Effect of exogenous melatonin on X-ray induced cellular toxicity in lymphatic tissue of Indian tropical male squirrel, Funambulus pennanti.
OBJECTIVE
The radioprotective ability of melatonin was investigated in the Indian tropical rodent, Funambulus pennanti during its reproductively inactive phase (RIP) when peripheral melatonin is high and the animal is under the influence of environmental stresses.


METHODS
Fifty male squirrels were divided into two sets of 25 each; with set 1 receiving 0.9% saline and set 2 receiving 25 mug melatonin/100 g body weight/day for four weeks during evening hours. Five saline-treated and five-melatonin treated squirrels were sacrificed at times of 4, 24, 48 and 72 hours following 2.06 Gy X-ray radiation. Remaining squirrels that were not exposed to X-ray were used as control and melatonin treated, respectively. Total leukocyte count (TLC) and lymphocyte count (LC) in peripheral blood and lipid peroxidation (LPO) status, superoxide dismutase (SOD) activity, total antioxidant status (TAS), apoptotic percentage on the basis of morphological changes and DNA fragmentation and caspase-3 activity were measured in the spleens of squirrels.


RESULTS
Peripheral blood and spleens with higher intrinsic levels of environmental and X-radiation induced free radical generation had inhibited TLC, LC, SOD activity and TAS and increased LPO and apoptosis. Melatonin pre-treatment significantly reduced and altered the changes brought on by X-radiation.


CONCLUSIONS
Exogenous melatonin with its anti-apoptotic and antioxidant properties additively increased the immunity of the squirrels, by protecting their hematopoietic system and lymphoid organs against X-ray radiation induced cellular toxicity.
Sharma
Shweta
S
Pineal Research Laboratory, Department of Zoology, Banaras Hindu University, Varanasi.
Haldar
Chandana
C
Chaube
Shail K
SK
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis; D005609:Free Radicals; D006412:Hematopoietic Stem Cells / Q000528:radiation effects; D007962:Leukocytes / Q000166:cytology* / Q000378:metabolism; D015227:Lipid Peroxidation; D008214:Lymphocytes / Q000378:metabolism; D008221:Lymphoid Tissue / Q000528:radiation effects*; D008297:Male; D008550:Melatonin / Q000378:metabolism* / Q000494:pharmacology*; D018384:Oxidative Stress; D012589:Sciuridae; D013154:Spleen / Q000378:metabolism / Q000528:radiation effects; D014965:X-Rays
D000975:Antioxidants; D005609:Free Radicals; D008550:Melatonin