In consistent with in vitro results, we also observed that intravitreal injection of MSC-sEV reversed hyperglycemia caused the activation of PTEN and increased p-AKT level in retinal tissues of diabetic rats (Fig. 4C, D), suggesting that PTEN/AKT signaling may be involved in the MSC-sEV-mediated protection against DR. Here, PTEN is linked to Hyperglycemia.