Relationship between endothelial damage and p120-catenin in paraquat intoxication and the protective effect of mangiferin / 中华危重病急救医学

ABSTRACT

Objective To investigate the relationship between endothelial damage and p120-catenin (p120-ctn) in a model of paraquat intoxication,and the modulatory effect of mangiferin on p120-ctn.Methods Human umbilical vein endothelial cells (HUVECs) were cultured in two compartment spreading apparatus in vitro.The endothelial cells were divided into three groupscontrol group (cultured in DMEM with 10％ fetal bovine serum),paraquat group (paraquat was added to the medium with final concentration of 0.05 μmol/L) and mangiferin group (cultured in medium with addition of paraquat for 30 minutes,then mangiferin was added in a final concentration of 20 μmol/L).The cellular permeability at 6,12,24,48,72 hours after culture in the three groups was measured.The expressions of p120-ctn 1A,p120-ctn 3A mRNA and p120-ctn protein were measured by reverse transcription-polymerase chain reaction (RT-PCR) and Western Blot analysis.The distribution of p120-ctn protein was observed by immunofluorescence.Results Compared with control group,cellular permeability in paraquat and mangiferin groups were increased with prolongation of time,and peaked at 72 hours [(29.86 ± 3.98)％,(24.39 ± 2.79)％ vs.(11.71 ± 1.67)％,both P＜0.05].The cellular permeability was significantly lower in mangiferin group than that in paraquat group at different time points (all P＜0.05).At 6 hours after intoxication,the expressions of p120-ctn 1A,p 120-ctn 3A mRNA (gray value) and p 120-ctn protein (gray value) were significantly lower in paraquat group than those in control group (p120-ctn 1A mRNA0.150 ± 0.024 vs.0.433 ± 0.024,p120-ctn 3A mRNA0.316 ± 0.043 vs.0.701 ±0.020,p120-ctn protein0.485 ±0.031 vs.0.763 ±0.038,all P＜0.01).The expressions of p120-ctn 1A,p120-ctn 3A mRNA and p120-ctn protein were significantly higher in mangiferin group than those in paraquat group from 6 hours on (p120-ctn 1A mRNA0.281 ± 0.021 vs.0.150 ± 0.024,p120-ctn 3A mRNA0.602 ± 0.042 vs.0.316 ± 0.043,p120-ctn protein0.675 ± 0.031 vs.0.485 ± 0.031,all P＜0.01),and they were gradually increased with prolongation of time,and peaked at 72 hours (p120-ctn 1A mRNA1.376 ±0.128 vs.0.150 ± 0.024,p120-ctn 3A mRNA1.251 ± 0.059 vs.0.316 ± 0.043,p120-ctn protein0.844 ± 0.050 vs.0.485 ± 0.031,all P＜ 0.01).Under upright fluorescence microscope,p120-ctn was mainly distributed in the cell membrane in control group,with a slight expression in cytoplasm,and no expression in the nuclei.With prolongation of time,p120-ctn expression in the cell membrane was gradually decreased in paraquat group,while it was increased in the cytoplasm and nuclei,with blurring of cell membrane and widening of cellular gap.p120-ctn expression was improved on the cell membrane in mangiferin group at corresponding time points,with decreased in expression in nuclei and cytoplasm.Conclusion The p120-ctn protein plays an important role in the enhancement of endothelial permeability in paraquat intoxication,and mangiferin may attenuate endothelial injury in paraquat intoxication possibly through modulation of p 120-ctn protein.