Sex-Related Differences in Anxiety and Functional Recovery after Spinal Cord Injury in Mice.

It has been reported that female rats have a sex-related advantage in functional recovery and neuroprotection after spinal cord injury (SCI). However, the association between anxiety and neurological function after SCI in females and males remains unclear. The purpose of this study was to examine the sex-related differences in anxiety and neurological dysfunction after SCI in mice. Adult C57/BL6 male and female mice were used. After laminectomy at the 10th thoracic level, a contusive SCI was induced. The sham group received only a T10 laminectomy. Behavior testing (anxiety, motor/sensory function) was performed for 6 weeks after SCI. The spinal cord and preserved myelinated areas at the epicenter were histologically evaluated. The correlations between anxiety and motor/sensory function or histological parameters were analyzed using the Spearman correlation coefficient. Female and male SCI groups had significant increased anxiety-like behaviors compared to pre injury. Female SCI group became significantly more anxious than males. There was no significant difference in motor/sensory functions and histological analyses between the two groups. Anxiety-like behaviors were significantly correlated with sensory function at 2 weeks after SCI in females, as well as with motor function at 2, 4, and 6 weeks after SCI in males. Anxiety-like behaviors were not significantly correlated with the spinal cord area at the epicenter in females and males. Our results revealed that females became more anxious than males after SCI. Anxiety-like behavior after SCI may be associated with functional recovery, and improving anxiety may affect functional recovery after injury.