Background: Tendon injury is a major orthopedic disorder. Ultrasound-targeted microbubble
destruction (UTMD) provides a promising method for gene transfection, which can be used for the
treatment of injured tendons.
Objective: The purpose of this study was to investigate the optimal transforming growth factor beta
(TGF-β) short hairpin RNA (shRNA) sequence and transfection conditions using UTMD in vitro and
to identify its ability for inhibiting the early adhesion repair of rats wounded achilles tendons in vivo.
Methods: The optimal sequence was selected analyzing under a fluorescence microscope and quantitative
real-time reverse transcription polymerase chain reaction in vitro. In vivo, 40 rats with wounded
Achilles tendons were divided into five groups: (1) control group, (2) plasmid group (3) plasmid + ultrasound
group, (4) plasmid + microbubble group, (5) plasmid + microbubble + ultrasound group, and
were euthanized at 14 days post treatment. TGF-β expression was evaluated using adhesion scores and
Results: The optimal condition for UTMD delivery in vitro was 1W/cm2 of output intensity and a 30%
duty cycle with 60 s irradiation time (P < 0.05). The transfection efficiency of the plasmid in group 5
was higher than that in other groups (P < 0.05). Moreover, the lowest adhesion index score and the
least expression of TGF-β were shown in group 5 (P < 0.05). When compared with the other groups,
group 5 had a milder inflammatory reaction.
Conclusion: The results suggested that UTMD delivery of TGF-β shRNA offers a promising treatment
approach for a tendon injury in vivo.