Transcriptional changes in soleus muscle for rats exposed to different activities after contusion injury to the spinal cord and transcriptional changes in soleus muscle with complete spinal cord transection injury

Spinal cord injury (SCI) is a devastating clinical condition resulting in significant disabilities for affected individuals. Apart from local injury within the spinal cord, SCI patients develop a myriad of complications characterized by multi-organ dysfunction. Disorders, such as lung injury, cardiovascular disease, liver damage, kidney and urinary tract dysfunction, alterations in gut microbiome, neuropathic pain, depression and altered immune responses are common in SCI patients. Such whole body, systemic responses hinder the functional recovery and can be life-threatening in SCI population. Investigations of organ specific gene expression analyses can provide a better understanding of the injury response and identify molecular targets. Consequently, this can be used to develop treatment for SCI, promoting functional recovery and overall quality of life. Overall design: Rats were subjected to a single level laminectomy at T2 vertebrae before receiving a complete transection injury or moderately-severe contusion injury (25 g-cm SCI) at the T2 spinal cord level using the NYU Impactor (W.Young, Rutgers University, Newark, NJ). After four days of recovery, all animals were housed two per cage in tiny cage (7.5” x 8.5” x 8”) as opposed to standard cage (22” x 12.5” x 8”) to restrict their motion for the duration of the study. The subjects were then randomized into one of four groups: 1) Contusion SCI + swimming (SWIM), 2) Contusion SCI + shallow water walking (SWW), 3) Contusion SCI, un-exercised, 4) Complete Transection, un-exercised and 5) un-injured and un-exercised control group. Swimming and shallow water walking as exercise intervention, began 2.5 weeks post injury in T2 contused group and was conducted 5 days a week for 10 weeks. Animals were sacrificed at 13.5 weeks post-injury for contusion SCI+Exercise, at 11.5 weeks post-injury for contusion SCI alone, and 8.5 weeks post-injury for transection SCI. Soleus muscle tissue was retrieved from each animal and total RNA was extracted for Illumina NextSeq RNA sequencing.