The aim of the current study was to investigate the impact of methylprednisolone (MP) on the expression of Aquaporin 4 (AQP4) and spinal edema in rats with acute spinal cord injury (ASCI). Sprague-Dawley (SD) Wistar rats were randomly divided into the following groups: control (C), sham operation (S), ASCI, and MP-treated. After the ASCI model was induced and prepared, 30 mg/kg MP was injected via the tail vein, on postoperative days 1, 3, and 7. The Tarlov scoring method was used to evaluate the neurological outcome; spinal water content was measured using the wet/dry weight method; spinal pathological changes were evaluated by hematoxylin-eosin (HE) staining, and the expression of AQP4 was detected using Western blot. Compared to the S group, the motor nerve functional score (MNFS) was significantly lower in the ASCI group. Furthermore, their spinal water content and AQP4 expression was also significantly higher (P<0.05). Moreover, compared with the ASCI group, the MNFS, spinal water content, and AQP4 expression of the MP group was significantly lower (P<0.05). The ASCI groups showed severe, perivascular and neuronal edema, a reduction in the neuron number, shrinkage of the nuclei, necrosis of some spinal tissue white matter degeneration, and the formation of numerous cysts and vacuoles. In the MP group, the spinal gray matter and white matter had much clearer borders, with reduced bleeding range and karyopyknosis. Furthermore, this group showed improved perivascular and neuronal edema and an even distribution of intranuclear chromatins. MP inhibited spinal edema in rats with ASCI, which might be related to the reduced AQP4 expression in spinal tissues.
Keywords: Acute spinal cord injury; Aquaporin 4; Methylprednisolone; Spinal edema.
© 2018 by the Association of Clinical Scientists, Inc.