Comparision of Slow Freezing and Vitrification for the Efficient Cryopreservation of Transgenic Rice Cells

초록

Transgenic rice cell lines (Oryza sativa L.) producing recombinant human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig) were preserved in liquid nitrogen. Cryopreservation procedure should ensure high survival and regeneration of cryopreserved cells after thawing. Therefore, establishment of the cell banking system is essential. In slow freezing method, dehydration of cells was caused in slow or quick cooling steps in liquid nitrogen. Pre-culture medium was developed with 0.5 M sucrose and cryoprotectants containing 1 M sucrose, 0.5 M glycerol and 0.5 M DMSO. During the slow freezing step, ice crystals were formed and exerted detrimental effects on the cells. In vitrification, high cooling rate was applied with high concentrations of cryoprotectants to avoid lethal injury. A vitrification solution was consisted of 30% glycerol, 15% ethylene glycol, 15% DMSO and 0.4 M sucrose. In this study, two cryopreservation techniques were utilized and compared for transgenic rice cells.