Neuroprotective Effects Of Tetramethypyrazine On Spinal Cord Injury In Dogs

Purpose: To explore the neuroprotective effects of tetramethypyrazine (TMP) on acute spinal cord injury in dogs .Methods: By the striking of the spinal cord at the level of T13 with Allen's device ,Acute spinal cord injury was induced in anesthetized dogs .All Animals receive high selectivity arterial duct intubation. Animals were randomly divided into three groups. Group A (n=6)was the control group and received operation but only saline treatment; group B(n=6)is the lower dosage tetramethypyrazine treatment group, a dose of tetramethypyrazine(15mg/kg)was administered with the hyperselective arterial duct by the frequency of once per day PO; group C(n=6)is the higher dosage tetramethypyrazine treatment group, a dose of tetramethypyrazine(30mg/kg)was administered with the hyperselective arterial duct by the frequency of once per day PO. MRI was performed at 30min,24h,72h,1w after injury. Neurological status was assessed by using the Xu shao-ting scoring system at 30min,24h,48h,72h,1w after injury, Dogs were killed at 1w PO. and spinal cords were harvested for histopathology observation . Immunohistochemical technique and image analysis was used to examine the expression of NF in neurons,GFAP in astrocytes Results: The scores of C group are higher than the scores of A group and B group ,So the higher dosage tetramethypyrazine-treated dogs had significantly better neurology outcome compared with control group and lower dosage tetramethypyrazine-treated group . Histopathologic analysis disclosed severe injury in the spinal cord tissue of all control dogs compared with the higher dosage tetramethypyrazine-treatment group. We find many pathological changes on the injury spinal cord such as: edema ,necrosis of the neuron , little focal bleeding and the formation of sac full of fluid. By the observation on the immunohistochemical slices and image analysis by the Image-pro plus image analysis system. we find out that most tetramethypyrazine-treated dogs had less injury compared with the saline-treatment control group and the B group. Tetramethypyrazine significantly increased the expression of the NF in neuron and GFAP in the astrocytes . Conclusion: tetramethypyrazine treatment have neuroprotection effect and the action of neuroprotection effect is depend on the dosage of the drug.