Zinc supplementation results in improved therapeutic potential of bone marrow-derived mesenchymal stromal cells in a mouse ischemic limb model

Background aims. We wanted to determine whether zinc supplementation can inhibit bone marrow-derived mesenchymal stromal cell (MSC) apoptosis and enhance their tissue regenerative potential a in mouse ischemic hindlimb model. Methods. Rat bone marrow cells were cultured and the resulting MSC were passaged for 3-7 generations. The proliferation and apoptosis of MSC was examined by 3[4,5-dimethy1-2-thiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry analysis. The activation of protein kinases B (Akt) was determined by Western blots. Vascular endothelial growth factor (VEGF) levels were examined by enzyme-linked immunosorbent assay. The mouse hindlimb ischemic model was established by ligating the right femoral artery. Mice received MSC, zinc-treated MSC or vehicle. The blood flow was assessed by laser Doppler imaging. The survival rate of donor cells was quantified by real-time polymerase chain reaction for the sex-determining region of the Y-chromosome (Sry). Angiogenesis was assessed by histochemical staining and immunofluoresence staining. Results. Supplementation with physiologic amounts of zinc caused a marked attenuation of cell apoptosis, enhanced cell viabilities, increased VEGF release and up-regulated Akt activation. Zinc-treated MSC delivered into ischemic hindlimbs resulted in significant improvements in limb blood perfusion by increased implanted MSC survival and stimulated angiogenesis. Conclusions. This study demonstrates the potential of zinc supplement to enhance survival of engrafted MSC and ameliorate their tissue regenerative potential in a mouse ischemic hindlimb model.