Comparison of the Effects of Melatonin, Tymoquinone and Amifostine on Peripheral Blood Cells During Total Body Irradiation in Rats

Abstract

Ionizing radiation-induced free radicals causes functional and structural harmful effects through the cell membranes. Melatonin, a well-known powerful antioxidant, can play a role in the prevention of oxidative damage. It also has the ability to protect the genetic material of hematopoietic cells of mice from damaging effects of acute total body irradiation. The objective of this study was to assess the potential radioprotective effects of Melatonin, Thymoquinone (TQ) and Amifostine in peripheral blood cells of rats received total body irradiation. Thirty-eight adult Sprague-Dawley rats were divided into 5 groups. Group 1 (n=6) received no melatonin, amifostine, thymoquinone or irradiation (sham control group). Group 2 (n=8) received only total body irradiation (IR) of 6 Gy. Group 3 (n=8) received irradiation and melatonin (10 mg/kg, i.p., 30 min before IR), Group 4 (n=8) received irradiation plus amifostin (200 mg/kg 30 min. before IR) and Group 5 (n=8) received irradiation plus thymoquinone (10 mg/kg, i.p, 30 min before IR). One and a half hour following IR, blood samples were taken. Leukocytes, thrombocytes and erythrocytes counts were measured in all groups. Statistical analysis was performed using the SPSS (Statistical Package for Social Science; Windows version 16.0) packed program. The statistical comparison of results has been performed by using paired samples Student’s t-test. In preventing irradiation induced leukopenia and thrombocytopenia, Thymoquinone and Amifostine were as effective as melatonin. Tymoquinone and amifostine protected leukocyte and thrombocyte count against irradiation. There was no significant difference in erythrocyte count (Table).Poster Viewing Abstracts 3353; Table 1Leucocyte and Thrombocyte and Erythrocyte Counts in All GroupsGroupsLeucocyte (x103/uL)Thrombocyte (x103/uL)Erythrocyte (106/uL)Sham control (1)10,77±1,42*525,140±86,08†8,398±0,115Irradiation (2)7,93±0,91261,160±45,507,928±0,760Melatonin plus irradiation (3)10,37±1,58*516,420±128,41#9,682±0,160Amifostine plus irradiation (4)10,15±3,52*444,660±71,36†8,630±0,133Timoquinone plus irradiation (5)12,58±2,14*470,600±88,72#9,338±0,207* p<0.05; with respect to irradiation, by Student’s t-test. †p = 0.001; with respect to irradiation, by Student’s t-test. # p<0.01; with respect to irradiation, by Student’s t-test. Open table in a new tab * p<0.05; with respect to irradiation, by Student’s t-test. †p = 0.001; with respect to irradiation, by Student’s t-test. # p<0.01; with respect to irradiation, by Student’s t-test. Our results suggest that Melatonin, TQ and Amifostine administration prior to radiation prevents radiation damage on peripheral blood cells. This radioprotection is achieved by their ability as a scavenger for free radicals generated by ionizing radiation acts probably as a growth factor, especially for granulocytes in bone marrow as Melatonin.