Adenovirus-mediated gene transfer to healing tendon - enhanced efficiency using a gelatin sponge

Adenovirus-mediated gene transfer is a potential method for enhancing tendon healing. We investigated the transfection of Ad5CMVntLacZ, an adenovirus containing the reporter gene LacZ, in primary cultured human rotator cuff tendon cells and in a rat Achilles tendon healing model in vivo. Ad5CMVempty, the adenoviral vector containing no inserted gene, was used as a control for adenoviral transfection alone. Activity of beta-galactosidase,the protein expressed by LacZ gene, was measured using a beta-galactosidase assay and detected visually by X-gal staining. Cultured cells were successfully transfected without impairing cell viability. Maximal beta-galactosidase activity was detected when cells were transfected at the dose of 1000 PFU/cell. The duration of LacZ expression was six days with a peak value at 24 h post-transfection. A transfection rate of 100% was obtained at 5000 PFU/cell. Successful in vivo transfection by Ad5CMVntLacZ was obtained in healing rat Achilles tendon as confirmed by X-gal staining. 0.4% of tendon cells were transfected when Ad5CMVntLacZ was injected into the tendon at a dose of 10(6) PFU. The rate rose to 2% with 10(8) PFU and 3% with 10(9) PFU. The duration of LacZ expression in vivo was 17 days. Transfection efficiency was enhanced threefold and localization improved when a gelatin sponge was used to deliver the adenovirus. The results demonstrate that adenovirus can be used to deliver a gene of interest to cultured human rotator cuff tendon cells and healing tendon, with gelatin sponge implantation enhancing adenoviral transfection efficiency in vivo. (C) 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.