Antioxidative and Antiapoptotic Effects of Delta-Opioid Peptide [D-Ala2, D-Leu5] Enkephalin on Spinal Cord Ischemia-Reperfusion Injury in Rabbits.

Danyun Fu,Haitong Liu,Junyan Yao,Shitong Li,Lianhua Chen

doi:10.3389/fnins.2017.00603

Abstract

Background: In our previous study, we found that regional administration of delta-opioid peptide [D-Ala2, D-Leu5] enkephalin (DADLE) could provide dose-dependent protection on spinal cord ischemia-reperfusion (I/R) injury in rabbits. However, the relative protective molecular mechanisms underlying this neuroprotection remain unclear. The purpose of this study was to investigate whether DADLE provided the protection in spinal cord I/R injury through its antioxidant property by decreasing malondialdehyde (MDA) and nitric oxide (NO) levels and increasing glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels and through its antiapoptotic capacity by inhibiting caspase-3 and p53 expression.Methods: The rabbits were divided into three groups. The animals in Group NS and Group DADLE were administered with normal saline (NS) or DADLE via aorta during 30 min of ischemia respectively, while the one in Group Sham received no intervention. During the period of reperfusion, the rabbit's blood samples were collected for enzyme-linked immunoabsorbent assay (ELISA) examinations of MDA, NO, GSH-Px and SOD. At 48 h after reperfusion, the lumbar spinal cords were harvested for immunohistochemical, real-time polymerase chain reaction (PCR) and western blot studies to detect the caspase-3 and p53 expressions.Results: The activities of serum MDA and NO showed significant reductions in the DADLE group as compared with the control group. By contrast, the levels of serum GSH-Px and SOD were significantly higher in the DADLE group than those in the NS group. In addition, caspase-3 and p53 expression were significantly increased in the NS group, while DADLE mitigated these changes.Conclusions: The protective effects of DADLE at the dosage of 0.05 mg/kg may be related to its antioxidant and antiapoptosis properties in the rabbit model of spinal cord I/R injury.

Highlights

Spinal cord ischemia-reperfusion (I/R) is one of the most serious complication of thoracoabdominal aortic surgery, leading to postoperative paraplegia in 4 to 16% of patients (Zvara, 2002)
We studied the antiapoptotic effect of Abbreviations: [D-Ala2, D-Leu5], DADLE; I/R, ischemia-reperfusion; MDA, malondialdehyde; NO, nitric oxide; GSH-Px, glutathione peroxidase; SOD, superoxide dismutase; NS, normal saline; Polymerase Chain Reaction (PCR), polymerase chain reaction
The data revealed that serum NO from ischemic animals that treated with NS significantly increased compared with the Sham group at T5 in rabbits (P < 0.05, Figure 1B)

Summary

Introduction

Spinal cord ischemia-reperfusion (I/R) is one of the most serious complication of thoracoabdominal aortic surgery, leading to postoperative paraplegia in 4 to 16% of patients (Zvara, 2002). DADLE has been demonstrated to promote the survival of neurons in the central nervous system including decreasing methamphetamineinduced dopaminergic transporter loss through suppressing reactive oxygen species formation and inhibiting brain lipid peroxidation (Tsao et al, 1998). It remains unknown whether DADLE can protect the I/R-induced spinal cords injury through antioxidant property. The purpose of this study was to investigate whether DADLE provided the protection in spinal cord I/R injury through its antioxidant property by decreasing malondialdehyde (MDA) and nitric oxide (NO) levels and increasing glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels and through its antiapoptotic capacity by inhibiting caspase-3 and p53 expression

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