Objective: To investigate the effect of tetramethylpyrazine on spinal cord repair through hypothesized pathways including regulation of caspase-3, neurofilament protein NF-L, NF-H, and NF-M expression.
Methods: Allenos weight drop method was used to establish acute spinal cord injury (SCI) rat model at T10 section and was conducted in 80 adult Sprague Dawley rats that were subsequently divided into pseudo-therapy group (sodium chloride group, n=40) and tetramethylpyrazine group (treatment group, n=40). Eight normal rats were included into the pseudo-surgery normal group (n=1 for each time point). The function of spinal cord was evaluated with animal behavioral scores by measuring modified Rivilin loxotic plate degree and counting BBB score at 1, 3, 7, 14, and 21 d postoperatively. The injured spinal cord tissue samples were harvested at 1 h, 3 h, 6 h, 1 d, 3 d, 7 d, 14 d, and 21 d postoperatively (n=5 for each time point) for the preparation of continuous histological sections that were analyzed the expression of caspase-3,NF-L,NF-H, and NF-M by immunohistochemistry method.
Results: At postoperative Day 7, 14, and 21, animal behavioral scores revealed higher modified Rivlin loxotic plate degree and BBB scores in the treatment group when compared with those of the control group (P<0.05). The cells in the injured spinal cord tissue expressed significantly less caspase-3 and significantly more NF (NF-L, NF-H and NF-M) in the treatment group than those in the control group at Day 3, 7, and 14 (P<0.05). There was positive correlation between modified Rivlin loxotic plate degree and NF expression, BBB score and NF expression; and negative correlations between BBB score and caspase-3 expression, caspase-3 expression and NF expression.
Conclusion: Tetramethylpyrazine improves spinal cord healing through regulation of caspase-3 and neurofilament protein expression.