Protective Effects of Methanolic Extract of Digera muricata (L.) mart. Against Toxicity Induced by Acrylamide in Rat Lung.

Abstract

Exposure to acrylamide Induces acute lung injuries as well as oxidative stress in rats by formation of free radicals. Extracts of medicinal has been shown to exhibit a pharmacological actions against the pulmonary toxicity of acrylamide. The aim of this study was to evaluate the protective effect of exogenous (oral) Digera muricata extract treatment on acrylamide-induced oxidative stress and pulmonary toxicity in rats at histological and biochemical level. F0l1y eight healthy female albino rats, weighting 190-200 g, were provided by the Animal House of National Institute of Health (NIH) Islamabad and were maintained at the Primate Facility maintained at Quaid-i-Azam University, Islamabad. These rats were divided into eight groups with six rats in each group. Among them group I, comprising of six rats were chosen randomly as control, while group II and were administered with dimethylsulphoxide (DMSO) 5.0 ml/kg b.w. orally once a day for four weeks. Group III was given 200 mg/kg b.w. of methanolic extract dissolved in DMSO once a day for four weeks. Rest of the rats were divided into five groups and were treated with aqueous solution of acrylamide 6 mg/kg b.w. intraperitoneally once a day for two weeks. Group IV was sacrificed afier the acrylamide treatment to collect the lung tissue. Group V remained untreated as such for the rest of the experiment. Group VI, VII and VIII were given 100, 150 and 200 mg/kg b.w. methanolic extract dissolved in DMSO once a day for two weeks. Mean body weight was decreased while lung weight of rats treated with acrylamide was statistically (P<O.O 1) induced as compared to the control group. Treatment of methanolic extract reversed the body and lung weight in a concenh'ation dependent manner as compared to the acrylarnide group (30 days). For histopathological evaluation, lung sections were processed and stained for light microscopy. Representative sections taken [r'om lung tissues of acrylamide treated rat showed the changes in microanatomy by rupturing the alveoli and damaging the cells causing the aggregation of blood capillaries. While in extract treated groups these deleterious histopathological alternation were reduced or absent resulting from acrylamide induced lung injuries. Intense repairing effects of the 150 and 200 mg/kg of the methanolic extract of Digera muricata against the acrylamide were observed in the lungs of rats. Antioxidant status in lung tissues was estimated by determining the activities of peroxides (POD), catalase (CAT), reduced glutathione (GSH) and the level of lipid peroxidation (TBARS), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione-S-transferase activity (GST). Treatment of rats with acrylamide decreased the activity of CAT, POD, SOD, protein and GSH contents while increased the TBARS and H20 2 contents in lung tissues of rats as compared to control group. Total protein content of tissue was also measured. To determine the DNA damage in lung tissues; DNA fragmentation and DNA ladder assay was performed. Rats with acrylamide decreased the protein contents in lung tissues of rats as compared to control group. An increase in protein content was observed with the methanolic extract of Digera muricata in lung tissues of rats in a dose dependent manner. DNA fragmentation and DNA ladder assay revealed DNA damage in lung tissues ohats treated with acrylamide as compared to control group. Co-administration of the extract of Digera muricafa decreased the DNA fragmentation% as compared to the acrylamide group in a dose dependent matmer which confirms the restoration. In case of acrylamide (15 days and 30 days treated rats) DNA samples showed a peculiar type of continuous pattern of DNA fragmentation which was absent from the lungs of control rats. Our results demonstrated that Digera muricafa may contain antioxidant metabolites which effectively ameliorated acrylamide induced pulmonary toxicity.