2023, Vol. 27 ›› Issue (1): 114-120

Cellular microenvironment in nerve repair after spinal cord injury

Zhu Zhenghuan, Zou Hongjun, Song Zhiwen, Liu Jinbo   

Abstract: BACKGROUND: Previous studies have shown that a single change in the expression of a gene or the state of a cell in the area of spinal cord injury has no significant effect on functional recovery after spinal cord injury. An increasing number of evidence shows that the regulation of cellular microenvironment after spinal cord injury is a key factor hindering the recovery of neurological function.
OBJECTIVE: To review the biological characteristics of cellular microenvironment before and after spinal cord injury, including the effect and mechanism of mutual regulation among different kinds of cells and extracellular components on nerve repair after spinal cord injury.
METHODS: The first author retrieved the databases including PubMed and Web of Science for articles published from January 2000 to December 2021 using the key words of “spinal cord injury, glial cell, neuron, immune cell, neural stem cell, extracellular matrix, cytokine, extracellular vesicle, regeneration”. Finally, 64 articles were selected for analysis.
RESULTS AND CONCLUSION: (1) After spinal cord injury, among the cellular components of the cellular microenvironment, the interaction among glial cells, which account for the highest proportion, and the interaction with neurons are particularly critical. (2) Among the extracellular components after spinal cord injury, the hydrogels with good biocompatibility used to imitate natural extracellular matrix can effectively simulate and reconstruct the cellular microenvironment in the injured area and promote axonal elongation. (3) Among the extracellular regulatory factors after spinal cord injury, pro-inflammatory factors such as tumor necrosis factor-α and interleukin-1β aggravate the inflammatory storm of cellular microenvironment. Using receptor inhibitors or blocking related pathways to down-regulate the expression of adverse extracellular regulatory factors is an effective therapeutic method in the cellular microenvironment. At the same time, there are also studies on increasing the expression of anti-inflammatory factors such as interleukin-10 in the microenvironment of the spinal cord and on inhibiting the development of inflammation in the injured area. (4) Recently, extracellular vesicles have also played an important role in the cellular microenvironment as carriers of information. (5) This article reveals multiple sets of mutual regulatory relationships between cellular components and extracellular components in the cellular microenvironment after spinal cord injury, emphasizing that the neuroreparative effects of various components in the cellular microenvironment are not isolated.
Key words: spinal cord injury, cellular microenvironment, glial cell, neuron, immune cell, extracellular matrix, extracellular vesicle, nerve repair