We also measured CLDN1 protein level by immunostaining in IECs and found a pattern consistent with its mRNA level, indicating that STZ‐HSCT/STZ/↑Sod2 treatment reverses, while CTL‐HSCT/CTL/shSod2 treatment mimics, maternal diabetes–mediated CLDN1 suppression in IECs (Fig. 4E and F). This evidence concerns the gene CLDN1 and diabetes mellitus.