Synergic effect of combined cyclosporin and melatonin protects the brain against acute ischemic reperfusion injury

Background: This study tested whether combined cyclosporin-A (CsA) and melatonin (Mel) was superior to either one on protecting the brain against ischemia (occluded left-middle-cerebral-artery for 90-min)-reperfusion (for 14 days) injury. Methods and results: Neuro-2a cells (N2a) were categorized into groups 1 (N2a), 2 (N2a-IR), 3 (N2a-IR-Mel), 4 (N2a-IR-CsA) and 5 (N2a-IR-CsA-Mel). in vitro results showed the protein expressions of cytosolic-cytochrome-C/mitochondrial-Bax/cleaved-capase-3/NOX-1/NOX-2 and flow-cytometric results of ROS (DCFDA/Mito-SOX) were highest in group 2, lowest in group 1, significantly lower in group 5 than in groups 3/4, but they showed no difference in groups 3/4 (all p < 0.001). Male-adult-SD rats (50) were equally categorized into groups 1 (sham-operated-control), 2 (IR), 3 (IR-CsA/20.0 mg/kg at 0.5/24/48 h intraperitoneally after IR), 4 (IR-Mel/50.0 mg/kg intraperitoneally at 30 min and 30 mg/kg at 6/24/48 h after IR) and 5 (IR-CsA-Mel). The brain-infarct-area (BIA) (at day-3 by TTC-stain) was lowest in group 1, highest in group 2, significantly lower in group 5 than groups 3/4, but it showed no difference between groups 3/4 whereas the brain-infarct-volume (at day 14 by MRI) was similar as BIA except for significantly lower in group 4 than in group 3 (all p < 0.0001). By day 14, microscopic finding showed the numbers of glial+/GFAP+/AQP + cells expressed an identical trend whereas the number of NeuN + cells exhibited an opposite pattern of BIA among the groups (all p < 0.0001). The protein expressions of oxidative-stress (NOX-1/NOX-2/p22phox/oxidized-protein), inflammatory (TNF-α/p-NF-κB/MMP-9), apoptotic (mitochondrial-Bax/caspase-3/PARP) and mitochondrial-damaged (Cyclophilin-D/DRP1/cytosolic-cytochrome-C) biomarkers displayed an identical pattern of BIA among the five groups (all p < 0.0001). Conclusion: Combined CsA-Mel was superior to either CsA or Mel on protecting the brain against IR injury.