Effect of radix hedysari polysaccharide on human umbilical vein endothelial cells function induced by high glucose

Abstract

Objective To investigate effect of radix hedysari polysaccharide (HPS) on secretion of nitric oxide (NO) and endothelin-1 (ET-1) on human umbilical vein endothelial cells(HUVECs) induced by high glucose and its mechanism. Methods HUVECs were isolated from umbilical vein, and cultured cells were divided into normal control group, high glucose group, HPS group, MTT assay were used to analyze the effect of HPS on HUVECs viability under high glucose. The levels of NO, nitric oxide synthase (NOS) and inducible nitric oxide synthase (iNOS) were measured by colorimetric analysis. The content of ET-1 in clear supernatant were detected by enzyme linked immunosorbent assay (ELISA). The expression of endothelial nitric oxide synthase (eNOS), ET-1 mRNA, c-Jun kinase-1(JNK1) mRNA were examined by real-time quantitative RT-PCR. Results The cells viability were markedly decreased when HUVECs were treated with 30 mmol/L-glucose for 6 h((82.4±3.5)%), 24 h((68.2±1.4)%), 48 h((63.0±2.9)%), HPS could efficiently prevented cells viability lost(P<0.05), especially in 50 mg/L((85.3±4.6)%), 100 mg/L ((89.6±1.1)%), 200 mg/L ((88.8±3.6)%), P<0.05. In high glucose group, the levels of NO ((24.84±1.34)μmol/L)and NOS((0.54±0.06) U/ml) were increased at early stage and decreased at advanced stage compared with normal control group (P<0.05). The contents of iNOS((0.08±0.020) U/ml) and ET-1 ((0.710±0.030) ng/ml) were upgraded under high glucose at any time, nevertheless, HPS could balanced the levels of NO((23.20±0.55)μmol/L), NOS((0.46±0.10) U/ml), iNOS((0.08±0.020) U/ml) and ET-1((0.710±0.030) μg/L), P<0.05. At equal pace, the expressions of eNOS mRNA was up-regulated and ET-1 mRNA was down-regulated in HPS group compared with high glucose group(0.33±0.02 vs 0.23±0.04, 2.28±0.31 vs 2.79±0.29). The contents of JNK1 mRNA in HUVECs were shown to increased after exposure to high glucose(2.95±0.05), P<0.05, which were markedly prevented by HPS(1.45±0.05), P<0.05. Conclusion HPS can protect the injury of HUVECs induced by high glucose in vitro. The mechanism of protection may be associated with blocked JNK signaling pathway. Key words: Radix hedysari polysaccharide; Human umbilical vein endothelial cells; High glucose; Nitric oxide; Endothelin-1