Protective effects of Astragaloside IV against oxidative injury and apoptosis in cultured astrocytes by regulating Nrf2/JNK signaling

Ischemic stroke is a worldwide complex brain disease that results in numerous disabilities and deaths. It leads to the deprivation of oxygen and glucose, which causes energy failure and neuronal death. The activation of astrocytes contributes to neuronal damage or repair after brain ischemia/reperfusion, although astrocytes get little attention as potential drug targets. This study investigated the protective effects of Astragaloside IV (AS-IV) on oxygen glucose deprivation/reoxygenation (OGD/R)-induced damage in rat primary cultured astrocytes and the underlying molecular mechanism. The results showed that compared with the control group, astrocytes under OGD/R exposure significantly decreased cell viability and increased the number of apoptotic cells, whereas AS-IV evidently protected the astrocytes against OGD/R-induced cell damage. In addition, low and medium concentrations of AS-IV can promote the increase of intracellular superoxide dismutase (SOD) level, as well as restored the morphological changes caused by OGD/R exposure. Supplementation with AS-IV after OGD/R exposure promoted the expression of oxidation and apoptosis indexes and further study demonstrated that AS-IV inhibited CXCR4 receptor and downregulated the activation of p-JNK/JNK pathway, which suppressed the expression of Bax/Bcl-2, and finally uprising Nrf2/Keap1 signaling. In conclusion, these findings revealed that AS-IV protected against OGD/R-induced astrocytes through inhibiting oxidative stress and apoptotic pathways.