Calycosin Alleviates Oxidative Injury in Spinal Astrocytes by Regulating the GP130/JAK/STAT Pathway

Abstract

Spinal injury is a complicated disease and is reported to be associated with damages on spinal astrocytes induced by oxidative injury. Astragali Radi, a famous traditional Chinese medicine, is reported to have promising efficacy in protecting injuries in the central nervous system. This study aims to investigate the effect of calycosin, an isoflavone phytoestrogens isolated from Astragali Radi, on oxidative injury in spinal astrocytes induced by H2O2 and the underlying mechanism. Primary rat spinal astrocytes were pretreated with 5, 10, and 20 μM calycosin and subjected to H2O2 treatment for 24 h to establish an oxidative injury model. Cell viability was detected using the CCK-8 assay to screen the optimized concentration of calycosin. Flow cytometry was used to evaluate the apoptotic rate and cell cycle. The expression level of Brdu was visualized using the immunofluorescence assay. Western blotting was used to measure the expression levels of p-JAK2, p-STAT3, p-AKT, GP130, and IL-6 in spinal astrocytes. We found that proliferation was inhibited and that apoptosis was induced by the stimulation of H2O2. The expression levels of p-JAK2, p-STAT3, p-AKT, GP130, and IL-6 were significantly elevated in H2O2-treated astrocytes. After the treatment of calycosin, proliferation was facilitated, and apoptosis was suppressed. These phenomena were accompanied by the downregulation of p-JAK2, p-STAT3, p-AKT, GP130, and IL-6, which were abolished by the co-administration of PI3K (ly294002) or STAT3 (stattic) inhibitor. Overall, calycosin alleviated oxidative injury in spinal astrocytes by mediating the GP130/JAK/STAT pathway.