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Chronic expression of PPAR‐δ by oligodendrocyte lineage cells in the injured rat spinal cord
Author(s) -
Almad Akshata,
McTigue Dana M.
Publication year - 2010
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.22242
Subject(s) - oligodendrocyte , biology , spinal cord , peroxisome proliferator activated receptor , lesion , myelin , spinal cord injury , transcription factor , microbiology and biotechnology , endocrinology , medicine , anatomy , neuroscience , pathology , receptor , central nervous system , genetics , gene
The transcription factor peroxisome proliferator‐activated receptor (PPAR)‐δ promotes oligodendrocyte differentiation and myelin formation in vitro and is prevalent throughout the brain and spinal cord. Its expression after injury, however, has not been examined. Thus, we used a spinal contusion model to examine the spatiotemporal expression of PPAR‐δ in naïve and injured spinal cords from adult rats. As previously reported, PPAR‐δ was expressed by neurons and oligodendrocytes in uninjured spinal cords; PPAR‐δ was also detected in NG2 cells (potential oligodendrocyte progenitors) within the white matter and gray matter. After spinal cord injury (SCI), PPAR‐δ mRNA and protein were present early and increased over time. Overall PPAR‐δ+ cell numbers declined at 1 day post injury (dpi), likely reflecting neuron loss, and then rose through 14 dpi. A large proportion of NG2 cells expressed PPAR‐δ after SCI, especially along lesion borders. PPAR‐δ+ NG2 cell numbers were significantly higher than naive by 7 dpi and remained elevated through at least 28 dpi. PPAR‐δ+ oligodendrocyte numbers declined at 1 dpi and then increased over time such that >20% of oligodendrocytes expressed PPAR‐δ after SCI compared with ∼10% in uninjured tissue. The most prominent increase in PPAR‐δ+ oligodendrocytes was along lesion borders where at least a portion of newly generated oligodendrocytes (bromodeoxyuridine+) were PPAR‐δ+. Consistent with its role in cellular differentiation, the early rise in PPAR‐δ+ NG2 cells followed by an increase in new PPAR‐δ+ oligodendrocytes suggests that this transcription factor may be involved in the robust oligodendrogenesis detected previously along SCI lesion borders. J. Comp. Neurol. 518:785–799, 2010. © 2009 Wiley‐Liss, Inc.