Dural Repair Reduces Connective Tissue Scar Invasion and Cystic Cavity Formation after Acute Spinal Cord Laceration Injury in Adult Rats

Abstract

This study examined whether duraplasty after acute cervical laceration spinal cord injury (SCI) in a rat model could (1) improve cerebrospinal fluid (CSF) circulation adjacent to the injury; (2) minimize connective tissue scarring; and (3) reduce post-traumatic inflammation and cystic cavitation. Following a transverse dural/arachnoid incision and C5-6 dorsal spinal hemisection, a 5-mm2 cadaveric dura mater allograft was placed over the lesion and fixed with fibrin glue (n=12). Control animals received an identical dural/arachnoid incision and cervical dorsal hemisection without dural repair (n=12). At 1, 5, and 10 weeks post-injury, plain film myelograms were obtained to characterize CSF circulation, and stereological methods were used to compare the extent of tissue sparing between the two groups. Immunohistochemical studies were performed to assess the degree of inflammation (ED-1), connective tissue scarring (laminin and type IV collagen), and reactive astrogliosis (GFAP). Our results indicate that dural allograft can improve CSF flow adjacent to the site of injury, which may be due to reduced meningeal fibrosis/scarring at the lesion site. Stereological analysis demonstrated that duraplasty resulted in a significant reduction in lesion volume at each time-point (p<0.01) associated with a nearly complete attenuation of post-traumatic cystic cavitation (p<0.001). Immunofluorescence studies demonstrated that duraplasty reduced the infiltration of ED-1-positive macrophages/microglia into and surrounding the lesion site, which may be responsible for the marked reduction in secondary injury following duraplasty. We conclude that duraplasty following acute spinal cord laceration may (1) improve CSF flow by limiting meningeal fibrosis; (2) reduce connective tissue scar formation; and (3) attenuate macrophage accumulation and progressive secondary injury.

GM-CSF inhibits glial scar formation and shows long-term protective effect after spinal cord injury

“…Cavitation is induced by apoptosis of cells, inflammatory response and tissue degradation, which results in functional deficits after SCI [1]. Reduction of the cavity size is often involved in the functional recovery of CNS injury by various therapies such as duraplasty and graft of skin-derived precursor cells [27,28]. In this study, GM-CSF remarkably reduced the size of cavity and protected spinal cord tissues from severe damage at 3 weeks after SCI.…”

Effects of granulocyte colony–stimulating factor and granulocyte-macrophage colony–stimulating factor on glial scar formation after spinal cord injury in rats

“…6,15 In addition, a reduction in cavity size is often involved in functional recovery after CNS injury. 3,13 It is possible that the reduced glial scar formation in Groups 3 and 4 resulted in better maintenance of the integrity of the axon fibers 4 weeks after SCI.…”

Role of Early Surgical Decompression of the Intradural Space After Cervical Spinal Cord Injury in an Animal Model

“…Iannotti et al studied the histological response to a lacerationtype spinal cord injury in a rodent model 27 . They reported that, relative to animals left with a large dural defect, animals that had received a dural allograft had decreased lesional macrophage accumulation, cystic cavitation, and scarring as well as improved cerebrospinal fluid flow.…”