The aim of the present study was to explore whether ultrasound microbubble destruction augments site-targeted engraftment of bone marrow mesenchymal stem cells (BM-MSCs) to kidney tissue and promotes recovery of the kidney in acute kidney injury (AKI) in rats. AKI was induced by the subcutaneous injection of mercuric chloride (HgCl₂). Forty Sprague-Dawley (SD) rats were randomly divided into the following groups after the establishment of rat models of AKI (n = 10): (1) Model group alone (control group); (2) 1.0 W/cm² ultrasound (US) + microbubble (MB) (US/MB group); (3) MSCs group; and (4) 1.0 W/cm² US+MB + MSCs group (US/MB + MSCs group). The number of 4',6-diamidino-2-phenylindole (DAPI) labelled MSCs was evaluated by fluorescence microscopy and real-time polymerase chain reaction (RT-PCR) and Western blotting and histological examination were performed 7 days after MSCs transplantation. It was observed via fluorescence microscopy that the number of DAPI-labelled MSCs in the kidney for the US/MB + MSCs group was significantly more than the MSCs group (p < 0.05). The results from RT-PCR revealed that the US/MB and US/MB + MSCs groups markedly increased the level of inter-cellular adhesion molecule 1 (ICAM-1) messenger ribonucleic acid (mRNA) compared with the control group and the MSCs group (p < 0.05). Western blot analysis showed that the expression of hepatocyte growth factor (HGF) and epidermal growth factor (EGF) in the US/MB + MSCs group were markedly increased compared with the all other groups (p < 0.01). The extent of tubular necrosis and dilation was significantly milder in the US/MB + MSCs group (acoustic exposure conditions: 5s at 1 MHz and 1.0 W/cm² with a 5s pause, totalling 60 s) than the all other groups (p < 0.05). Microbubble destruction by 1.0 W/cm² ultrasound can promote both the homing of BM-MSCs to kidney tissue and the recovery of the kidney in AKI in rats.
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