Investigation On The Effect Of H₂S Against Apoptosis Induced By OxHDL In Human Umbilical Vein Endothelial Cells And Its Preliminary Mechanisms

OBJECTIVE:To investigate the effect of exogenous H2S on HUVECs apoptosis induced byoxHDL and its preliminary mechanism.METHODS:1. Different concentrations (100,200,300mg/L)of high density lipoprotein(oxHDL) incubates with human umbilical vein endothelial cells (HUVECs) atdifferent time, the blank group and300mg/L HDL group for24h as controls.Hoechst33258fluorescent staining was used to detecte nuclear morphology, four methylthiazolyl tetrazolium (MTT) was used to detecte cell survival rate, LDH concentrationwas tested by microplate reader, to choose best oxHDL concentration in inducingHUVECs apoptosis.2. With different concentrations (50,100,200μ mol/L) of NaHSpretreatment with HUVECs for24h, then adding a concentration of300mg/L ofoxHDL, blank group as controls. Hoechst33258fluorescent staining was used todetecte nuclear morphology, four methyl thiazolyl tetrazolium (MTT) was used todetecte cell survival rate, LDH concentration was tested by microplate reader.3. With different concentrations (50,100,200μ mol/L) of NaHS andSB203580(p38MAPK inhibitor,20μmol/L) pretreatment with HUVECs for24h,then adding a concentration of300mg/L of oxHDL. RT-PCR and Western Blot wasused to study expression of caspase-3, Bcl-2, and p-p38MAPK expression. RESULTS:1. With the incresement of time and concentration, apoptotic cells increasesignificantly compared with normal control group and HDL group，cell viabilitydecreases significantly, release of LDH increases significantly，the difference isstatistically significant (P<0.05)；2. NaHS could inhibit these effects induced byoxHDL, the inhibit effect is the most obviously in200μmol/L, the difference isstatistically significant (P<0.05).3. NaHS could partially inhibit upregulation ofcaspase-3expression and downregulation of Bcl-2expression induced by oxHDLwith concentration increments, the difference is statistically significant (P<0.05).4.p38MAPK phosphorylation(p-p38) level increases significantly while treatment withoxHDL, however, pretreatment of NaHS could decrease p-p38MAPK level inducedby oxHDL (P<0.05).CONCLUSION:H2S could significantly inhibit HUVECs apoptosis induced by oxHDL, thiseffect may be related to upregulation of Bcl-2expression,downregulation of Caspase-3and p-p38MAPK expression.