The Effect Of Tetramethylpyrazine On The Expression Of MIF,NF-ΚB And Ⅰ-ΚBα After Acute Spinal Cord Injury In The Rat Model

OBJECTIVE:To study the effect of Teramethylpyrazine(TMP) on the expressions of MIF(macrophage migration inhibitory factor),NF-KB (nuclear factorκappa B) and I-KBα(inhibitorκappa B) genes in the acute spinal cord injury(ASCI) in rats and approach to investigate the protective effect and possible mechanism of TMP on ASCI.METHODS:110 adult Sprague Dawley rats with 250-300g body weight(BWT) were randomly divided into three primary groups:(1) Sham operation group(group S,n=10);(2) Control group(group C, n=50);(3) Teramethylpyrazine treated group(group T,n=50).The C and T group animals were further divided into 10 sub-groups(n=5 per sub-group) each at 1,3,6,and 12 hrs and 1,3,5,7,14 and 21 days of survival before euthanasia.Allen's weight drop method was used to establish the acute spinal cord injury(ASCI) rat model at T₁₀ section in the C and T groups.A dose of 200mg/kg BWT of TMP was administered in the T group animals intraperitoneally,the C group animals were treated with the same volume of normal saline solution(NS) 30 minutes after injury.Each animal was treated once a day until euthanasia or survived for 5 days following the spinal cord injury if the rats survived for more than 5 days.The animal behavioral scores for evaluation of the spinal cord functional deficits including modified Rivilin loxotic plate test,CBS(Combine Behavior Score) and BBB(Basso,Beattie, Bresnahan) locomotor rating scale were performed on the rats euthanized at 1,3,5,7,14,and 21 days following ASCI.The differences between the group C and group T specimens were analyzed by statistical analysis. The injured spinal cord tissue was harvested at the each time point postoperatively for preparing the cross sections of 10μm thickness that were used to evaluate the MIF,NF-KB and I-KBαgene expression using immunohistochemistry methods.The stained cells with MIF,NF-KB and I-KBαpositive expression of each sample were counted.The averaged positive MIF,NF-KB and I-KBαexpression cells of each group at the same time point were compared by statistical analysis.The software SPSS13.0 was applied to determine if there was significant difference between group C and T at each time point.RESULTS:The results of the modified Rivlin loxotic plate test showed that the significantly higher degrees were found in T group than those in C group at 7,14 and 21days postoperatively(p<0.05).The significantly higher BBB score and lower CBS score were found in T group than those in C group at 5,7,14 and 21 days after ASCI respectively(p<0.05).There were more MIF positive expression cells in the C group when compared with those in T group at 12 hrs,1,3,5 and 7 days after ASCI(p<0.05).The number of NF-KB positive cells was significantly lower in group T than that in group C at 1,3,5 and 7 days after ASCI(p<0.05).The number of I-KBαpositive cells was significantly higher in group T than that in group C at 1,3,5 and 7 days after ASCI(p<0.05).CONCLUSION:1.TMP has positive protective effect in the acute spinal cord injury(ASCI),and tends to promote the repair of injured spinal cord tissue;2.The TMP may increase the I-KBαexpression and decrease the MIF and NF-KB expressions in cells after ASCI.