OBJECTIVE This experimental study was aim to investigate the osteogenesis of ceramic-like xenogeneic bone (CXB) combining with bone marrow (BM). METHODS The CXB combining BM was implanted into the sacrospinalis muscle of rabbits, and CXB implanted alone was used as control. Eighteen Japanese rabbits with long ear were used. The size of CXB was 5 mm x 5 mm x 5 mm, and the implanted materials were taken out at 2, 4, 8, 12, 16 and 24 weeks after implantation. The histological and histochemical characteristics were investigated. RESULTS There existed cartilage and new bone in the groups of CXB combining BM in 2 weeks. Later, be cartilage turned out to the bone and in eight weeks the medullary cavity appeared. However, as the time went on, new bone formation increased and typical osteogenesis could be found. While in the groups of CXB alone, no formation of new bone or cartilage was found. CONCLUSION The implantation of CXB combined with BM could result in new bone formation in the way of osteoconduation, osteoinduction, and providing, osteoblasts or chondroblasts. It could be an ideal bone substitute, and its clinical use in future seemed very hopeful.
This paper reviewed the main achievements in the research on tissue engineering tendon, focusing on major problems concerning the substitute for extracellular matrix (ECM) of tendon, biological characteristics of tendon cells, and tendon cells compounding with ECM substitute. It was concluded the important problems in the study of the tissue engineering having specific reparative functions could be: to prepare the ECM materials suitable for the tendon cells to attach, grow, and function; to establish the tendon cell line whose growth, proliferation, and immunological antigenicity could be modulated and controlled, and simulating the mechanical environment of tendon in vivo, to adopt three-dimensional tendon cell culture method.
Abstract A new type of artificial material could possibly be produced by combination of osteoblast with bioactive material in culture, and thus, make the material "alive" . To study the behavior of osteoblast cultured with bioactive materials, the osteoblasts were isolated from the periosteum of Newzeland Rabbits tibia, and cultured in RPMI1640 medium. After 13 subcultures, the cells were identified as osteoblast in vitro by electron microscope, AKP activity and detection of mineral deposition ability. The osteoblasts were subcultured with three bioactive materials: bioactive glass ceramics (BGC), hydroxyapatite (HA), and double phase hydroxyapatite (HA/TCP). After incubationfor 48 hours, scan electron microscope, 3H-TDR, XRD, RS and EDXAwere performed. The results showed that the osteoblasts grew on the HA/TCR had a higher proliferation rate and better osteoblastoid shape than those grew on BCG and HA. Themechanism of the growth of osteoblasts on bioactive materials was discussed, and the factors influencing the growth of osteoblast were analyzed.
Limitation of donor source for allograft makes the research on xenograft progress. Pig is regarded as one of the ideal donor animals. The major obstacle in xenograft is hyperacute rejection, which is caused by complements after they are activated by xenogeneic antigens combined with natural antibodies. It has been confirmed that alpha-Gal is the major target antigen, whose expression is incharged by alpha-1,3 galactosyltransferase (alpha-GT). The approaches to overcome hyperacute rejection against alpha-Gal included: immunoadsorption of xenogeneic natural antibodies, lysis of antigen by enzyme and genetic manupilation to obtain animal lack of alpha-GT. Besides alpha-Gal, there were other antigens binding to human serum antibody, such as gp65 and gp100, which was expressed on PAEC after induced by TNF, the A-like antigen. But their function was still unknown. It was debatable on the role of MHC in xenograft. Both direct and indirect pathway were involved in cellular response in xenograft.
It was reported that the systemic use of phenytoin could promote healing of fracture. In order to observe the effect of local application of phenytoin in the healing of fracture, the experiment was performed. Seventy-two rabbits were divided into three groups. Fractures were created on both radius of all rabbits. Group 1, intraperitoneal injection of phenytoin with a dosage of 50 mg/kg per day; Group 2, local use of phenytoin with a dosage of 40 mg/kg was injected in the fracture site every seventy-two hours, and Group 3, injection mormal saline of in the control group. Eight rabbits in each group were sacrificed in the 9th, 16th and 30th days after operation respectively. By X-ray excuiualtion, the healing of fracture was observed. Dry and wet weights of the callus were determined. After HE and Mallory’s stain, the samples were examined under microscope. Results showed that both local and systemic use of phenytoin promoted healing of fracture. The effects of phenytoin in the two groups were the same and had no significant difference.
From 1987, in 4 cases having muscle damage associated with extensive skin defeet, the repair was carried out by anastomosing the neurovascular pedicle of the free latissimus dorsi myocutaneous graft with the host. The patients were followed up from 6 months to 3 years. The muscle power of the injured part following repair had returned to about 4 degrees, and the external appearance and the function were satisfactory. The advantages and disadvantages of this operation, the preparation of the recipient area and the management of the tendon were discussed.