Fetoplacental tissues including the early chorion contain stem cells with various morphological and functional characteristics .Cultured chorionic cells may be used in perspective therapies of different pathologies.

To investigate the effect of cryopreservation on proliferation and differentiation potential of chorion cell culture (ChCC).

Five freezing programs for ChCC were compared: Program 1, cooling from 25°C down to -30°C at 0.5°C/min; Program 2, cooling from 25°C down to -30°C at 1°C/min; Program 3, cooling from 25°C down to -10°C at 1°C/min with further cooling down to - 80°C at 10°C/min; Program 4, cooling from 25°C down to -5°C at 1°C/min with further cooling down to -80°C at 10°C/min; Program 5, cooling from 25°C down to -6°C at 1°C/min with further crystal seeding by adding the surplus nitrogen into the chamber, and cooling down to -80°C at 10°C/min. Viability, adhesion, proliferation and directed differentiation were examined.

Freezing program 5 achieved the best result, with the highest viability, adhesion, proliferation and directed differentiation.

The data may help establishing better cryopreservation protocols for perspective chorionic cell lines and their further application in biotechnology.