Objective:To investigate the effects of vitreous cryopreservation with tetramethylpyrazine on schwann’s cell apoptosis and the expression of regulating gens under differenttemperatures. Methods:48 sciatic nerves obtained from 24 SD rats were randomly divided into 2 groups (each with 24 nerves): experimental group(with tetramethy -lpyrazine

320mg/L)and control group(no tetramethylpyrazine). Experimental group included 4 subgroups :A B C D;and the control group included 4 subgroups: A’

B’

C’

D’(each with 6 nerves). All the corresponding subgroups werecryopreserved3weeksunderdifferenttemperature(sAA’:-4℃

BB’:-20℃

CC’:-80℃

DD’:-196℃).After 3 weeks

all the nerves were obtained for tests: ①HE staining for light-microscope test

② Schwann’S cell apoptosis was measured quantitatively by the terminal transferase UTP nick end labeling (TUNEL)method

③The expression of Bcl-2 and Bax was determined by immunohistochemisty technique. Results:Aside from D D’subgroups

the number of Schwann’s cell apoptosis in each experimental subgroup was significantly smaller than that in the corresponding control subgroup(P<0.05);the expression of Bcl-2 were significantly increased in each experimental subgroup compared with that in the correspondingcontrol subgroup and the expression ofBaxdecreased significantly(P<0.05). In the experimental group

the rate of Schwann’S cell apoptosis and that of the positive expression of Bcl-2(or Bax)in B subgroup were approximately equal to those in C and D subgroup(P>0.05). Conclusion:These findings suggest that at -20℃ vitreous cryopreservation with TMP can depress Schwann’S cell apoptosis of rat by regulating the expression of Bcl-2 and Bax.