The Mechenism Research Of Human Wharton’s Jelly Mesechymal Stromal Cell Derived Mircro-vesicles Alleviate Acute And Chronic Kidney Injury Induced By Ischemia-reperfusion Injury In Rats

OBJECTIVE To investigate whether micro-vesicles derived from human Wharton-Jelly mesenchymal stromal cells could protect against ischemia reperfusion induced acute and chronic kidney injury, and to explore the potential mechanisms.METHODS The mesenchymal stromal cells were isolated from human umbilical cord and cultured. The conditioned medium was harvested after 24-hour serum-free hunger for 3-6 passages MSCs. MVs were isolated from CM suing differential centrifugation and measured by protein concentration. 8-weeks old adult SD rats were separated into three groups(shame group, experimental group and control group), and were performed by unilateral ischemia-reperfusion injury for left kidney. 100 μg MVs were delivered from tail vein in experimental group while the same volume of vehicles(M199) were administrated in control group. The animals were sacrificed at 24 h, 48 h and 2 weeks after reperfusion respectively and the left kidney and blood were harvested. The H&E staining for renal tissues slides were used for histological assess and scoring for renal injury. The ROS level in kidney tissues was measured by DCFH-DA method. MDA concentration in renal tissues, 8-OHdg immune-staining for kidney tissue slides and Oxyblot method were enrolled for assessing the oxidative stress. TUNEL staining and Ki67 immune-staining were used to detect cell apoptosis and cell proliferation respectively. The renal fibrosis was assessed by Masson’s trichrome staining and α-SMA expression. After the rat’s right uninjured kidney was removed on day 12, the blood samples were obtained for measurement of plasma BUN and creatinine to assess the kidney function. The expression of NOX2 was assayed by Western-blot and immunohistochemistry methods. In vitro, NRK-52 E and HUVEC cells were injured by hypoxia for 6 hours. After incubated with MVs or vehicle for 48 hours, the NOX2 expression was assessed by Western-blot and Immunofluorescence staining.RESULTS The expression of NOX2 and reactive oxygen species(ROS) in injured kidney tissues was declined and the oxidative stress was alleviated in MVs group at 24 h and 48 h in parallel with the reduced apoptosis and enhanced proliferation of cells. IRI-initiated fibrosis was abrogated by MVs coincident with renal function amelioration at 2 weeks. NOX2 was also found down-regulated by MVs both in HUVEC and NRK-52 E cell line under hypoxia injury model in vitro.CONLUSION A single administration of h WJMSC-MVs might protect the kidney by alleviation of the oxidative stress in the early stage of kidney IRI through suppressing NOX2 expression. Moreover, it could reduce the fibrosis and improved renal function.BACKGROUND The endocrine/paracrine mechanisms have been paid more attention in the mesenchymal stromal cells(MSCs) therapy for acute kidney injury(AKI) now. Here we systematically reviewed the therapeutic role of MSCs conditioned medium(CM) or MSCs released extracellular- vesicles(Evs) for AKI in rodent model.METHODS Studies were searched from Pubmed and Scopus databases using our search strategy and screened by our eligibility criteria. The information of serum Creatinine(Scr) concentration, CM or Evs, measurement time point, AKI model and other parameters were extracted. Pooled analysis and subgroup analysis as well as multivariable Meta-regression were performed. Heterogeneity and publication bias were also investigated.RESULTS There were 13 studies in total included and analyzed. The pooled analysis showed elevated Scr reduction(0.93 [1.20, 0.67], mg/d L) in rodent models of AKI after CM/Evs therapy. From subgroup analysis, Evs showed more therapeutic effects than CM(P = 0.05). There were also other significant influential factors for Scr reduction including measurement time point(P = 0.0004) and therapeutic time point(P < 0.0001). While other parameters such as deliver route, injury type and cell type, were not significant influential factors. Multivariable Meta-regression analysis showed that measurement time point(P = 0.041), therapeutic time point(P=0.03), Evs or CM(P = 0.0003) and cell type(P < 0.0001) were the origin of the heterogeneity.CONCLUSION The present Meta-analysis confirmed that CM or Evs derived from MSCs could rescue the impaired renal-function in AKI. Compared with CM, Evs might play more therapeutic role in recovery from renal failure. In addition, CM or Evs administration in early stage of AKI might get more obvious effects.