Mesenchymal Stem Cell-conditioned Medium Attenuated CoCl2-induced Injury of Renal Tubular Epithelial Cells by Inhibiting NCOA1, HIF-1α, and Sox9

Backgrounds: Renal interstitial fibrosis (RIF) constitutes the ultimate pathological alteration in nearly all chronic kidney diseases (CKD). Mesenchymal stem cell conditioned medium (MSC-CM) exhibits an alleviating impact on renal fibrosis; however, the underlying mechanism remains unclear. The objective of this study was to explore whether MSC-CM regulates the expression of α-smooth muscle actin (α-SMA), Transforming growth factor-β1 (TGF-β1), Hypoxia-inducible factor-1α (HIF-1α), Nuclear receptor coactivators (NCOA1), and SRY-related high mobility (Sox9). Methods: Rat renal tubular epithelial cells (RTECs), NRK-52E, were treated with diverse concentrations of Cobalt chloride (CoCl2) for 24 hours. The survival rate and protein expression of NRK-52E cells exposed to different concentrations of CoCl2 were determined to identify the final concentration. Three groups of NRK-52E cells were employed in the experiment: the normal control group, the 400 μM CoCl2 group, and the MSC-CM + 400 μM CoCl2 group. The cell morphology was observed by an inverted phase contrast microscope and scanning electron microscope, and the protein expressions of α-SMA, TGF-β1, HIF-1α, NCOA1, and Sox9 were detected. Result: The microscopic findings demonstrated that MSC-CM was able to decrease the degree of cytochemical hypoxia damage in NRK-52E cells induced by CoCl2. Immunofluorescence and Western blot analyses also affirmed a similar tendency. The upregulation of α-SMA, TGF-β1, HIF-1α, NCOA1, and Sox9 triggered by CoCl2 could be inhibited following MSC-CM intervention. Conclusion: Our findings indicate that MSC-CM exerts a protective effect on RTECs by down-regulating α-SMA, TGF-β1, HIF-1α, NCOA1, and Sox9.