OSTEOGENESIS FROM CRYOPRESERVED PERIOSTEUM

The periosteum of Femur, which prepared from chick embryo of 18d1th day after fertilization，was cryopeserved with a cryoprotectant (0.2M treharose, 50% egg yolk，12% dimethy sulfoxide (DNSO) in huecm AH25). The following program of freezing was employed；room temperature to -7℃：-2.0s℃/min, -7.0℃to -40℃：-1.0℃/ min,transfer in liquid nitrogen. The package of cryopreserved periosteum was thawed in tap water（37℃），and cultured on allantoic sac of chick embryo of 9th day after ferilization.When compared与那些直接程序的分步选择和修复，there found no significant difference in the survival rate. the present study, therefore，employed direct procedure. The periosteum cryopreserved without DNSO gave no osteogenesis，and the optimum concentration of DMSO was found to be 6.0 to 18.0%，12% DMSO in the cryoprotectat. Addition of egg yolk improved the rate ofosteogenesis,以及similar effect was observed by使用egg yolk lecithin. Even after long term preservation (1)一周，一个month and三个months)similar survival rates were observed. Electron microscopic observation suggested that surface celllayer were denatured after thawing，当那些deep layers kept their cell structures such as plasma membrane and organelas。

The periosteum of Femur, which prepared from chick embryo of 18ィイD1thィエD1 day after fertilization, was cryopeserved with a cryoprotectant (0.2M treharose, 50% egg yolk, 12% dimethy sulfoxide (DNSO) in huecm AH25). The following program of freezing was employed ; room temperature to -7℃ : -2.0s℃/min, -7.0℃ to -40℃ : -1.0℃/min, transfer in liquid nitrogen. The package of cryopreserved periosteum was thawed in tap water (37℃), and cultured on allantoic sac of chick embryo of 9ィイD1thィエD1 day after ferilization.When compared the stepwise addition and removal of cryoprotectant with those direct procedures, there found no significant difference in the survival rate. The present study, therefore, employed direct procedure. The periosteum cryopreserved without DNSO gave no osteogenesis, and the optimum concentration of DMSO was found to be 6.0 to 18.0%, the study added 12% DMSO in the cryoprotectat. Addition of egg yolk improved the rate of osteogenesis, and similar effect was observed by using egg yolk lecithin. Even after long term preservation (1 week, 1 month and 3months), similar survival rates were observed. Electron microscopic observation suggested that surface cell layer were denatured after thawing, whereas those of deep layers were kept their cell structures such as plasma membrane and organelas.