Objective      To investigate the regeneration of peripheral nerve allografts after being preserved in University of Wisconsin solution (UW solution) containing tetramethylpyrazine (TMP) for different times at 4 ℃.       Methods      Fifty-six Wistar rats (male

weighing 200 to 250 g) were divided into 7 groups randomly

A

A′

B

B′

C

C′ and D groups (n=8) and were inflicte

d with sciatic nerve defect. The sciatic nerve allografts were collected from another 24 SD rats (3-month-old

weighing 200 to 250 g) and then preserved in UW solution containing TMP (for A

B and C groups) or not (for A′

B′ and C′ groups) at 4 ℃ for different time intervals (4

6 and 12 weeks)

and then employed to repair the sciatic nerve defect of Wistar rats. The rats from group D were treated with fresh sciatic nerve autografts and served as control. In 4

8 and 12 weeks postoperatively

the function of affected limb was observed. The weight

morphological and electric neurophysiology of gastrocnemius were measured and observed in 12 weeks postoperatively.       Results      With respect to the electrophysiological values as well as gastrocnemius weight

the results of groups A and D were better than the other groups

and those of group D were superior to those of group A (

P

＜0.05). Pathological observation in 12 weeks after transplantation indicated that the sciatic nerves of groups C and C′ were in severe infection and obvious structural disorders with vacuolar degeneration. And the infection was slightest in group D. Microscopic and transmission electron microscopic observation showed that in groups A and D

the nerve fibers were in well-arrangement

and there were more regenerative medullated nerve fibers

with integrated myelin in concentric circles and abundant organelles. The condition in group B was worse than that in group A. There were few regenerative medullated nerve fibers in groups C and C′.       Conclusion      TMP exerts its protective effect on the regeneration of allograft nerve in 4 weeks.