Paradoxical morphometric and antioxidative effects of melatonin on vasospasm in experimental subarachnoid hemorrhage [Melatoninin deneysel subaraknoid kanama sonrası gelişen vazospazmda paradoksal morfometrik ve antioksidatif etkisi]

The purpose of this study is to investigate the histopathologic,biochemical and morphometric effects of melatonin on basilar artery and oxidative balances during subacute vasospasm following a subarachnoid hemorrhage (sah). twenty-four male wistar rats were used in the study. rats were divided randomly into 4 groups,six rats in each group: no sah (group i- control),only sah (group ii-control),sah plus melatonin 5mg/kg (group iii),and sah plus melatonin 10mg/kg (group iv). melatonin was administered intraperitoneally just after sah and repeated at 24th hour after as a second dose. animals were sacrificed 9 days after sah,and the basilar artery was harvested for morphometric and histopathologic studies. biochemical assays also were performed in terms of oxidant and antioxidant balance. in group iv area of lumen (al) was found to be increased suggesting vasodilation (p<0.05) compared to the controls. however,there was no significant difference between treated groups with melatonin in terms of al. no significant changes were observed in levels of total oxidant status (tos) between the groups,interestingly unexpected increases in tac levels were observed in “only sah group” compared to the treatment groups although group ii did not receive any treatment (p<0.05). the paradox between biochemical and morphometric changes may be explained by insufficient information on density and distribution of melatonin receptors in the brain parenchyma and vascular bed or by asynchronous happening of morphological and biochemical changes. © 2015,ege university press. all rights reserved.