Mesenchymal stem cell-conditioned medium prevents radiation-induced liver injury by inhibiting inflammation and protecting sinusoidal endothelial cells

Current management of radiation-induced liver injury is limited. sinusoidal endothelial cell (sec) apoptosis and inflammation are considered to be initiating events in hepatic damage. we hypothesized that mesenchymal stem cells (mscs) possess anti-apoptotic and anti-inflammatory actions during hepatic irradiation,acting via paracrine mechanisms. this study aims to examine whether msc-derived bioactive components are protective against radiationinduced liver injury in rats. msc-conditioned medium (msc-cm) was generated from rat bone marrow-derived mscs. the effect of msc-cm on the viability of irradiated secs was examined by flow cytometric analysis. activation of the akt and erk pathways was analyzed by western blot. msc-cm was also delivered to sprague-dawley rats immediately before receiving liver irradiation,followed by testing for pathological features,changes in serum hyaluronic acid,alt,and inflammatory cytokine levels,and liver cell apoptosis. msc-cm enhanced the viability of irradiated secs in vitro and induced akt and erk phosphorylation in these cells. infusion of msc-cm immediately before liver irradiation provided a significant anti-apoptotic effect on secs and improved the histopathological features of injury in the irradiated liver. msc-cm also reduced the secretion and expression of inflammatory cytokines and increased the expression of anti-inflammatory cytokines. msc-derived bioactive components could be a novel therapeutic approach for treating radiation-induced liver injury. © the author 2015.