Decrease of PPARδ in Type-1-Like Diabetic Rat for Higher Mortality after Spinal Cord Injury

Changes in the peroxisome proliferator-activated receptors-δ (PPARδ) expression in rats after spinal cord injury (SCI) have been previously reported. Diabetic animals show a higher mortality after SCI. However, the relationship between the progress of diabetes and PPARδ in SCI remains unknown. In the present study, we used compressive SCI in streptozotocin-(STZ-) induced diabetic rats. GW0742, a PPARδ agonist, was used to evaluate its merit in STZ rats after SCI. Changes in PPARδ expression were detected by Western blot. Survival rates were also estimated. A lower expression of PPARδ in spinal cords of STZ-diabetic rats was observed. In addition, the survival times in two-week induction diabetes were longer than those in eight-week induction group, which is consistent with the expression of PPARδ in the spinal cord. Moreover, GW0742 significantly increased the survival time of STZ rats. Furthermore, their motor function and pain response were attenuated by GSK0660, a selective PPARδ antagonist, but were enhanced by GW0742. In conclusion, the data suggest that higher mortality rate in STZ-diabetic rats with SCI is associated with the decrease of PPARδ expression. Thus, change of PPARδ expression with the progress of diabetes seems responsible for the higher mortality rate after SCI.