The Role And Mechanism Of Resveratrol Pretreated Mesenchymal Stem Cell In Acute Kidney Injury

Objective Acute kidney injury(AKI)is a frequent clinical syndrome with high morbidity and high mortality.However,the clinical therapy strategies for AKI are not effective.Although a number of studies showed that mesenchymal stem cells(MSC)can alleviate AKI,the efficacy of MSC-based therapy can be further improved.In this study,we investigated that whether resveratrol-modified huc MSC(RES-huc MSC)can show a more efficient repairing ability than did huc MSC in kidney injury.Meanwhile,we analyzed its potential mechanism.Methods The concentration and working time of RES treating huc MSC were determined by a real-time cellular analysis system and MTT assay.We established cisplatin-induced AKI rat models,then DMSO-and RES-huc MSC were transplanted via tail vein.We compared the differences between DMSO-huc MSC and RES-huc MSC on the repair effect of kidney injury through collecting blood samples to measure Cr and BUN levels,and collecting kidney tissues to do H&E staining,injury score,Western blot,immunohistochemistry staining and TUNEL assay.Rat renal tubular epithelial cell line NRK-52 E was used to do experiments in vitro.After treatment with cisplatin,NRK-52 E cells co-cultured with DMSO-/RES-huc MSC.Flow cytometry,Western blot,immunohistochemistry staining and TUNEL assay were used to evaluate the apoptosis of NRK-52 E cells.The proliferation and apoptosis effect of RES on huc MSC was respectively tested by colony-forming assay and Western blot.When looking for the potential mechanism of RES treatment on huc MSC,we used q RT-PCR to select a most obvious change factor(PDGF-DD)in huc MSC after treatment with RES.Meanwhile,the protein levels of downstream ERK pathway were detected by Western blot.Then,si RNA was transfected into huc MSC to knock down PDGF-DD.Western blot and colony-forming assay were carried out to confirm the effect of PDGF-DD on RES-huc MSC.We further verified the therapeutic effect of PDGF-DD on RES-huc MSC in AKI rat models.In addition,we collected the conditioned mediums(Cd M)of DMSO-/RES-huc MSC and observe their effects on HUVEC cells migration and proliferation ability.Immunofluorescence staining assay tested the expression of CD31 in kidney tissues.Then,we analyzed the role of PDGF-DD in angiogenesis via si RNA interference experiment.Results A real-time cellular analysis system and MTT assay showed that the concentration and working time of RES treating huc MSC were 20mmol/L,12 h.RES-huc MSC exerted a better repairing effect than huc MSC in cisplatin-induced AKI rat models,as demonstrated by the decrease of serum Cr and BUN levels,preservation of the integrity of the tubules,the decrease of histological injury score,as well as fewer protein casts and apoptotic kidney tubular cells.Similarly,Res-huc MSCs could significantly inhibit cisplatin-induced NRK-52 E cells apoptosis compared with huc MSC.Effects of RES treatment on huc MSC include inhibiting huc MSC apoptosis and promoting huc MSC proliferation.When looking for the potential mechanism of RES treatment on huc MSC,we found that RES increased the level of PDGF-DD in huc MSC.Meanwhile,RES increased the expression of PDGFR-b in huc MSC and activated ERK pathway.In contrast,PDGF-DD knockdown decreased the expression of PDGFR-b in RES-huc MSC,correlating with inhibiting ERK pathway,which increased the level of apoptosis-associated proteins in RES-huc MSC and weakened the colony formation ability of RES-huc MSC.Furthermore,compared with huc MSC,RES-huc MSC increased the levels of PDGF-DD and PDGFR-b in kidney tissues,which resulted in downstream phosphorylation of ERK.However,PDGF-DD knockdown impaired the renal protection of RES-huc MSC.In addition,the Cd M of RES-huc MSC enhanced the HUVEC cells migration and proliferation ability compared with the Cd M of DMSO-huc MSC.Meanwhile,immunofluorescence staining assay showed that the CD31 expression highly increased in the RES-huc MSC group compared with that in the DMSO-huc MSC group in vivo.Nevertheless,the angiogenesis was abrogated when RES-huc MSC was treated with PDGF-DD si RNA.Conclusion our findings showed that resveratrol-modified huc MSC activated ERK pathway in renal tubular cells and promoted angiogenesis in endothelial cells via paracrine PDGF-DD,which could be a novel strategy for enhancing the therapy efficacy of huc MSC in cisplatin-induced kidney injury.