Effects of Tetramethylpyrazine on Expression of Early Apoptosis and Caspase-3 Gene in Rats With Spinal Cord Injury

Objective:Creating acute spinal cord injury(SCI) model in rats with modified Allen's method,to observe morphology of nerve cells in early apoptosis and study caspase-3mRNA expression in rats with tetramethylpyrazine(TMP) after spinal cord injury,in order to further understand mechanism of action of Caspase-3 in apoptosis after SCI and to explain mechanism of TMP in inhibiting apoptosis at the gene level.Methods:120 adult SD rats were randomly divided into 4 groups:normal group,model control group,MP treatment group and the TMP treated group,30 rats in each group.By modified Allen's method of making weight spinal cord injury model was established,after the SCI model was made,MP and TMP group were injected the same volume of saline on time.Neurological scores(BBB method) were recorded at different time points after injury.Apoptosis and morphological changes were observed by flow cytometry case and by transmission electron microscopy.While Caspase-3mRNA expression were detected by RT-PCR at different time points after injury.Results:Apoptosis rates of nerve cells of model group appeared in early apoptosis in 6h,Apoptosis rates compared 48h with 24h,decreased slightly,but still sustained at a high level,the difference was not statistically significant(P0.05).The difference of apoptosis rates between TMP and MP treatment group at each time point was not statistically significant(P0.05),but compared with model group,the difference was statistically significant(P0.05).Caspase-3mRNA expression was similar at different time points after injury,both have a volume-time dependent relationship.The difference of apoptosis rates and Caspase-3mRNA both TMP group and MP group at different time points after injury was not statistically significant(P0.05),but the difference compared the TMP group and the MP group with the model group were significant(P0.05).Conclusion:The study found that the early apoptosis of nerve cells in rats 6h after SCI shows the start of apoptosis to be significantly ahead of time than morphological changes seen under the electron microscope;Caspase-3mRNA levels in the damage area were significantly increased,and the ratio of apoptosis and changes of ultrastructure shows obvious relevance;the early use of TMP can reduce the nerve cell apoptosis and have some neuroprotective effect on rats with SCI.The main mechanism of inhibition of apoptosis may be related with Cascading effect.