Analysis of the Cell Viability and Neurite Formation Rate of the Cryopreserved Fetal Mesencephalic Neuron

ABSTRACT

Preservation of tissue viability is very important for successful fetal mesencephalic transplantation. Cryopreservation methods have been regarded as a kind of useful technique to maintain tissue viability during the preservation period. Tissue viability and neurite formation rate of cryopreserved tissue would be influenced by many factors. Authors have been looking for the most ideal condition for maintaining tissue viability of cryopreserved tissue after thawing. For the first step to define the most ideal condition of crypreservation, the present study investigated whether tissue viability and neurite formation rate could be influenced by length of cryopreservation time. We used the ventral mesencephalon from 14 day old rat embryos. Tissue blocks of ventral mesencephalon were cooled in a controlled rate freezer from room temperature to -80degreesC at a rate of 5degreesC per minute. Then tissue blocks were transfered into the liquid nitrogen tanks. We divided the tissue blocks into 4 groups(fresh, 1 week, 3 weeks, 5 weeks) by the duration of cryopreservation period. We compared the cell viability and neurite formation rate of each group after thawing. We estimated the cell viability and the neurite formation of the fresh group. The fresh group showed 92% cell viability and the other three cryopreserved groups showed 65% cell viability. Cell viability of cryopreserved group was reduced significantly after thawing, comparing with the fresh groups. But differences of neurite formation rate of each group was not significant. Our result indicates that cryopreservation time could not affect the cell viability and neurite formation rate. Therefore, if we improve the reduction rate of cell viability after thawing, we would be able to obtain the better result of fetal mesencephalic transplantation.