Protective effects of Digera muricata (L.) Mart. against carbon tetrachloride induced oxidative stress in thyroid of rat

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 the thyroid. 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 TT₃ and TT₄ was significantly decreased, while TSH level was increased with CCl₄ treatment. 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