| OBJECTIVE To investigate the effects of TMP (tetramethylpyrazine, Ligustrazine) on the motor restoration and cell apoptosis of the spinal cord in rat model of moderate acute contusive SCI (spinal cord injury).METHODS A total of 96 healthy adult SD (Sprague Dawley) rats weighting between 225g and 275g were divided equally into test group and control group randomly. The acute contusive spinal cord injury models at T10 section were made according to Allen's weight-drop method. 40mg/kg of TMP was delivered to the test group, and the control group were treated with the same volume of saline vehicle 30 minutes after injury intraperitoneally. Every rat received the same dosage then on every 8 hours until sacrifice or for 5 days following SCI if the rats had survived for more than 5 days. From each group 8 rats were selected randomly and sacrificed to harvest the contused 0.3cm long spinal cord tissue and the adjacent caudal, rostral 0.3 cm long spinal cord tissue at each time point of 8, 24 hours and 3, 7, 14, 21 days following SCI. Thus 3 samples were harvested from each rat. 2 continuous histological sections of 10μm thickness were made through microtomy from the central of each sample. One section was prepared for TUNEL (terminal-deoxynucleotidyl transferase mediated nick end labeling)and the other for Hoechst staining to observe and count the apoptotic cells in 200 amplified visual field of microscopy. Software SPSS11.5 was applied to analysis the average apoptotic cells counted in microscopy of each group at every time point and if there is significant difference between the two groups at each time point. Animal behavioral scores—modified Tarlov scores and modified Avillin loxotic plate scores on spinal cord functional deficits were performed to the rats sacrificed at the 7th, 14th, 21 st day following SCI, and analysis the difference between the two groups.RESULTS Lots of apoptotic neurons and gliocytes were observed in both group rats that were sacrificed 8 and 24 hours following SCI. They distributed not only in the contused center, but also in the caudal and rostral spinal cord adjacent to the contused center. The apoptotic cells reduced 3 days following SCI, and it was further fewer 7, 14, 21 days later. The apoptotic cells in the rats of the test group that were sacrificed 8, 24 hours and 3, 7 days following SCI were significantly fewer than the corresponding rats of the control group. The modified Rivlin loxotic plate scores and modified Tarlove valution 14, 21 days following SCI indicated that the motor restoration of the test group were better than the control group.CONCLUSION TMP has protective effects on the SD rat spinal cord function after moderate contusive SCI. It can decrease the apoptotic neurons and gliocytes of the SD rats after moderate contusive SCI.
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