Melatonin supplementation in rat ameliorates ovariectomy-induced oxidative stress

ABSTRACT

Objective The present study aims to determine the potential of melatonin supplementation in ameliorating tissue oxidative stress, elevated serum corticosterone and hepatic and renal dysfunction.

Materials and methods Adult Wistar rats, either ovariectomized or sham-operated, served as experimental or control groups, respectively. Rats received either melatonin, estrogen, progesterone or a combination of melatonin and estrogen for a period of 15 days. Tissue oxidative stress, serum markers of hepatic and renal dysfunction and serum corticosterone level formed the parameters of assay in all groups at the end of the treatment schedule.

Results Ovariectomized rats showed significant increases in levels of tissue lipid peroxidation, serum levels of glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, alkaline phosphatase, acid phosphatase and corticosterone and significant decrement in enzymatic and non-enzymatic antioxidant status. All parameters showed maximal reversal to control levels on supplementation with high-dose melatonin or estrogen + melatonin treatment.

Conclusion Melatonin supplementation proved better than estrogen replacement therapy, with the higher dose being more effective in preventing ovariectomy-induced increases in oxidative stress and serum levels of marker parameters of hepatic and renal dysfunction and corticosterone titer. Overall, melatonin supplementation therapy qualifies as a more potent and safe alternative to estrogen replacement therapy in alleviating postmenopausal increases in oxidative stress and hepatic and renal dysfunction.

Key words::

• melatonin
• oxidative stress
• corticosterone
• estrogen replacement therapy
• ovariectomy

ACKNOWLEDGEMENTS

Thanks are due to Professor T. G. Shrivastava, of the Immuno-Technology & Steroid Laboratory Department of Reproductive Biomedicine, NIHFW, Munirka, New Delhi, for the progesterone kit which was a generous gift from him and for his guidance throughout the work, and to Dr Sunil Shah, of Dr Sunil's Laboratory, Baroda for his valuable suggestions and help.

Conflict of interest The authors report no conflict of interest. The authors alone are responsible for the content and writing of this paper.

Source of funding B. D. B and P. K. S. acknowledge with thanks the fellowship from UGC under the UGCRFSMS scheme.