SRGN and atrial fibrillation: H&E, Safranin-O, and Sirius red (taken in bright field and polarized light) staining showed that the amount of NP tissue and disc height in the Srgn−/− plus AF puncture group surpassed those in the WT plus AF puncture group and the histological scores of the WT plus AF puncture group were higher than those of the Srgn−/− plus AF puncture group (Fig. 3f, h).