Synergistic efficacy of magnesium sulfate and FK506 on cerebral ischemia-induced infarct volume in gerbil.

In this study, we administered intraperitoneal magnesium sulfate (90 mg/kg), either alone or in combination with FK506 (0.5 mg/kg) in order to investigate the neuroprotective synergetic effects of both, 30 min before permanent occlusion of the middle cerebral artery (MCA) in gerbil.Postmortem infarct volume was determined by quantitative image analysis of triphenyltetrazolium-stained brain sections, collected at 1 h, 3 h and 24 h after initiation of cerebral ischemia, to measure consistent infarct volumes of the post -ischemic gerbil brain. Twenty-four male gerbils were intraperitoneally injected with MgSO4 (n=7), FK506 (n=8), or MgSO4 +FK506 (n=9), 30 min before permanent MCA occlusion. The brains of the treated groups were stained at 24 h after initiation of cerebral ischemia.Significant and consistent infarct volumes (78.3 +/- 3.6 mm3) were observed in the 24 H control group. The infarct volume in the MgSO4 + FK506 group was significantly reduced at each slice, compared to the untreated 24 H control group (P<0.05). Magnesium sulfate reduced total infarct volume by 25.4% (P<0.05), FK506 by 41% (P<0.05), and MgSO4 +FK506 by 50.5% (P<0.05). Also, the infarct volume (38.7 +/- 5.2 mm3) in the MgSO4 + FK506 group was the smallest in all the treated groups, near the volumes seen in the untreated 3H group.Acute administration of a combination of MgSO4 and FK506 has a synergetic efficacy against brain damage by permanent focal cerebral ischemia.