Abstract: 【Abstract】Purpose To investigate the effect and mechanism of hypoxia on the expression of TGF-β1 and the proteins relating to endothelial-to-mesenchymal transition (EndMT) in rat glomerular endothelial cells (rGECs). Methods rGECs were cultured in a hypoxia incubator, and the cells were randomly divided into 5 groups according to hypoxia treatment time. Cell proliferation activity, the expression of TGF-β1 and EndMT related proteins were then measured in the 5 cell groups. RhoA/ROCK blocker and TGF-β1 receptor blocker were added to the hypoxia treated cells at appropriate time, and then the following indicators were assayed: ①TGF-β1 in cell culture medium; ②TGF-β1 and EndMT related proteins; ③change of RhoA/ROCK activity. Results ①The proliferative activity of rGECs increased with the prolongation of hypoxia treatment time with the biggest activity after hypoxia treatment for 72 hours (2.040±0.110, F=546.63, P＜0.001)；②Compared with the normoxic group, the expressions of TGF-β1 (F=16.320, P＜0.001) and α-SMA (F=5.032, P=0.009) in the hypoxic group increased significantly, while CD-31 protein (F=9.882, P＜0.001) decreased significantly. ③Under the hypoxic circumstances and treated with RhoA/ROCK blocker and TGF-β1 blocker, α-SMA protein decreased (relative amount from 1.423 to 0.750 and 0.434 respectively) and CD-31 protein increased (relative
amount from 0.741 to 0.779 and 0.934 respectively). Conclusion Hypoxia can increase cell proliferation and promote EndMT of rGECs. The use of TGF-β1 and RhoA/ROCK blockers under hypoxic conditions suggest that hypoxia environment promotes EndMT of rGECs via the TGF-β1-RhoA/ROCK signaling pathway.

Key words: Hypoxia, Rat glomerular endothelial cells, Endothelial-to-mesenchymal transition, TGF-β1-RhoA/ROCK signaling pathway