Characterization of lumbar lymph node, a CNS-specific draining lymph node, after spinal cord injury in rats

Abstract

Regional tissue-draining lymph nodes are the major active site after inflammation that generate primary immune responses according to lymphatic system pathways. However, CNS specific draining lymph nodes have not characterized individually after spinal cord injury (SCI). Therefore, we examined the morphofunctional state of the Lumbar lymph node, the closest CNS-draining lymph node adjacent to the lesion site in thoracic spinal cord injury. Findings: Lumbar lymph nodes isolated 7 days after low thoracic spinal cord injury were compared with sham control and intact control rats. The significant enlargement was observed in lumbar lymph nodes in SCI group accompanied by increased total cell number, while there was a significantly higher cell death rate. Besides, the proliferation test performed on lymphocytes lumbar lymph nodes one week after SCI revealed accelerated proliferation rate compared to sham and intact control groups, which was associated with significant elevation of IFN-γ/IL4 ratio, which confirms adaptive immunity is biased towards the Th1 pro-inflammatory responses. Conclusions: Accordingly, we conclude that the lumbar lymph node is an important CNS-draining lymph node for understanding the immunopathology of SCI, which needs to be considered as a major active lymphoid organ adjacent to the lesion site.