To test this, we first investigated the changes of LCN2 protein expression and secretion in astrocytes using a well-established in vitro ischemia model (3 h oxygen/glucose deprivation (OGD)/ 24 h reoxygenation (OGD/R)) with or without the NHE1 inhibitor HOE642 (Fig. 4A). Here, LCN2 is linked to ischemia.