Type Ⅱ collagen as the carrier for xenogeneic chondrocyte transplantation for joint cartilage defect repair / 中国组织工程研究

ABSTRACT

BACKGROUND: Type Ⅱ collagen has been used as the carrier for chondrocyte transplantation in animal models, but whether type Ⅱ collagen may cause arthritis or mediate cytotoxicity remains unknown.OBJECTIVE: To detect the cellular immune functions of the New Zealand rabbits immunized by porcine type Ⅱ collagen.DESIGN: An exploratory comparative study based on the observations.SETTING: An institute of trauma surgery of a municipal hospital.MATERIALS: The study was conducted in the Institute of Trauma Surgery,Guangzhou Red Cross Hospital from August 1999 to February 2000. Six New Zealand rabbits, whose body mass ranged from 2.0 kg to 3.0 kg, were chosen of either gender.METHODS: The rabbits were immunized by porcine type Ⅱ collagen for 60days, during which the plasma was regularly taken for detection of type Ⅱ collagen antibody. On the 60th day, the peripheral blood as well as the spleens and lymph nodes were taken to separate the lymphocytes, which were subjected to secondary stimulation with type Ⅱ collagen in vitro to observe the reactive cell proliferation. The lymphocytes were randomly divided into two groups, and the first group was treated with phytohemagglutinin(PHA) of different concentrations to serve as the positive control, in which non-specific immunity was examined; The second group was treated with type Ⅱ collagen of different concentrations for examining specific immunity.peripheral blood lymphocytes of normal and immunized rabbits.RESULTS: On the 21st day, the titer of the antibody presented the first peak, and 40 days after the re-injection of the antigen the second peak appeared, which maintained for 20 days and then gradually descended. The lymphocytes of the normal rabbits proliferated in response to PHA stimulation but not to the first stimulation with the type Ⅱ collagen. The lymphocytes of the immunized rabbits exhibited significant proliferation upon stimulations with both PHA and type Ⅱ collagen. At the concentration of 25 mg/L, type Ⅱ collagen stimulation was sufficient to induce lymphocyte proliferation, the peak of which occurred when the collagen concentration reached 50 mg/L.CONCLUSION: Xenogenic type Ⅱ collagen at an adequate concentration may induce the increase of the type Ⅱ collagen antibody in immunized rabbits and proliferation of lymphocytes of the spleens and peripheral blood to cause cellular immune reaction and even immunological arthritis in relation to the transplantation.