[Protective effect of notoginsenoside R1 on neuron injury induced by OGD/R through ATF6/Akt signaling pathway]

Notoginsenoside R1(NGR1),a critical compound in traditional herb Panax notoginseng, is a kind of estrogen receptor agonist.It is reported to exhibit anti-apoptotic,anti-oxidative and anti-inflammatory properties activity, so it is widely used for treatment of various diseases.In order to investigate the potential neuroprotective effect of NGR1 in hypoxic-ischemic brain damage(HIBD), primary cortical neurons were used in this study to establish oxygen-glucose deprivation/reoxygenation(OGD/R) injury models. They were treated with NGR1 and estrogen receptor inhibitor ICI-182780 respectively, then the neuronal survival, cell membrane integrity and apoptosis were assessed by MTT assay,lactate dehydrogenase test(LDH) and Hoechst 33342 stain respectively, while the protein expression levels of ATF6α,p-Akt,Akt,Bax and Cleaved Caspase-3 were measured by Western blotting. Results indicated that as compared with the blank control group,OGD/R could induce cell injury and apoptosis(P<0.05), reduce relative integrity of cell membrane(P<0.05), decrease protein expression of ATF6α,p-Akt(P<0.05), and increase protein expression of Bax and Cleaved Caspase-3(P<0.05) in the primary cortical cells. After NGR1 treatment, the expression levels of ATF6α,p-Akt were obviously increased, and the expression levels of Bax and Cleaved Caspase-3 and the apoptosis of neuron were decreased(P<0.05). However, these neuroprotective properties of NGR1 against ODG/R-induced cell damage could be blocked by ICI-182780. This finding indicated that NGR1 may protect the primary cortical neurons against OGD/R induced injury,and the mechanism may be associated with accelerating the activation of the ATF6/Akt signaling pathway via estrogen receptors.