Downregulation of Matrix Metalloproteinases 2 and 9 is Involved in the Protective Effect of Trehalose on Spinal Cord Injury

Upregulation of matrix metalloproteinases (MMPs), in particular MMP-2 and MMP-9 contributes to secondary pathogenesis of spinal cord injury (SCI) via promoting inflammation. Recently, we have reported that trehalose suppresses inflammatory responses following SCI. Therefore, we investigated the effect of trehalose on MMP-2 and MMP-9 expression in SCI. A weight-drop contusion SCI was induced in male rats. Then, the animals received trehalose at three doses of 10 (T10), 100 (T100) and 1000 (T1000) mM intrathecally. MMP-2 and MMP-9 transcripts were then measured in damaged spinal cord at 1, 3 and 7 days after trauma, and compared with vehicle and sham groups. Additionally, behavioral analysis was conducted for 1 week using Basso-Beattie-Bresnahan (BBB) locomotor rating scale. Our data showed an early upregulation of MMP-9 at 1 day post-SCI. However, MMP-2 expression was increased at 3 days after trauma. Treatment with 10 mM trehalose significantly reduced MMP-2 expression in 3 and 7 days (P< 0.01) and MMP-9 expression in 1, 3, and 7 days (P< 0.05) post-damage compared with vehicle. Nonetheless, downregulation of both MMPs was not observed in T100 and T1000 groups. In addition, T10 group showed more rapid recovery of hind limb strength compared with T100 and T1000 groups. We propose that the neuroprotective effect of low dose trehalose is mediated by attenuation of MMP-2 and MMP-9 expression.