The effects of prophylactic zinc and melatonin application on experimental spinal cord ischemia-reperfusion injury in rabbits: Experimental study

Study design: Experimental study. Objectives: To determine the neuroprotective effects of zinc and melatonin on spinal cord ischemia-reperfusion (I/R) injuries of rabbits. Setting: The Experimental Research Centre of Selçuk University, Konya, Turkey. Methods: Twenty-four male rabbits underwent spinal cord ischemia by clamping the thoraco-abdominal aorta for 20 min. Twenty minutes before the aortic clamping, animals received zinc, melatonin or a combination of both. Neurological examination of the animals was performed three times during reperfusion period. The animals were killed 24 h after reperfusion. Spinal cord samples were taken for biochemical and histopathological evaluation. Results: Pre-treated animals with zinc, melatonin or combination displayed better neurological outcomes than the I/R group (P<0.05). Zinc, melatonin and combined treatment prevented spinal cord injury by reducing apoptosis rate (P<0.05) and preserving intact ganglion cell numbers (P<0.05). Zinc pre-treatment protected spinal cord by preventing malondialdehyde (MDA) formation (P=0.002), increasing glutathione peroxidase (GPx) activity (P=0.002) and decreasing xanthine oxidase enzyme activity (P=0.026) at molecular level. Melatonin treatment also resulted with MDA formation (P=0.002), increased GPx activity (P=0.002) and decreased xanthine oxidase activity (P=0.026). Conclusion: The results of the study showed that prophylactic zinc and melatonin use in spinal cord I/R not only suppressed lipid peroxidation by activating antioxidant systems but also had significant neuroprotective effects by specifically improving the neurological and histopathological situation. © 2007 International Spinal Cord Society All rights reserved.