Therapeutic effect of methylprednisolone combined with high frequency electrotherapy on acute spinal cord injury in rats

Acute spinal cord injury (SCI) has a high rate of disability and mortality. Although secondary SCI results in local tissue hypoxia and the release of inflammatory mediators, it is both controllable and reversible. Therefore, timely rehabilitation treatment is beneficial for the partial recovery of patients with SCI. The present study aimed to investigate the use of methylprednisolone combined with high-frequency electrotherapy as a method of rehabilitation treatment in rats with SCI. The rat SCI model was prepared using the modified Allen's method with the animals randomly divided into the following 4 groups (n=10 for each group): SCI; methylprednisolone (300 mg/kg); high-frequency electrotherapy; and combination treatment with electrotherapy combined with methylprednisolone (300 mg/kg). The Basso, Beattie and Bresnahan (BBB) score, somatosensory evoked potential (SEP) and motor evoked potential (MEP) were used to assess spinal function. Brain-derived neurotrophic factor (BDNF) and NF-κB expression levels were detected using reverse transcription-quantitative PCR and western blotting. Tumor necrosis factor (TNF)-α and IL-2 expression levels were determined by ELISA, and caspase 3 activity was also assessed. In all treatment groups, BDNF mRNA and protein expression levels were significantly increased, whilst those of NF-κB were reduced. Additionally, an elevated BBB score, improved SEPs and MEPs, inhibited caspase 3 activity and downregulated TNF-α and IL-2 expression levels were observed, compared with the SCI group (P<0.05). However, the combination group exhibited more significant effects on SCI. In conclusion, methylprednisolone combined with high frequency electrotherapy may improve the symptoms of SCI by increasing the expression level of BDNF, reducing that of NF-κB, and suppressing the secretion of inflammatory factors.