Effects Of Hypoxia On The Expression And Secretion Of Renalase In Human Proximal Renal Tubular Epithelial Cell

Objective To explore whether hypoxia can affect the expression and secretion of renalase in human proximal renal tubular cells(HK-2 cells).Methods The frozen HK-2 cells were recovered. Passages 2-5 cells were used for the experiment after twenty-four hours cell synchronization in serum-free DMEM.A sealed cell culture vessel was used to induced hypoxia in our experiment. the HK-2 cells were cultured under hypoxia or normal oxygen for different times. The morphological changes were observed by inverted microscope. Realtime-PCR and Western blot were done to detect the expression and secretion of renalase in vivo. All data were analyzed using SPSS statistical analysis software.Results 1.Morphological alterations:Compared with normoxia group,hypoxia obviously inhibited HK-2 cells growth, cell number reduced to 80% of normoxia in 48 h.2.Changes of The renalase protein content in supernatant: The renalase protein content in supernatant is lower than the minimum detection limit 0.0625μg/ml after hypoxia.3.Changes of the mRNA expression of renalase:The mRNA expression of renalase after hypoxia for 6hs was not significantly change(P>0.05)as compared with that of the control group(1.25±0.41).However, level of renalase after 12h and 24h hypoxia were significantly increased(P<0.05,P<0.01)(1.96±0.33,3.50±0.60). But after hypoxia 24h the mRNA expression of renalase is decreased(1.92±0.01), the difference was not significant compared with that of control groups (P > 0.05).4.Changes of the expression of renalase protein :Changes of expression level of renalase protein in HK-2 cells after hypoxia were similar with mRNA change, increase first, decrease then. Conclusion Compared with normoxia, the mRNA and protein expression of renalase in HK-2 cells after hypoxia show a first gradually increased then decreased trend.