Abstract

To investigate the effect and its mechanism of oleuropein on the oxidative damage and apoptosis of astrocytes induced by oxygen-glucose deprivation, and its effect on circ_TTC3 and microRNA-138-5p. Astrocytes were divided into control group, oxygen-glucose deprivation group, oxygen-glucose deprivation+oleuropein 25 μmol/l, 50 μmol/l, 100 μmol/l groups, oxygen-glucose deprivation+si-negative control, si-circ_TTC3 group, oxygen-glucose deprivation+oleuropein+plasmid cloning deoxyribonucleic acid plasmid cloning deoxyribonucleic acid and plasmid cloning deoxyribonucleic acid-circ_TTC3 group. In comparison with the control group, the inhibiting rate of cell growth, apoptosis rate, malondialdehyde, lactate dehydrogenase levels and circ_TTC3 expression of astrocytes in the oxygen-glucose deprivation group were increased, while superoxide dismutase activity and miR-138-5p expression were declined (p<0.05). Compared to the oxygen-glucose deprivation group, the proliferative inhibiting rate, apoptosis rate, malondialdehyde, lactate dehydrogenase levels and circ_TTC3 expression of astrocytes in the oxygen-glucose deprivation+oleuropein 25 μmol/l group, oxygen-glucose deprivation+oleuropein 50 μmol/l group, and oxygen-glucose deprivation+oleuropein 100 μmol/l group were all weakened, superoxide dismutase activity and microRNA-138-5p expression were enhanced (p<0.05), and all were concentration-dependent. After silencing circ_TTC3, circ_TTC3 expression, malondialdehyde, lactate dehydrogenase levels, cell proliferation inhibition rate and apoptosis rate in astrocytes in the oxygen-glucose deprivation+si-circ_TTC3 group were all lower than those in oxygen-glucose deprivation+si-negative control group, while the superoxide dismutase activity was higher than that in oxygen-glucose deprivation+si-negative control group (p<0.05). Circ_TTC3 targeted and regulated microRNA-138-5p. Circ_TTC3 level, malondialdehyde and lactate dehydrogenase levels, cell proliferation inhibition rate, and apoptosis rate in astrocytes in the oxygen-glucose deprivation+oleuropein+ plasmid cloning deoxyribonucleic acid-circ_TTC3 group were all higher than those in oxygen-glucose deprivation+oleuropein+plasmid cloning deoxyribonucleic acid group, and there was a decrease of superoxide dismutase activity in the oxygen-glucose deprivation +oleuropein+plasmid cloning deoxyribonucleic acid-circ_TTC3 group compared with oxygen-glucose deprivation+oleuropein+plasmid cloning deoxyribonucleic acid group (p<0.05). Oleuropein could reduce oxidative stress and apoptosis, thereby protecting astrocytes from damage induced by oxygen-glucose deprivation by upregulating circ_TTC3 to target microRNA-138-5p.