Effects of MgSO4 on Cerebral Infarction after Permanent Middle Cerebral Artery Occlusion in Rat

ABSTRACT

OBJECTIVE: This study is aimed to prove the neuroprotective effect of magnesium ion, which is known to have competitive action against calcium influx in the process of neuronal damage. METHODS: One hundred twenty five male Sprague-Dawley rats weighing 300-350gm were divided into control and MgSO4 injected groups. Middle cerebral artery occlusion was induced by nylon insertion near internal carotid artery bifurcation via external carotid artery. Forty rats which were alive for 48 hours after the induction of cerebral infarction were drawn from each group. Thirty minutes after the induction of cerebral infarction, 750mumol/Kg of MgSO4 was intramuscullary injected for the experimental group and same amount of normal saline was injected for the control group. Each group was subdivided into groups of 20 rats 48 hours after the cerebral infarction. Brain-sections of a subgroup were obtained after transcardially perfusion of 2% 2', 3', 5'-triphenyl-tetrazolium chloride and infarction volume was measured using imaging analysis program. Brain-sections of the other subgroup were stained with terminal deoxynucleotidyl-transferase-mediated biotin dUTP nick end labeling(TUNEL) and apoptotic index(AI) was estimated. RESULTS: The volume of cerebral infarction of the control and MgSO4 injected groups were 52.44+/-5.68% and 38.38+/-9.02% respectively, and the infarction volume was significantly reduced in MgSO4 injected group(p<0.001). Brain edema volume were 209.01+/-75.41mm3 in control group and 140.7+/-81.89mm3 in MgSO4 injected group that was a significant reduction in MgSO4 injected group(p<0.001). AI of 53.68+/-6.38 for control group and 29.80+/-6.77 for MgSO4 injected group were estimated and MgSO4 injected groups showed a significant reduction(p<0.001). CONCLUSION: Magnesium ion has neuroprotective effect in reduction of cerebral infarction volume, brain edema volume and AI. In the future, various attempts to prove protecting mechanism of magnesium ion should be made and TUNEL stain is thought to be an effective comparison method in such studies.