The Roles of Superoxide on At-Level Spinal Cord Injury Pain in Rats

Promising Advances in Pharmacotherapy for Patients with Spinal Cord Injury-A Review of Studies Performed In Vivo with Modern Drugs

Spinal cord injury (SCI) is a pathological neurological condition that leads to significant motor dysfunction. It is a condition that occurs as a result of tragic accidents, violent acts, or as a consequence of chronic diseases or degenerative changes. The current treatments for patients with SCI have moderate efficacy. They improve the quality of life of patients, but they are still doomed to long-term disability. In response to the modern directions of research on possible therapeutic methods that allow for the recovery of patients with SCI, a scientific review publication is needed to summarize the recent developments in this topic. The following review is focused on the available pharmacological treatments for SCIs and the problems that patients face depending on the location of the injury. In the following review, the research team describes problems related to spasticity and neuropathic pain; possible therapeutic pathways are also described for neuroprotection and the improvement of neurotransmission within the injured spinal cord, and the review focuses on issues related to oxidative stress.

Targeted up-regulation of Drp1 in dorsal horn attenuates neuropathic pain hypersensitivity by increasing mitochondrial fission

Mitochondria play an essential role in pathophysiology of both inflammatory and neuropathic pain (NP), but the mechanisms are not yet clear. Dynamin-related protein 1 (Drp1) is broadly expressed in the central nervous system and plays a role in the induction of mitochondrial fission process. Spared nerve injury (SNI), due to the dysfunction of the neurons within the spinal dorsal horn (SDH), is the most common NP model. We explored the neuroprotective role of Drp1 within SDH in SNI. SNI mice showed pain behavior and anxiety-like behavior, which was associated with elevation of Drp1, as well as increased density of mitochondria in SDH. Ultrastructural analysis showed SNI induced damaged mitochondria into smaller perimeter and area, tending to be circular. Characteristics of vacuole in the mitochondria further showed SNI induced the increased number of vacuole, widened vac-perimeter and vac-area. Stable overexpression of Drp1 via AAV under the control of the Drp1 promoter by intraspinal injection (Drp1 OE) attenuated abnormal gait and alleviated pain hypersensitivity of SNI mice. Mitochondrial ultrastructure analysis showed that the increased density of mitochondria induced by SNI was recovered by Drp1 OE which, however, did not change mitochondrial morphology and vacuole parameters within SDH. Contrary to Drp1 OE, down-regulation of Drp1 in the SDH by AAV-Drp1 shRNA (Drp1 RNAi) did not alter painful behavior induced by SNI. Ultrastructural analysis showed the treatment by combination of SNI and Drp1 RNAi (SNI + Drp1 RNAi) amplified the damages of mitochondria with the decreased distribution density, increased perimeter and area, as well as larger circularity tending to be more circular. Vacuole data showed SNI + Drp1 RNAi increased vacuole density, perimeter and area within the SDH mitochondria. Our results illustrate that mitochondria within the SDH are sensitive to NP, and targeted mitochondrial Drp1 overexpression attenuates pain hypersensitivity. Drp1 offers a novel therapeutic target for pain treatment.