Relationships between microRNA-20a and microRNA-125b expression and apoptosis and inflammation in experimental spinal cord injury

Objectives: The aim of the study was to determine the relationships between microRNA-20a and microRNA-125b expression and apoptosis and inflammation in a rat model of spinal cord injury (SCI) using microscopy, immunohistochemistry, and molecular biology. Methods: Sixty-one rats were divided into three groups: a control group that was not subjected to any operation; a sham-operated group; and an experimental group that was subjected to spinal cord compression. The experimental group was further subdivided into two subgroups: the experimental control group, which did not receive any drug treatment; and the methylprednisolone treatment group, which received 30 mg/kg methylprednisolone on day 0 followed by 10 mg/kg/day methylprednisolone from days 1-14. Results: Tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 levels increased in the experimental control group on days 1 and 3, and decreased in the experimental control group and methylprednisolone treatment group on days 7 and 14. Caspase-3 levels increased in the experimental control group on day 1, and decreased in the experimental control group and methylprednisolone treatment group on days 3, 7, and 14. MicroRNA-20a expression was upregulated in the experimental control group on days 1 and 3, and microRNA-125b expression was downregulated on days 3 and 7. Conclusions: After SCI, upregulated microRNA-20a expression and increased proinflammatory cytokines may lead to an increase in inflammation. MicroRNA-125b may be associated with caspase-3, and microRNA-125b downregulation may inhibit apoptosis. Although the results of this study suggest potential relationships between microRNA-20a and microRNA-125b expression and apoptosis and inflammation in SCI, further studies are needed to confirm microRNA-20a and microRNA-125b as biomarkers in SCI and to develop new strategies for the treatment of SCI.