Abstract
This study was designed to study the effects of the potential radioprotective properties of pharmacological doses of melatonin against organ damage induced by whole-body irradiation (IR) in rats.
A total of 32 male Sprague-Dawley rats were exposed to irradiation performed with a LINAC producing 6 MV photons at a focus 100 cm distant from the skin.
Under ketamine anaesthesia, each rat received a single whole-body dose of 800 cGy.
Immediately before and after IR, rats were treated with either saline or melatonin (20 mg/kg and 10 mg/kg, i.p.) and decapitated at 12-h after exposure to irradiation.
Another group of rats was followed for 72-h after IR, where melatonin (10 mg/kg, i.p.) injections were repeated once daily.
Tissue levels of malondialdehyde (MDA)--an index of lipid peroxidation--, glutathione (GSH)--a key to antioxidant--and myeloperoxidase (MPO) activity--an index of neutrophil infiltration--were estimated in liver, lung, colon and intestinal tissues.
The results demonstrate that both 12-h and 72-h following IR, tissue levels of MDA were elevated (p<0.05-0.001), while GSH levels were reduced (p<0.05-0.001) in all organs.
On the other hand, melatonin, reduced the levels of MDA and increased the GSH levels significantly, (p<0.05-0.001). MPO activity was increased significantly in the colonic tissue at the both 12-h and 72-h, and in the hepatic tissue at the 72-h following IR, which were reduced by melatonin (p<0.01-0.001). In the lung tissue enzyme activity was decreased at 72nd h of post-irradiation.
In conclusion, the increase in MDA levels and MPO activity and the concomitant decrease in GSH levels demonstrate the role of oxidative mechanisms in irradiation-induced tissue damage, and melatonin, by its free radical scavenging and antioxidant properties, ameliorates irradiation-induced organ injury.
Thus, supplementing cancer patients with adjuvant therapy of melatonin may have some benefit for successful radiotherapy.
See also:
- The Di Bella Method (A Fixed Part - Melatonin tablets);
- Solution of retinoids in vitamin E in the Di Bella Method biological multitherapy;
- All-Trans-Retinoic Acid (ATRA - analogues and/or derivatives);
- The Di Bella Method (A Fixed Part - All-Trans Retinoic Acid, Analogues and/or Derivatives);
- The Di Bella Method (A Fixed Part - Alpha tocopheryl acetate/Vitamin E);
- Oesophageal squamocellular carcinoma: a complete and objective response;
- Complete objective response to biological therapy of plurifocal breast carcinoma.