Exercise role on inflammatory and MCH-1 plasticity markers in severely contused spinal cord injured rodents

Abstract

Approximately 17,500 new cases of Spinal cord Injury (SCI) occur annually in the United States. Growing evidence suggests that mobilizing the body following SCI through physical therapy regimens can help patients regain locomotor function. The immune response and the role of inflammation following SCI represents an important factor contributing to plasticity and recovery of function post-injury. The immune response uses both pro and anti-inflammatory factors to facilitate healing at the primary and secondary injury. In the severe case of SCI, inflammation can lead to maladaptive plasticity and that can hinder locomotor recovery. Pro-inflammatory cytokines such as Tumor necrosis factor alpha (TNF-a) can enhance the C-fiber activation in the dorsal horn resulting in sensitization and maladaptive plasticity. Exercise can also be pro-inflammatory. Exercise has been shown to decrease TNF-a levels and increases Interleukin-10 (IL-10) in human skeletal muscle. Bodyweight treadmill training in SCI animal has shown improvements in locomotor function. Interleukin-10 (IL-10), demonstrates potent anti-inflammatory effects in which it down-regulates TNF-alpha and its secondary effects. In addition, major histocompatibility complex class I proteins (MHC1), play a vital role in maintaining the structural integrity of neurons which is critical for fostering an environment for spinal plasticity to occur. In this study, we focus on the role of training paradigms to be used to facilitate locomotor recovery in spinally contused rats. The Body-Weight Supported Treadmill Training (BWSTT) and circular Bodyweight-Supported Ambulatory Rodent Trainer (cBART) both represent locomotor training for SCI animals. Mid-thoracic spinal cord contusion was performed, and the animals were allowed to recover for two weeks. The contused BWSTT alone, or cBART alone or combined BWSTT and cBART training groups were initiated at beginning of the third week for a total of 8-weeks of training. Controls include contused rats that received no training, and intact group (SHAM). At 10 weeks, the spinal cord was dissected for qPCR study. We measure the levels of TNF-alpha, MHC1, and IL-10 in the thoracic segment above the injury site, the injury site, Lumbar 1-3 and Lumbar 3-5 segment. Results show that in the cBART trained group, the MHC-1 expression in the L3-L5 segment was significantly greater when compared to the contused injury with no training intervention. No training effect was realized in MHC-1 in the L1-L3 trained groups. The training paradigms did not modulate TNF-a levels in the lumbar spinal cord segments. Lastly, IL-10 expression was undetectable in all the spinal cord segments. In this severe spinal cord contused model, we were only able to show modulation in the MHC-1 expression in the trained lumbar segment as function of exercise. Additional work will be required to consider the intensity of locomotor training and the severity of spinal cord contusion impact on these plasticity markers. Future understanding of these mechanisms may be useful in developing better locomotor training methods and drug targets for facilitation of recovery following SCI. CSULA RSCA 2020 MINI Grant- Dr. Joseph CSULA MORE Programs Offce, MBRS-URISE (1734GM145503) Bridges to Doctorate 5T23GM146700 NIH R25HD097701-04 - Dr. Ray De Leon. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.