The Effect Of Tetramethylpyrazine On The Expression Of FADD And The Activity Of Caspase-8 After Acute Spinal Cord Injury In The Rat Model

OBJECTIVE: To study the effect of Teramethylpyrazine (TMP) on the expression of FADD and the activity of Caspase-8 in acute spinal cord injury(ASCI) in rats and approach the protective effect and possible mechanism of TMP in ASCI.METHODS : 99 SD rats weighting 250g up to 300g were divided randomly into three groups:(l) Sham operation group (group S, n=9); (2) Control group (group C, n=45); (3) Tramethylpyrazine group (group T, n=45). 200mg/kg of TMP was used to the T group intraperitoneally , the S and C groups 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 sacrifice or lasted for 5 days following the injury if the rats survived for more than 5 days. The rats of three groups were killed to collect the spinal cord tissue samples at the each time point following the injury. Each sample got histological sections of 10um thickness through microtomy in the middle of the sample. The section was prepared to test the FADD by immunohistochemistry method separately .The number of FADD positive cells in every section was counted ,and the average FADD positive cells of each group at the same time point were calculated. Each sample got 10mg tissue in the middle of the sample.The tissue was homogenized to test the consistency of activity unit of Caspase-8. The consistency of activity unit of Caspase-8 in every tissue was counted ,and the average consistency of activity unit of Caspase-8 of each group at the same time point were calculated. Animal behavioral scores—modified Rivilin loxotic plate test,BBB and CBS score on spinal cord functional deficits were performed to the rats sacrificed at the 1 day,3 day, 7 day 14day and 21 day following SCI, and analysis the difference between the group C and group T. Software SPSS 13.0 was applied to analysis if there was significant difference among the three related groups at each time point.RESULTS: T group had significantly higher degrees than C group at 7d,14d and 21d in modified Rivlin loxotic plate test after SCI (p<0.05).T group had significantly higher scores in BBB score than C group at 7,14 and 21 days after SCI respectively(p<0.05). C group had significantly higher scores in CBS score than T group at 7,14 and 21 days after SCI respectively(p<0.05).The number of MIF positive cells were significantly higher in C group than T group at 12h, 1d,3d,5d and 7d after SCI(p<0.05); The number of FADD positive cells were significantly lower in T group than in C group at 3d,7d and 14d after SCI(p<0.05); The consistency of activity unit of Caspase-8 were remarkable lower in T group than in C group at 3d,7d and 14d after SCI(p<0.01).CONCLUSION:①The TMP can promot the restoration of sequential spinal cord injury (SSCI).②The TMP can inhibit the expression of the FADD and the activity of Caspase-8 after ASCI.