Objective    To explore the efficacy and safety of ultrasonic microbubbles to enhance the transfection of adenoviral vector encoding multidrug-resistance gene 1 (MDR1) into rabbit bone marrow mononuclear cells.     Methods    Adenoviral vector Ad5-MDR1 encoding MDR1 gene were prepared and titrated. Bone marrow mononuclear cells were isolated and collected from rabbit bone marrow

and divided into 5 groups (4.0×10

6

to 5.0×10

6

cells in each group) in a 6-well pla

te

conventional culture group (A)

Ad5-MDR1 group (B); Ad5-MDR1+ultrasound group (C)

Ad5-MDR1+microbubbles group (D) and Ad5-MDR1+microbubbles+ultrasound group (E). MDR1 gene was transferred into the cells with or without ultrasound wave irradiation (665 kHz

0.5 W/cm

2

15 s)

and cocultured with ultrasonic microbubbles and/or adenoviral vector. The expression of MDR1 gene in the mononuclear cells

the positive transfection rate and the P-gp function were tested by RT-PCR

and daunorubicin (DNR) efflux testing with flow cytometry. The cell cycle of the mononuclear cells after transfection was tested by flow cytometry.     Results    The Ad5-MDR1 vector with high titer was obtained

and ultrasonic microbubbles were prepared. RT-PCR showed the specific electrophoresis strips were at 194 bp in 4 groups except group A

indicating that the foreign MDR1 gene had been transferred successfully into the cells mediated by adenovirus. The optical density of the strip from group E was higher than that in group B

C and D (P0.05). DNR efflux testing confirmed that the P-gp of transferred MDR1 gene maintained its biological function

and the function of P-gp in group E was higher than that in other groups (P0.05). The cell cycles of transferred mononuclear cells did not be affected by the gene transfection.     Conclusion    The transfer of foreign MDR1 gene into rabbit mononuclear cells with adenovirus vector is enhanced by the ultrasonic microbubbles

with safety and availability.