Preparation of artificial biological ligament and its detection in vitro / 中国组织工程研究

ABSTRACT

BACKGROUND: Currently, the materials used in clinical practice to repair cruciate ligament of knee joint contain auto-graft bone- mid 1/3 patella tendon-bone (B-T-B), auto-semitendinous muscle, gracilis muscle and allogenic tissue graft. All of them are limited to a certain degree in clinical application. Therefore, people hope to consistently develop artificial ligaments to take the place of auto- and allografts. OBJECTIVE: To investigate the feasibility to construct artificial biological ligament (ABL) by applying a novel biochemical technique using porcine tendon as the raw material. DESIGN: Research of new biological material. SETTING: Department of Orthopedics, Third Affiliated Hospital of Sun Yat-sen University. MATERIALS Adult pigs of either gender were provided by the Animal Center of Sun Yat-sen University. Scanning electron microscope (SEM, S-520) was provided by Hitachi, Japan, and micro-controlled electron tension-testing device (Model LWK-10B) by Guangzhou Experimental Devices Factory. METHODS: The experiment was performed at the Animal Center of Sun Yat-sen University from January 2004 to June 2005. ABL was established by means of treating porcine tendon with epoxy cross-linking fixation, diversified antigen minimization process, mechanic enhancement modification and surface activating process. Under aseptic condition, a 6-month-old goat's bone marrow was abstracted, and then the bone marrow matrix stem cells were cultured in ABL stent for 3 weeks. Scanning electron microscope was used to observe structure and compatibility of artificial ligament, and mechanics test was used to analyze biomechanics characteristics of ABL. MAIN OUTCOME MEASURES: Structural features, cell compatibility and biomechanics characteristics of ABL.RESULTS: ① Structural features of ABL The appearance of ABL was similar to that of the normal human ligament. Histological examination showed that the ABL was collagen fibers with no cells. Electron microscope examination revealed that the ABL was composed of hair-looking and fiber-like objects running uniformly in a certain direction and closely parallel-arranged. ② Cell compatibility Three weeks after xenogenic marrow matrix cells were cultured on the surface of the ABL, it was noted that cells adhered and the matrix secreted by the cells precipitated around the cells. There were no cells found inside the ABL. ③ Mechanical strength of the ligament The average diameter of ABL was 5 mm and the mechanical test at a speed of 100 mm/min showed that its averaged tensile limit was 927.19 N and the tension-resistant strength was 47.22 N/mm those were close to the corresponding parameters of the normal goat's ACL. The normal goat's ACL was 5 mm. The greatest tensile load was 807.50 N and the tension-resistant strength was 41.13 N/mm.CONCLUSION:As we used the unique biochemical technique and minimized the xenogenic protein immunogenicity of the porcine tendon, ABL has acceptable biomechanical properties and superior biocompatibility. As a substitute of the ligament in the reconstruction of the ACL, ABL has a promising prospect in clinical applications.