The Effect of Methylprednisolone and Riluzole on Axonal Growth after Acute Spinal Cord Injury in Rats / 대한정형외과학회잡지

ABSTRACT

PURPOSE: To determine the effect of methylprednisolone (MP) and riluzole administration on axonal growth after spinal cord injury (SCI) in rats. MATERIALS AND METHODS: Three Sprague Dawley rats (SD rat) served as controls (average 24 weeks of age) and 24 SCI SD rats scoring below 7 points on on Basso, Beattie, and Bresnahan open field test served as test subjects (total 27 SD rats; mean weight 581 g, range=427-613 g). Test subjects were divided into two groups of 12 subjects each. Group I was injected with saline (1 ml/kg) and group II was injected with MP (300 mg/kg) and riluzole (5 mg/kg) intraperitoneally. Four SD rats were sacrificed in each group at the following time points after SCI days 1, 4, and 7. We completed behavioral testing, immunohistochemical staining and RT-PCR for chondroitin sulfate proteoglycans (CSPG), and microarrays for c-JUN, ATF-2, p53, and Elk-1. RESULTS: On behavioral testing, group II showed superior results at only day 4 after SCI (p<0.05). On RT-PCR for CSPG, optical densities were 2.06 (ratio=Group I/Group II) and 2.11 at days 4 and 7, respectively. Microarray showed that lower expression of c-JUN in group II during the entire period (p< 0.05). ATF-2 showed lower expression in group II at days 4 and 7 (p<0.05). p53 showed lower expression in group I at day 1 (p<0.05). Elk-1 showed lower expression in group I at day 1 (p<0.05) and in group II at day 7 (p<0.05). CONCLUSION: Simultaneous administration of MP and riluzole led to various changes in the MAPK pathway, and decreased CSPG. Therefore, this method has a protective effect on axonal regeneration after SCI in an SD rat model.