Immunogenicity of osteoblasts prior to and after liquid nitrogen cryopreservation / 中国组织工程研究

ABSTRACT

BACKGROUND: Cryopreservation can decrease tissue and organ immunogenicity. The effects of cryopreservation on cell immunogenicity are disputed.OBJECTIVE: To investigate the effects of liquid nitrogen cryopreservation on osteoblast immunogenicity. DESIGN: Randomized,controlled ,paired-sample experiment. SETTING: This study was performed in the Laboratory Center, Qilu Hospital Affiliated to Shandong University between July 2003 and March 2004. MATERIALS Four New Zealand rabbits of either gender were included for this study. 3H-TdR was provided by Nuclear Medicine Institute of Shandong University. METHODS: Osteoblasts were cultured from the tibial periosteum of New Zealand rabbits and then cryopreservated in the liquid nitrogen for 3 months and defrosted. Cryopreservated and thawn osteoblasts were set as cryopreserved group and freshly cultured osteoblasts were set as non-cyropreserved group. Major histocompatibility complex (MHC)-I positive rate was examined by flow cytometry assay prior to and after cryopreservation. Simultaneously, mixed lymphocyte-osteoblast cultures were established. Lymphocyte stimulation index was calculated after counting the flares using β liquid scintilloscope. MAIN OUTCOME MEASURES: MHI-I antigen positive rate and lymphocyte stimulation index prior to and after cryopreservation of osteoblasts. RESULTS: MHI-I antigen positive rate and lymphocyte stimulation index of osteoblasts was significantly higher in the non-cryopreserved group than in the cryopreserved group (P＜0.01). CONCLUSION: The immunogenicity of cryopreserved osteoblasts was significantly decreased. Liquid nitrogen cryopreservation is an ideal method to decrease the immunogenicity of osteoblasts.