title: The flavonolignan-silymarin protects enzymatic, hematological, and immune system against γ-radiation-induced toxicity.
abstract: The main focus of this study is evaluation of radioprotective efficacy of silymarin, a flavonolignan, against γ-radiation-induced damage to hematological, vital organs (liver and intestine), and immune system. Survival studies revealed that silymarin (administered orally for 3 days) provided maximum protection (67%) at 70 mg/kg body weight (b.wt.) against lethal 9 Gy γ-irradiation (dose reduction factor = 1.27). The study revealed significant (p < 0.05) changes in levels of catalase (12.57 ± 2.58 to 30.24 ± 4.89 units), glutathione peroxidase (6.23 ± 2.95 to 13.26 ± 1.36 µg of reduced glutathione consumed/min/mg protein), glutathione reductase (0.25 ± 5.6 to 11.65 ± 2.83 pM NADPH consumed/min/mg protein), and superoxide dismutase (11.74 ± 0.2 to 16.09 ± 3.47 SOD U/mg of protein) activity at 30th day. Silymarin pretreated irradiated group exhibited increased proliferation in erythrocyte count (1.76 ± 0.41 × 10(6) to 9.25 ± 0.24 × 10(6) ), hemoglobin (2.15 ± 0.48g/dL to 14.77 ± 0.25g/dL), hematocrit (4.55 ± 0.24% to 37.22 ± 0.21%), and total leucocyte count (1.4 ± 0.15 × 10(6) to 8.31 ± 0.47 × 10(6) ) as compared with radiation control group on 15th day. An increase in CD4:CD8 ratio was witnessed (0.2-1%) at 30th day time interval using flow cytometry. Silymarin also countered radiation-induced decrease (p < 0.05) in regulatory T-cells (Tregs ) (11.23% in radiation group at 7th day versus 0.1% in pretreated silymarin irradiated group at 15th day). The results of this study indicate that flavonolignan-silymarin protects enzymatic, hematological, and immune system against γ-radiation-induced toxicity and might prove useful in management of nuclear and radiological emergencies. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 641-654, 2016.
authors.affiliation: Radiation Biotechnology Group, Division of Radiation Biosciences, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organisation, Brig SK Mazumdar Marg, Delhi, 110054, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Adhikari
authors.affiliation: Radiation Biotechnology Group, Division of Radiation Biosciences, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organisation, Brig SK Mazumdar Marg, Delhi, 110054, India.|Office of the Distinguished Scientist and Director General-Life Sciences, DRDO Head Quarters, DRDO Bhawan, Rajaji Marg, New Delhi, 110011, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Arora
mesh_terms: D000284:Administration, Oral; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005720:Gamma Rays / Q000009:adverse effects*; D006403:Hematologic Tests; D007107:Immune System / Q000187:drug effects / Q000528:radiation effects; D007583:Jejunum / Q000187:drug effects / Q000528:radiation effects; D008099:Liver / Q000187:drug effects / Q000528:radiation effects; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D012838:Silymarin / Q000494:pharmacology*
chemical_list: D011837:Radiation-Protective Agents; D012838:Silymarin
keywords: antioxidant; hematology; radioprotection; regulatory T-cells; silymarin