ABSTRACT
Objective:To investigate the regulatory effects of endogenous nitric oxide (NO) on the activity of superoxide dismutase-1 (SOD1) and apoptosis of human umbilical vein endothelial cells (HUVECs).Methods:HUVECs were taken as the research object.The endothelial NO synthase (eNOS) short hairpin RNA(shRNA) lentivirus was employed to transfect HUVECs to knock down eNOS.HUVECs were divided in 4 groups: the scramble group, the eNOS shRNA group, the eNOS shRNA + sodium nitroprusside(SNP) group and the eNOS shRNA+ SNP+ tris (2-carboxyethyl) phosphine hydrochloride (TCEP) group.The protein expressions of eNOS and SOD1 dimer/monomer in cells were detected by western blot.The activity of SOD was detected by the enzyme-linked immunosorbent assay.The NO content in cells was detected with NO fluorescence probe.The level of superoxide anion in HUVECs was detected with dihydropyridine (DHE). The terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) assay was adopted to detect the apoptosis of HUVECs in situ.Results:Compared with the scramble group, the endogenous NO content (2.690±0.420 vs.15.029±2.193, P<0.01), eNOS protein expression (1.000±0.778 vs.3.141±0.199, P<0.01), SOD1 dimer/monomer ratio (4.6±1.0 vs.7.6±2.0, P<0.05) and SOD activity [(0.432±0.254) Carmen′s unit/10 4 cell vs.(1.000±0.116) Carmen′s unit/10 4 cell, P<0.01] were significantly decreased, while the level of intracellular superoxide anion (11.180±1.560 vs.6.146±1.007, P<0.01) and HUVECs apoptosis [75.0 (55.0, 100.0)% vs.0 (0, 0)%, P<0.01] were significantly increased in the eNOS shRNA group.Compared with the eNOS shRNA group, the content of endogenous NO (16.705±0.116 vs.2.690±0.420, P<0.01), the ratio of SOD1 dimer/monomer (7.3±2.0 vs.4.6±1.0, P<0.05) and the activity of SOD [(0.737±0.060) Carmen′s unit/10 4 cell vs.(0.432±0.254) Carmen′s unit/10 4 cell, P<0.05] were significantly increased, while the level of superoxide anion (6.897±1.648 vs.11.180±1.560, P<0.01) and the HUVECs apoptosis [0 (0, 0)% vs.75.0 (55.0, 100.0)%, P<0.01] were significantly decreased in the eNOS shRNA+ SNP group.Compared with the eNOS shRNA + SNP group, the ratio of SOD1 dimer/monomer (4.4±0.9 vs.7.3±2.0, P<0.05) and the activity of SOD [(0.214±0.084) Carmen′s unit/10 4 cell vs.(0.737±0.060) Carmen′s unit/10 4 cell, P<0.01] were significantly decreased, while the level of superoxide anion (10.917±1.552 vs.6.897±1.640, P<0.01) and the apoptosis level of HUVECs[63.6 (55.0, 90.0)% vs.0 (0, 0)%, P<0.01] were significantly increased in the eNOS shRNA+ SNP+ TCEP group.However, there was no significant difference in the NO content (16.112±0.926 vs.16.705±0.116, P>0.05). Conclusions:Endogenous NO could effectively antagonize the apoptosis of endothelial cells by increasing the cysteine-dependent SOD1 dimer/monomer ratio, enhancing SOD activity and inhibiting the accumulation of reactive oxygen species.
ABSTRACT
Abstrac:Aim To study the effect of hydroxysafflor yellow A ( HYSA ) on the proliferation of vascular smooth muscle cells ( VSMCs) and the related molecu-lar mechanism. Methods The inhibitory effects of hydroxysafflor yellow A on VSMC proliferation was de-tected using cell culture, MTT assay, Western blot and immunohistochemical staining. Results The results showed that HYSA inhibited cell proliferation induced by PDGF in a dose-dependent (5,10,20,40 μmol· L-1 ) manner, reduced proliferating cell nuclear anti-gen ( PCNA ) expression and blocked PDGFR-MEK-ERK1/2 signaling pathway activated by PDGF in VSMCs. Conclusion HYSA inhibits VSMCs prolifer-ation via reducing the expression of PCNA and blocking signal transduction of MEK-ERK1/2 in VSMCs.