Iomechanics And Imaging Studies Of Adenovirus-mediated Gene Transfer TGFβ1 Hamstring Tendon Autograft ACL Reconstruction Of The Rabbit

【Objective】ACL(Anterior Cruciate Ligament, ACL) plays a very important role in stabilizing knee whose injury is one of the most common in knee sports injuries. Due to the poor ability of self healing after anterior cruciate ligament ruptured, currently transplantation reconstruct is the primary means of clinically treatment of anterior cruciate ligament injuries. ACL reconstruction surgery, autologous free multi-stand Hamstring is the one of the most commonly used autograft transplantation with the best biomechanical properties. Early healing is an important condition to protect ultimate function and efficacy of ligament reconstruction. Traditionally clinical Hamstring tendon transplant also can bring a range of issue such as the healing time being too long but this deficiency can be overcome by using cytokine transforming growth factor β1(TGF- β1). In this study, we reconstruct rabbit ACL by using adenovirus-mediated gene transfer TGFβ1. Through the study of postoperative graft biomechanics, we explore the impact of TGFβ1 gene transfection on the reconstruct ion of anterior cruciate ligament injury.【Methods】Before operation, we build recombinant adenovirus vector Adh TGFβ1 which carries h TGFβ1. 48 New Zealand white rabbits with weight 2.0 ± 0.4 kg and average age of 2-month-old are randomly divided into A, B, and C group, each group of size 16. Rabbit double hind side of knee is our research object and autologous Hamstring tendon is ACL grafts. A group reconstructs ACL using autologous ipsilateral transfected h TGFβ1 of Hamstring tendon, namely Ad TGFβ1 transfection group(experimental group); group B group reconstruct ACL using ipsilateral transfected with empty vector adenovirus Hamstring tendon reconstruction Ad GFP ACL, namely Ad GFP transfected group( empty vector control group); Group C reconstruct ACL using ipsilateral Hamstring tendon autograft, the DMEM-treated group(control group).The surgery is strictly aseptic and we give anti-infection treatment after operation. Four rabbits were sacrificed in each group at four different time points of two weeks, four weeks, eight weeks, and twelve weeks after starting the experiment to observe the general appearance of the graph. In addition, we scanned shift and edge detection of bone mineral density and bone tunnel diameter tunnel using three-dimensional CT, recorded load- displacement curve, calculated the maximum load and stiffness using software, documented the failure point is attached to the Ministry of the femoral bone tunnel, embryo bone tunnel ligament attached to the Ministry or Department of the intermediate. The experimental data were statistically analyzed to compare the imaging and biomechanical properties after reconstructing ACL in three groups at different time points.【Results】1.General form of AnatomySubjects were grown in good condition,and good functional recovery of knee reconstruction. All were negative in knee drawer test and lachnman test.Three groups of rabbits, respectively, after 2 weeks, 4 weeks, 8 weeks, 12 weeks of the four time points to observe the slaughter 4, no significant swelling around the knee appears incision good, no infection and dehiscence occurs, intra-articular synovial hyperplasia, meniscus good, no obvious fracture, anterior cruciate ligament laxity obviously no time, two weeks when the top of the femur Road colloid gap still visible presence at four weeks of the femoral and tibial bone tunnel mouth showing a small amount of scar tissue and bone tissue, a lot of scar tissue occurs eight weeks, the bone tunnel outside the mouth of a small amount of bone tissue, bone tunnel at 12 weeks are more visible outside the mouth of osteoid tissue transplanted tendon adhesions and the tunnel wall.2.CT imaging observationDifferences between each set of data after 2 weeks there was not statistically significant(P> 0.05). In 4 weeks, 8 weeks, 12 weeks, the degree of expansion of the experimental group was significantly lower than the bone tunnel empty vector control group and the control group, but bone mineral density and bone tunnel tunnel edge of the experimental group is higher BMD empty vector control group and the control group(P <0.05), the difference between the empty vector control group and the control group was not statistically significant(P> 0.05).3.BiomechanicsAfter 2 weeks, 4 weeks, tendon grafts were removed from the bone tunnel, but at the same time points the pull strength in group A is larger then in group B and C. 8 weeks after surgery there are two cases of group A in the central tendon graft ruptured. After 12 weeks, the control group had one case of tendon graft removed from the bone tunnel, the rest of the tendon grafts are central fault; after the first 2 weeks, 4 weeks, 8 weeks, 12 weeks in the experimental group tendon graft maximum load was significantly higher than the control group, there was a significant statistical difference(P <0.05); after 2 weeks, 4 weeks, 8 weeks, 12 weeks in the experimental group tendon graft stiffness significantly increased compared with the control group, there was a significant statistical difference(P <0.05).【Conclusion】Adenovirus-mediated gene transfer TGFβ1 can bring a positive impact of Hamstring tendon autograft on anterior cruciate ligament reconstruction surgery for rabbit by maintaining the stability of the knee. Compared to the traditional autologous Hamstring tendon grafts, adenovirus-mediated gene transfer TGFβ1 can promote bone healing of Hamstring tendon autograft ACL reconstruction. In anterior cruciate ligament reconstruction surgery, it can provide more early strong tensile strength, so that the knee better access to early rehabilitation.