Abstract

Protective effects of Digera muricata (DM) methanol extract (DME) were evaluated against the oxidative stress of carbon tetrachloride (CCl₄) in the thyroid of male Sprague-Dawley rats. Treatment of CCl₄ 1 ml/kg bw (25% CCl₄/olive oil i.p) once a week for 16 weeks significantly decreased the activities of catalase, peroxidase, superoxide dismutase, glutathione-S-transferase and glutathione peroxidase in thethyroid. Level of reduced glutathione was decreased, while lipid peroxidation (TBARS) was significantly increased with CCl₄ in the thyroid of rat. CCl₄ significantly enhanced the level of thyroidal DNA injuries and AgNORs count. Serum level of TT₃and TT₄ was significantly decreased, while TSH level was increased with CCl₄treatment. Pleiomorphic histopathological abnormalities in thyroid were caused by CCl₄ treatment. Co-treatment of DME (100 and 200 mg/kg bw) intragastrically once a week for 16 weeks suppressed the toxic effects of CCl₄ and level of thyroid hormones, the activities of oxidative enzymes, glutathione (GSH) and TBARS concentration. Histopathological injuries induced with CCl₄ were remarkably reduced with co-treatment of DME in a dose dependent fashion. These results suggest that the ameliorative effects of DME could be attributed to radical scavenging or antioxidant properties.

Key words: Thyroid hormone, carbon tetrachloride, peroxidase, lipid peroxidation (TBARS), Digera muricata, argyrophilic nucleolar organizer region.

Abbreviation

DM, Digera muricata; DME, Digera muricata methanol extract;CCl₄, carbon tetrachloride; AgNORs, argyrophilic nucleolar organizer regions.