No abstract

Spinal cord injury (SCI) is a severe health problem and the mechanism involved remains elusive. The aim of the present study was to elucidate the role of C/EBP homologous protein (CHOP), a prominent protein of the endoplasmic reticulum (ER) stress-mediated apoptosis in SCI. A total of 20 adult male Sprague-Dawley rats were divided into two groups at random, ten rats were subjected to a modified Allen’s test (using a weight-drop device) to induce a SCI model and the remaining ten rats only had the corresponding vertebral lamina removed with no injury and served as the sham-operated group. Pathological changes in the spinal cord were observed 12 h after injury by hematoxylin and eosin staining and TUNEL staining was performed to visualize apoptotic cells. The expression of CHOP was also detected by immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction. The results showed that a typical apoptotic morphology, namely the increased the number of TUNEL-positive cells in the injured spinal cord. The expression levels of CHOP in the rats with SCI were increased compared with the sham-operated rats (P<0.05). These results revealed that CHOP-mediated ER stress-induced apoptosis may be involved in SCI.

Abstract. Erythropoietin (EPO) is a promising therapeutic agent used in a variety of spinal cord injuries. Therefore, identifying the specific molecular pathway mediating the neuronal protective effect of EPO after spinal cord injury (SCI) is of great value to the patients concerned. Platelet-derived growth factor (PDGF)-B is an important factor in the recovery of neurological function. We explored changes in the expression of PDGF-B in spinal cord injury rats after receiving EPO treatment. We used a weight-drop contusion SCI model, and EPO treatment group rats received single doses ofEPO (1,000 U/ kg i.p.) immediately after the operation. Seven days after the operation, the results revealed a more rapid recovery as noted by the higher BBB scores, less disruption and more neuronal regeneration of the spinal cord in the EPO treatment group than that in the SCI group. PDGF-B expression also increased in the EPO treatment group compared to that in the SCI group (P<0.01). This study showed that PDGF-B plays a role in the neuronal protective effect of EPO on spinal cord injury in rats, which may help to explain the quick recovery after EPO treatment of spinal cord injury.

Endoplasmic reticulum (ER) stress was triggered at the early stage of SCI. Increased expression of CHOP can be found in the injured segment of the spinal cord after injury. EPO treatment could prevent pathological alterations from severe spinal cord injury by reducing expression of CHOP.

Our work provides experimental evidence that the elevated expression of TSP-1 can be detected in the injured segment of the spinal cord at 12 hours after injury in diabetic rats. It may contribute to severe damage in diabetic rats after SCI.