[EFFECT OF HAMSTRING TENDON TRANSFECTED WITH ADENOVIRUS- MEDIATED TRANSFORMING GROWTH FACTOR β₁ GENE ON HISTOMORPHOLOGY OF TENDON-BONE INTERFACE HEALING AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION IN RABBITS]

Abstract

Objective: To investigate the effect of hamstring tendon transfected with adenovirus-mediated transforming growth factor β₁ (AdTGF-β₁) genes on the histomorphology of tendon-bone interface healing after anterior cruciate ligament (ACL) reconstruction in rabbits.

Methods: AdTGF-β₁ and AdGFP were diluted to 5 x 10⁸ PFU/mL with DMEM. Forty-eight New Zealand white rabbits were divided into 3 groups randomly (n=16), weighing 1.6-2.5 kg for ACL reconstruction with hamstring tendon autograft. Hamstring tendon was cultured and transfected with AdTGF-β₁ (group A) and AdGFP (group B) for 12 hours before ACL reconstruction, and was cultured with DMEM in group C. After 12 hours of transfection, the expression of green fluorescence was observed in groups A and B under fluorescence microscopy; TGF-β₁ protein level was detected by ELISA in group A. At 2, 4, 8, and 12 weeks after operation, the specimens were harvested for HE and Masson staining; the number of fibroblasts was counted, and the Buark grading was used to evaluate tendon-bone interface healing.

Results: Green fluorescence was observed after 12 hours of transfection in groups A and B. TGF-β₁ protein level reached (221.0 ± 12.2) ng/mL at 12 hours in group A. The histological observation showed that few fibroblasts and collagen fibers were found, and Sharpey fibers appeared in group A; regular Sharpey fibers were seen in the interface, and integrity interface in some areas at 12 weeks. But fibroblasts of groups B and C were less than those of group A, with loose tendon-bone interface; no integrity interface was observed at 12 weeks. The number of fibroblasts and Buark grading of group A were significantly higher than those of groups B and C (P < 0.05), but no significant difference was found between groups B and C (P > 0.05).

Conclusion: Hamstring tendon transfected with AdTGF-β₁ gene can promote the healing of tendon-bone interface after ACL reconstruction.