ObjectiveTo 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. MethodsAdTGF-β1 and AdGFP were diluted to 5×108 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. ResultsGreen 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). ConclusionHamstring tendon transfected with AdTGF-β1 gene can promote the healing of tendon-bone interface after ACL reconstruction.
ObjectiveTo detect the expression of human transforming growth factor β1 (hTGF-β1) gene mediated by adenovirus (Ad) in hamstring tendon after anterior cruciate ligament (ACL) reconstruction in rabbits. MethodsAd-hTGF-β1 and Ad-green fluorescent protein (GFP) were diluted to 5×108 PFU/mL with DMEM. Forty-eight New Zealand white rabbits were divided into 3 groups randomly (n=16) for ACL reconstruction with hamstring tendon autograft. Hamstring tendon was cultured and transfected with Ad-hTGF-β1 (group A) and Ad-GFP (group B) for 12 hours before ACL reconstruction, and was cultured with DMEM in group C. After 12 hours of transfection, green fluorescence was observed in groups A and B under fluorescence microscopy. At 2, 4, 6, and 8 weeks after operation, the hamstring tendon was harvested to detect the mRNA and protein expressions of hTGF-β1 by real time fluorescence quantitative PCR and Western blot. ResultsGreen 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 hTGF-β1 mRNA expression could be detected in group A, but it could not be detected in group B and group C. The mRNA expression levels of hTGF-β1 were 1.004±0.072 at 2 weeks, 0.785±0.038 at 4 weeks, 0.469±0.053 at 6 weeks, and 0.172±0.021 at 8 weeks in group A, showing significant difference (P<0.05). Western blot results showed weakly positive band in groups B and C; the protein expression of TGF-β1 in group A was significantly higher than that in groups B and C (P<0.05), but no significant difference was found between groups B and C P>0.05). The protein expression of TGF-β1 gradually reduced with time, showing significant difference between different time points (P<0.05). ConclusionAd-hTGF-β1 can transfect the hamstring tendon successfully, and it can effectively express for a long time after ACL reconstruction.