Inhibitory proteoglycan immunoreactivity is higher at the caudal than the rostral Schwann cell graft-transected spinal cord interface.
To begin to evaluate the influence that proteoglycans may have on the success of Schwann cell (SC) transplants to induce axonal regrowth across a complete transection lesion and beyond, we determined the pattern of expression of inhibitory chondroitin sulfate proteoglycans (CSPGs) 3 weeks after transplantation into completely transected adult rat thoracic spinal cord. Using immunohistochemistry, we observed that: (1) CSPGs recognized by CS-56 antibody are present on astrocytes, fibroblasts, and SCs in the distal graft, and at lesion and cystic cavity borders; (2) CS-56 immunoreactivity (IR) is greater at the caudal SC graft-host cord interface than the rostral interface; (3) phosphacan-IR, also greater at the caudal interface, is associated with astrocytes, fibroblasts, as yet unidentified cells, and extracellular matrix; (4) neurocan-IR is present on astrocytes and as yet unidentified cells in grey and white matter; and (5) NG2-IR is associated with matrix near SC grafts, unidentified cells mainly in white matter, and lesion borders and cysts. Neither oligodendrocytes nor activated macrophages/microglia were immunostained. In sum, the CSPGs studied are increased at 3 weeks, especially at the caudal SC graft-cord interface, possibly contributing to an inhibitory molecular barrier that precludes regrowing descending axons from entering the caudal host cord.
The Chambers Family Electron Microscopy Laboratory, The Miami Project to Cure Paralysis, FL, USA. gplant@anhb.uwa.edu.au
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D000818:Animals; D000906:Antibodies; D001672:Biocompatible Materials; D011508:Chondroitin Sulfate Proteoglycans / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D003094:Collagen; D004338:Drug Combinations; D005260:Female; D007797:Laminin; D008854:Microscopy, Electron; D009416:Nerve Regeneration / Q000502:physiology; D011509:Proteoglycans; D051381:Rats; D011916:Rats, Inbred F344; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5; D012583:Schwann Cells / Q000737:chemistry* / Q000637:transplantation* / Q000648:ultrastructure; D013119:Spinal Cord Injuries / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*
D000906:Antibodies; D001672:Biocompatible Materials; D011508:Chondroitin Sulfate Proteoglycans; D004338:Drug Combinations; D007797:Laminin; D011509:Proteoglycans; C059485:matrigel; D003094:Collagen; C516897:Ptprz1 protein, rat; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5