Enhanced homing of bone-marrow derived mesenchymal stem cells on rabbit myocardial ischemia by intravenous injection of mesenchymal stem cells under the mediation of diagnostic ultrasound and microbubbles

Objective To explore the targeting homing capacity of bone-marrow derived mesenchymal stem eells(MSCs) on rabbit myocardial ischemia by intravenous injection of MSCs under the mediation of diagnostic ultrasound and microbubble. Methods Density gradient centrifugation and adherent culture method were used in the isolation and cultivation of MSCs. MSCs were labeled with DAPI. Rabbit myocardial infarction(MI) models were builded by totally ligation of left anterior descending branch of coronary artery. DAPI labeled MSCs were implanted by intravenous injection with or without the mediation of diagnostic ultrasound and microbubbles. Forty-eight hours after cell transplantation, the hearts of MI rabbits were made of frozen section and observed under fluorescent microscope. The DAPI positive cells were counted in the MI and border area of rabbit heart and compared between two groups. Pathological changes of MI area were observed with HE staining under light microscope and transmission electronic microscope. Results The number of DAPI positive cells in MI and border area of rabbit in both groups were counted under fluorescent microscope. There were more DAPI positive cells in the MI area in ultrasound + microbubble + MSCs group (213.2±26.5) than that in the intravenous injection group (146.8±18.78, P<0.01). There were erythrocytes leaking out of the vessels in MI area in HE staining section under light microscope in ultrasound + microbubble + MSCs group while there were nearly none in the intravenous injection MSCs group. The intercellular space of endothelial cells of the vessels wall was increased and serum component leaked out of the vessel wall in ultrasound + microbubble + MSCs under transmission electronic microscope. Conclusions The targeted homing capacity of BM-MSCs in the MI area of rabbit heart can be enhanced under the mediation of diagnostic ultrasound and microbubbles. Key words: Ultrasonography;  Microbubbles;  Mesenehymal stem cell transplantation;  Myocardialischemia