Abstract:

BACKGROUND: Schwann cells are considered as an important bridge material for peripheral nerve repair, and the activity of Schwann cells is a key to whether the repair of peripheral nerve injury succeeds or not.
OBJECTIVE: To investigate the effect of different frozen pretreatment temperatures on the bioactivity of embryonic rabbit’s Schwann cells preserved at ultra-low temperature.
METHODS: The embryonic rabbit’s Schwann cells were frozen at -30 ℃, -35 ℃, -40 ℃, -45 ℃, -50 ℃, -55 ℃, -60 ℃, -65 ℃ as well as -70℃ respectively, treated by a cryoprotectant, 10% dimethyl sulfoxide, at the same time, preserved in liquid nitrogen for 48 hours, and cultured for 48 hours after rapid rewarming. Morphological changes of Schwann cells were observed under transmission electron microscopy (TEM). Bioactivity of Schwann cells was assessed by MTT and ³H-TdR incorporation test assays.
RESULTS AND CONCLUSION: The ultrastructure of Schwann cells in the group of -45 ℃ remained intact under TEM; however, other experimental cells exhibited the different appearances of cryodamage such as swelling organelles, necrosis in the cytoplasm. Results in MTT and ³H-TdR assays showed that growth inhibiting rate in the group of -45 ℃ was (3.83±0.56)% and (4.41±0.71)%, which was the lowest among the experimental groups (P < 0.05). -45 ℃ is the optimal frozen pretreatment temperature that can protect the bioactivity of embryonic rabbit’s Schwann cells.