Minocycline exhibits synergism with conditioned medium of bone marrow mesenchymal stem cells against ischemic stroke

Several lines of evidence show that a conditioned medium of bone marrow mesenchymal stem cells (BM-MSCcm) improve functional recovery after ischemic stroke but do not reduce ischemic lesions. It is important to develop a treatment strategy that can exhibit a synergistic effect with BM-MSCcm against ischemic stroke. In this study, the effect of BM-MSCcm and/or minocycline was examined in culture and in a middle cerebral artery occlusion (MCAo) animal model. In neuron-glial cultures, BM-MSCcm and combined treatment, but not minocycline, effectively increased neuronal connection and oligodendroglial survival. In contrast, minocycline and combined treatment, but not BM-MSCcm, reduced toxin-induced free radical production in cultures. Either minocycline or BM-MSCcm, or in combination, conferred protective effects against oxygen glucose deprivation-induced cell damage. In an in vivo study, BM-MSCcm and minocycline were administered to rats 2 h after MCAo. Monotherapy with BM-MSCcm or minocycline after ischemic stroke resulted in 9.4% or 17.5% reduction in infarction volume, respectively, but there was no significant difference. Interestingly, there was a 33.9% significant reduction in infarction volume by combined treatment with BM-MSCcm and minocycline in an in vivo study. The combined therapy also significantly improved grasping power, which was not altered by monotherapy. Furthermore, combined therapy increased the expression of neuronal nuclei in the peri-infarct area and hippocampus, and concurrently decreased the expression of ED1 in rat brain and the peri-infarct zone. Our data suggest that minocycline exhibits a synergistic effect with BM-MSCcm against ischemic stroke not only to improve neurological functional outcome but also to reduce cerebral infarction.