Induction of IGF-1 mRNA expression following traumatic injury to the postnatal brain.
A variety of adult, non-neural tissues respond to injury by increasing expression of the gene which encodes for insulin-like growth factor-1 (IGF-1). This response is thought to be a key component in the regenerative capacity of these tissues. In contrast, the central nervous system (CNS) has relatively little regenerative capacity following injury. Interestingly, compared to many non-neuronal tissues, little IGF-1 mRNA can be detected in the adult CNS, raising the possibility that its lack of regenerative capacity is related its relative lack of IGF-1 expression. However, in the 2-week-old adolescent CNS IGF-1 mRNA can be detected in numerous brain regions. Therefore, the purpose of this study was to determine the responsiveness of the IGF-1 gene to injury in adolescent CNS tissue, a period in which expression of this gene is relatively abundant. Expression of IGF-1 mRNA was measured by means of a sensitive solution hybridization/RNase protection assay in the parieto-occipital lobes of 2-week-old and adult mice following penetrating injury. Levels of IGF-1 transcript in the injured brains were significantly increased above those of controls in both 2-week-old and adult brains 3-day post injury and remained elevated for 1 week after injury. These observations demonstrate that the adult CNS, like other tissues, can respond to injury by increasing expression of IGF-1 mRNA.
Li
X S
XS
Department of Neuroscience and Anatomy, Hershey Medical Center, The Pennsylvania State University, Hershey, PA 17033, USA.
Williams
M
M
Bartlett
W P
WP
D000367:Age Factors; D000818:Animals; D001253:Astrocytes / Q000737:chemistry / Q000502:physiology; D015870:Gene Expression / Q000502:physiology; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics; D005911:Gliosis / Q000503:physiopathology; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D009778:Occipital Lobe / Q000293:injuries* / Q000503:physiopathology; D010296:Parietal Lobe / Q000293:injuries* / Q000503:physiopathology; D012333:RNA, Messenger / Q000378:metabolism; D014951:Wounds, Stab / Q000503:physiopathology*
D005904:Glial Fibrillary Acidic Protein; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I