Effects of melatonin, amifostine and thymoquinone on liver Na ⁺ /K ⁺ -ATP’ase enzyme activity in total body irradiated rats

Abstract Objectives The sodium-potassium pump ( Na + /K + -ATP’ase), a membrane-bound sulfhydryl-containing integral membrane protein, is one of the targets of reactive oxygen species. The objective of this study was to assess the potential radioprotective effects of melatonin, amifostine and thymoquinone (TQ) on liver through Na + /K + ATP’ase enzyme activity in rats received total body irradiation (IR). Methods Thirty-eight adult rats were divided into 5 groups [ Group 1 (control group) : total body IR-only, Group 2 : IR-Melatonin (10 mg/kg), Group 3 : IR-TQ (10 mg/kg), Group 4 : IR-Amifostine (200 mg/kg), and Group 5 (sham group) : nothing]. Total body IR dose was 6 Gy. Melatonin, Amifostine and TQ were administered through intraperitoneal injection 30 min prior to IR. Tissue samples were taken 90 min following IR and Na + /K + -ATP’ase activity was measured in all groups. Results Rats receiving only IR showed lower liver Na + /K + -ATPase activity compared with the sham group (p=0.027). Enzyme activity was higher in the IR-Melatonin group compared with IR only group (p=0.087). Na + /K + -ATP’ase activity was also higher in the IR-TQ group compared with IR only group (p=0.013). The IR-Amifostine group showed increased enzyme activity compared with only IR group, although this difference was not statistically significant (p=0.524). Conclusions Melatonin and TQ administration before IR have protective effect on radiation-induced liver damage demonstrated through Na + /K + -ATP’ase enzyme activity that is highly sensitive to oxidative stress. This is the first study reporting the radioprotective effect of Melatonin and TQ on Na + /K + -ATP’ase activity.