Effect of bisphenol-A on the lung of adult male albino rats and the possible protective role of geraniol: a histological and immunohistochemiacal study

ABSTRACT

Concern is mounting regarding the human health and environmental effects of bisphenol A [BPA], a hormone-disrupting chemical used in plastic and epoxy resin industries. Geraniol [a plant-derived terpene] has cytoprotective and antioxidant potential. This work aimed to study the effect of BPA on the lung of adult male albino rats, assess different dose responses of BPA, and evaluate the possible protective role of geraniol supplementation using histological and immunohistochemical methods. Thirty-five adult male albino rats were divided into seven equal groups. All treatments were given by oral gavage for 8 weeks. Group I served as the untreated control group. Group II received corn oil [0.5 ml/day]. Group III was given geraniol [150 mg/kg body weight/on alternate days]. Groups IV, V, and VI received BPA [5, 50, and 500 mg/kg body weight/day, respectively]. Group VII was treated with BPA [500 mg/kg body weight/day] along with geraniol at a similar dose. Lung specimens were taken and processed for H and E, Masson's trichrome stains, and for immunohistochemical staining of alveolar macrophages [CD68] and inducible nitric oxide synthase [iNOS]. The area percentage of positive iNOS immunoreactivity and the count of alveolar macrophages in immunostained sections were morphometrically and statistically analyzed. Group IV revealed similar results to the control group. Groups V and VI showed disrupted lung architecture with collapsed alveoli, inflammatory cellular infiltration, congested thickened pulmonary vessels, extravasated red blood cells, and collagen fiber deposition. There was a significant increase in the area percentage of positive iNOS immunoreaction and in the count of alveolar macrophages, compared with the control group. These effects were more pronounced in group VI. Coadminstration of BPA and geraniol [group VII] preserved a near-normal lung structure. Long-term administration of BPA caused dose-dependent lung damage, which could be significantly ameliorated by concomitant treatment with geraniol