Effect of erythropoietin on the oriented chemotaxis of bone-marrow mesenchymal stem cells under acute kidney injury microenvironment / 中华肾脏病杂志

ABSTRACT

Objective To investigate the migration of bone-marrow mesenchymal stem cells (BMSCs) under acute kidney injury (AKI) microenvironment in vitro and the effect of erythropoietin (EPO) intervention,and to explore its underlying mechanism.Methods Renal tubular epithelial cells (RTECs) were cultured in hypoxia/re-oxygenation (HR) condition for 12 h,respectively,in order to establish HR-RTEC.BMSCs and RTECs were co-cultured by Transwell system and were divided into 7 groupscontrol group (group①,only BMSC cultured),BMSC-RTEC co-culturing group (group ②),BMSC-HR-RTEC co-culturing + EPO intervention groups (group ③to group ⑦,EPO concentration0,1,5,10,50 IU/ml).All the groups were cultured for 48 h and the number of migrating BMSCs was detected.Western blotting was applied for the detection of SDF-1 expression in RTECs and pMAPK and MAPK levels in BMSCs.SDF-1 concentration in the RTECs culture supernatant was tested by ELISA.Results The number of BMSCs migrating to the low chamber where HR-RTECs were cultured was increased,and EPO intervention further enhanced this migration which reached the peak at the concentration of 10 IU/ml [Compared with group③,(46.67±7.37) cells vs (19.00±2.37) cells,P ＜ 0.05].Intracellular expression level and the secreated level of SDF-1 in HR-RTECs in group③ were higher than those in RTECs of group② [0.37±0.01 vs 0.19±0.01,P ＜ 0.05; (61.64±4.88) μg/L vs (35.26±8.78) μg/L,P ＜ 0.05].EPO intervention increased above SDF-1 levels and reached the peak at the concentration of 10 IU/ml [group⑥ vs group③(173.53± 14.66) μg/L vs (61.64±4.88) μg/L,P＜0.05],accompanied with enhanced phosphorylation of MAPK in BMSCs.Conclusions AKI microenvironment has obvious chemotaxis effect on BMSCs,and EPO intervention can strengthen this effect.The increased SDF-1 level and enhanced phosphorylation of MAPK,the downstream signal protein of SDF-1/CXCR4 axis,are the possible mechanism for EPO performance.