Study Of The Effect On Vascular Endothelial Cells Injured By Organic Phosphorus

Objective: To examine whether organophosphorus(Org-P), an active component oforganophosphate, can directly cause injuries of vascular endothelial cells and toexplore the protective effects of captopril (Cap) on vascular endothelial cells damageinduced by Org-P and the potential mechanisms.Methods:(1) Rat isolated vascular rings experiment in vitro. Isolated rat aorticrings were prepared according to previous method. To explore the mechanisms ofendothelial cell damage induced by Org-P, the rings were respectively incubated withalone Org-P at the concentration of0.000363~36.3μmol/L, Org-P(3.63μmol/L)+catalase, Org-P(3.63μmol/L)+L-arginine, Org-P(3.63μmol/L)+atropine for0.5h.The ACh induced endothelium-dependent relaxation(EDR), sodiumnitroprusside(SNP) induced endothelium-independent relaxation and the vasculartissue biochemical reference were measured in rat vascular tissue. To explore themechanisms of protective effects of Cap on impaired vascular endothelial functioninduced by Org-P, the rings were respectively incubated with alone Cap(10μmol/L)and Org-P(3.63μmol/L), Cap(0.1,1,10μmol/L)+Org-P(3.63μmol/L),Org-P(3.63μmol/L)+CAT, Org-P(3.63μmol/L)+superoxide dismutase(SOD),Org-P(3.63μmol/L)+enalaprilat(Ena), Org-P(3.63μmol/L)+Cap(10μmol/L)+cystatin(PHMB) for0.5h. The ACh induced EDR, sodium nitroprusside (SNP)induced endothelium-independent relaxation and the vascular tissue biochemicalindex were measured in rat vascular tissues.(2) In cultured cell experimenrt in vitro.Cultured HUVEC were used to defect the endothelium cell monolayer permeabilityand the mechanisms of vascular endothelial cell damage induced by Org-P, theHUVEC were respectively incubated with Org-P(0.000363~36.3μmol/L),histamine(HA), Org-P(3.63μmol/L)+CAT for0.5h. HUVEC monolayer permeability, endothelial cell activity, biochemical index in cell cultured fluid and morphology ofthe endothelial cell were examined. To explore the protective effects of captopril onimpaired vascular endothelial function induced by Org-P, the HUVEC wererespectively incubated with alone Cap(10μmol/L), Org-P(3.63μmol/L), HA,Org-P(3.63μmol/L)+Cap(0.1,1,10μmol/L), Org-P(3.63μmol/L)+SOD,Org-P(3.63μmol/L)+CAT, Org-P(3.63μmol/L)+Ena, Org-P(3.63μmol/L)+Cap(10μmol/L)+PHMB for0.5h. HUVEC monolayer permeability, endothelial cellactivity, biochemical index in the cell cultured fluid and morphology of theendothelial cell were examined.Results:(1) Org-P(0.00363~36.3μmol/L) concentration and time-dependentlyinhibited ACh induced EDR, but did not affect SNP induced endothelium-independentrelaxation of aortic isolated rings. Org-P resulted in a reduction of both SOD activityand nitrite oxide (NO) content and increase of the malondialdehyde (MDA) content inthe vascular tissue. Cap(0.1~10μmol/L) concentration-dependently lessened theinhibition of ACh induced EDR injured by Org-P, but did not affect SNP inducedendothelium-independent relaxation of aortic rings. The preincubation Cap(10μmol/L)obviously lessened the inhibition of ACh induced EDR and protected againstreduction of both SOD activity and NO content and increase of the MDA content inthe vascular tissue induced by Org-P(3.63μmol/L). Org-P(0.00363~36.3μmol/L)concentration and time-dependently resulted in an increase of permeability of theendothelial monolayer and reduction of energy in cultured HUVEC. Org-P inducedmorphology changes of endothelial cell spaces. Org-P also resulted in a reduction ofboth SOD activity and NO content and increase of the MDA content in the cellcultured fluid. Cap(0.1~10μmol/L) concentration-dependently lessened the increasedof permeability of the endothelial monolayer induced by Org-P. The Cap(10μmol/L)obviously lessened the increase of vascular endothelial cell monolayer permeabilityand protected against reduction of energy and both SOD activity and NO content incultured HUVEC as well as increase of the MDA content in the cell cultured fluidinduced by Org-P. SOD and CAT have the analogic function as the Cap to protect the endothelial cell from being injured by Org-P. Ena cannot protect the vascularendothelial cells from being injured by Org-P, the effects of Cap could inhibited byPHMB, a sulfhydryl group blocking agent.Conclusion: Org-P could directly injure the function of vascular endothelium invitro and increase the endothelial cell monolayer permeability. The mechanisms ofOrg-P induced vascular endothelial injures may related to the oxidationstress-mediated reduction of NO release and formation of lipid peroxidation inducedby Org-P. The sulfhydryl (SH)-containing ACE inhibitors Cap can protect the vascularendothelium from being injured by Org-P and the mechanism may relate tononenzymatic antioxidant defenses.