (Licorice), is known to modulate various molecular processes. In the present study, we investigated the protective effects of GA against B(a)P induced
debilities in lungs of Wistar rats. Intratracheal instillation of B(a)P significantly suppressed NF-κB translocation, sEH, TrxR and
catalase activities in lung tissue. A marked induction of H(2)O(2) levels along with
caspases activation (caspases-2, -3, -6, -8, and -9) in lung tissue after B(a)P exposure was observed.
Lung injury was assessed by measuring
lactate dehydrogenase (LDH),
alkaline phosphatase (ALP), total cell count, total
protein,
neutrophil elastase activity in bronchoalveolar lavage fluid (BALF). Reduction in
phospholipid content further potentiated these parameters. GA
oral administration (50 and 100mg/kg b.wt.) significantly showed protection of lung epithelium by suppression of
caspases activities in lung tissue and reduction of total
protein, total cells,
elastase activity, LDH and ALP activities along with fortification of
phospholipids in BALF. Histological observations also confirm the findings in above mentioned parameters. Results indicate a strong correlation between amelioration of sEH and TrxR activities, and NF-κB activation. The present investigation gives an insight into probable mechanisms of
lung injuries induced by short term exposures of B(a)P and prevention by
glycyrrhizic acid.