The Effect Of Tetramethylpyrazine On The Expression Of Caspase-3,NF(NF-L,NF-H,NF-M) After Acute Spinal Cord Injury In A Rat Model

OBJECTIVE This study was to investigate the expression of Caspase-3,NF-L,NF-H,NF-M in spinal tissues of rats with acute spinal cord injury after Teramethylpyrazine (TMP) treatment.METHODS A total of 55 healthy adult Sprague Dawley rats weighting 200g up to 250g were divided randomly into three groups without discriminating of gender : (1)Pseudo-Surgery normal group (group S, n=8); (2) Pseudo-Therapy normal group (group C, n=40); (3) Tramethylpyrazine group (group T, n=40).The acute spinal cord injury models at T10 section were made according to Allen's weight drop method .200mg/kg of TMP was used to the T group intraperitoneally and the C group were treated with the same volume of saline vehicle (NS) 30 minutes after injury. Each model was given the same dosage once a day until executed(lasted less than 5days) or lasted for 5 days following the injury if the rats was executed after 5th day. At the corresponding time points following the injury, the rats of two groups which related to the time point were killed and collect the spinal cord tissue samples from the injured segment with the length of 1cm. Each sample got 2 continuous histological sections of 10um thickness through microtomy in the middle of the sample. Three section was prepared to test Caspase-3, NF-L,NF-H,NF-M by immunohisto- chemistry method separately .The number of NTFs in every section was counted ,and the average positive NTFs cells of each group at the same time point were calculated. Software SPSS10.0 was applied to analysis if there was significant difference between the two related groups at each time point. Animal behavioral scores—modified by Rivilin loxotic plate and BBB score on spinal cord functional deficits were performed to the rats(executed at the first day and later) following SCI to analysis the difference between the two groups.RESULTS The number of Caspase-3 positive cells were significantly lower in T group than C group and S group at 3,7,14d after SCI(p<0.05).At the same time,the number of NF-L,NF-H and NF-M positive cells were significantly higher in T group (p<0.05).The number of Caspase-3 reached bottom at 7d,while The number of MF-L reached the ace.At the third day postop the number of NF-H and NF-M reached ace. Statistical result read as:the express of Caspase-3 3 days post-op is negative with NF-H,while negative with NF-M 7 days post-op; the express of NF-L 3 days post-op is positive with NF-M,NF-M and NF-H 3 days and 21 days post-op,while positive with NF-H 6h and 7d post-op (p<0.05).Rats treated with TMP had better outcomes in modified Rivlin loxotic plate test compared with rats of pseudo-therapy groups. And at the time point of 7d, 14,21d after SCI respectively (p<0.05). Statistical result read as: outcomes in modified Rivlin loxotic plate test is positive with NF-L of Caspase-3 7 days post-op,while positive with NF-H 14 days post-op(p<0.05).T group had significantly higher scores in BBB test than P group at 7,14,21 days after SCI respectively(p<0.05) Statistical result read as: scores in BBB test is positive with NF-L of Caspase-3 14 days post-op,while positive with NF-M 21 days post-op(p<0.05).CONCULUSION The TMP can increase the expressions of the Caspase-3 ,NF-L,NF-H,NF-M of the SD rats after SCI. It has neuroprote-ctive effects on the second injury mechanism of the SCI.