New Model of Ventral Spinal Cord Lesion Induced by Balloon Compression in Rats

Hypoxia-treated umbilical mesenchymal stem cell alleviates spinal cord ischemia-reperfusion injury in SCI by circular RNA circOXNAD1/ miR-29a-3p/ FOXO3a axis

Spinal cord ischemia reperfusion (SCIR) injury leads to spinal cord function injury, neural dysfunction and sometimes paralysis or even paraplegia, which severely impair the physical and mental health of individuals. Mesenchymal stem cells (MSCs) are a group of stem cells that have been widely studied for treatment of various diseases. This work aimed to study the therapeutic potential of hypoxia-induced exosomal circular RNA OXNAD1 from human umbilical cord mesenchymal stem cells (HucMSCs) against SCIR. We established an in vivo rat spinal cord injury (SCI) model and conducted treatment with exosomes that isolated from hypoxia-HucMSCs. Hypoxia-HucMSCs-derived exosomal circOXNAD1 alleviated the spinal cord tissue injury in SCI, improved limb motor function, decreased production of inflammatory factors including the IL-1 β, IL-6, and TNF-α. The in vitro hypoxia and reoxygenation (H/R) model demonstrated that Hypoxia-HucMSCs-derived exosomal circOXNAD1 improved neuron proliferation and alleviated apoptosis. Mechanistically, circOXNAD1 directly interact with miR-29a-3p and miR-29a-3p targets the 3'UTR of FOXO3a in neurons. Inhibition of miR-29a-3p and overexpression of FOXO3a reversed the effects of circOXNAD1 depletion in PC12 cell phenotypes. In conclusion, Hypoxia elevated the level circOXNAD1 in exosomes that derived from HuMSCs. The exosomal circOXNAD1 alleviated SCI through sponging miR-29a-3p and consequently elevated the FOXO3a expression. Our findings provided novel evidence for MSC-derived exosomal circOXNAD1in the treatment of SCI.

Animal models of compression spinal cord injury

Compression spinal cord injuries are a common cause of morbidity in people who experience a spinal cord injury (SCI). Either as a by-product of a traumatic injury or due to nontraumatic conditions such as cervical myelitis, compression injuries are growing in prevalence clinically and many attempts of animal replication have been described within the literature. These models, however, often focus on the traumatic side of injury or mimic short-term injuries that are not representative of the majority of compression SCI. Of this, nontraumatic spinal cord injuries are severely understudied and have an increased prevalence in elderly populations, adults, and children. Therefore, there is a need to critically evaluate the current animal models of compression SCI and their suitability as a method for clinically relevant data that can help reduce morbidity and mortality of SCI. In this review, we reviewed the established and emerging methods of animal models of compression SCI. These models are the clip, balloon, solid spacer, expanding polymer, remote, weight drop, calibrated forceps, screw, and strap methods. These methods showed that there is a large reliance on the use of laminectomy to induce injury. Furthermore, the age range of many studies does not reflect the elderly and young populations that commonly suffer from compression injuries. It is therefore important to have techniques and methods that are able to minimize secondary effects of the surgeries, and are representative of the clinical cases seen so that treatments and interventions can be developed that are specific.