Figure 1: The experimental protocol. Four weeks after diabetes onset induced by STZ (60 mg/Kg), rats presented mild microalbuminuria (DN rats) and divided into PBS group (PBS infusion), UTMD group (ultrasound + microbubble), MSCs group ( eGFP labeled MSCs for infusion), and UTMD + MSCs group (MSCs infusion combined with ultrasound and microbubble), and a group of normal nondiabetic rats (no treatment) was set as a normal control group. Random blood glucose concentrations were measured at 1, 2, 4, and 8 weeks, and determination of plasma insulin, UAER, histology, immunofluorescence, immunohistochemistry, ELISA, and Western blot were performed 8 weeks after MSCs treatment. To track the intrarenal localization of implanted MSCs and explore the underlying mechanism, DN rats which received ultrasonic irradiation with or without eGFP-labeled MSCs infusion were killed 3 days after treatment, and laser scanning confocal microscope (LSCM), Real-Time PCR, and transmission electron microscopy were performed.