Objective　To investigate the protection of combined application of low dose methylprednisolone (MP) and ascorbic acid in ischemia-reperfusion (I/R) injury of spinal cord model. 　Methods　Spinal cord ischemia model was induced by clamping the infrarenal aortic for 25 min. A total of 144 New Zealand white rabbits were randomized as follows: group A (negative control group)

group B (I/R group)

group C (low-dose MP treatment group

5.4 mg/kg

i.v.)

group D (Vc treatment group

200 mg/kg

i.v.)

group E (high-dose MP treatment group

30 mg/kg

i.v.)

and group F (MP+Vc treatment group

MP 5.4 mg/kg+Vc 200 mg/kg

i.v.). Then the animals of every group were reperfused for 0 and 30 min

and 6

12

24 and 48 h respectively (n=4 for each time point). Neurological function was assessed at 24 and 48-hour reperfusion was evaluated with Tarlov scoring system. The contents of MDA

SOD

CAT and GDH-Px in the spinal cord were detected at different time point. HE and TUNEL staining were used to observe the spinal cord section in 48 h after reperfusion for pathological changes and cell apoptosis. 　Results　MDA

SOD

CAT and GDH-Px levels in group A

E and F at different time were significantly decreased. but there was no significant difference among them. Tarlov scores of group E and F showed a significant increase compared with those of group C and D. HE and TUNEL staining indicated that group E and F had similar injury degree during I/R compared with group B

C and D. 　Conclusion　The co-application of low dose MP and ascorbic acid exerts similar therapeutic effect on spinal cord ischemia-reperfusion injury compared with large dose MP.