OBJECTIVETo investigate the effect of thrombopoietin (TPO) on chemical hypoxia-induced apoptosis of human umbilical vein endothelial cells (HUVEC), and to explore its potential mechanism.

METHODSThe experiment was divided into 4 groups. The untreated HUVECs were used as normal control group. HUVECs treated with CoCl was CoCl group, and TPO was added into the culture medium 48 h before CoCl treatment as TPO + CoCl group. The cells was treated with TPO alone as TPO group. The cell viability and apoptosis of each groups were tested by Cell Counter Kit 8 (CCK-8) assay and flow cytometry. The expression of Caspase-3 and mitochondrial membrane potential (MMP) were then determined by flow cytometry with Caspase-3-PE and JC-1. The effect of TPO in PI3K/AKT pathway was detected by using Western blot.

RESULTSCoCl significantly inhibited the growth of HUVECs. The cell viability of HUVECs decreased gradually with enhancement of CoCl at a gradient of chemical concentrations (r= -0.997). CoCl dramatically increased apoptosis of HUVECs, whereas pre-treatment with TPO rescued cell apoptosis induced by CoCl (P<0.001). Further investigation found that TPO decreased the expression of Caspase-3 and inhibited the reduction of MMP induced by CoCl (P<0.05). TPO could increased the activation of PI3K/AKT pathway in HUVECs.

CONCLUSIONTPO has a protective effect against CoCl-induced apoptosis of HUVECs through activating the PI3K/AKT pathway, thus decreasing the expression of apoptosis protease Caspase-3 and inhibiting the reduction of MMP.