Related Experiment Video
Updated: Jul 25, 2026
Stereotactic Atlas-Guided Laser Capture Microdissection of Brain Regions Affected by Traumatic Injury
Published on: September 11, 2017
Expression of mRNA for glial fibrillary acidic protein after experimental cerebral injury
P A Cancilla1, J Bready, J Berliner
1Department of Pathology, UCLA School of Medicine 90024.
Abstract:
This study was undertaken to determine whether a mRNA for glial fibrillary acidic protein (GFAP) was present in increased amounts as a response to injury and, if so, how was its temporal expression related to the demonstration of GFAP by immunocytochemical techniques. A cerebral freeze-injury was produced in mice and at intervals thereafter the animals were anesthetized, perfused with formalin and histological sections of the brain through the injured area were prepared. A riboprobe for GFAP mRNA labeled with S35 and an immunocytochemical probe for GFAP were utilized to localize mRNA and GFAP immunoreactivity, respectively. For mRNA studies, the histological slide exposed to either sense or antisense probe was overlaid with x-ray film or dipped in photographic emulsion. The developed film was quantitated by digital image analysis. Emulsions were examined by dark-field microscopy. The results indicate that mRNA for GFAP is increased in the cortex in the environs of the injury by 6 hours, becomes maximal at 4-5 days, and is present in increased amounts up to 14 days. The message is enhanced in the adjacent cortex, the subpial region, the adjacent corpus callosum and in the ipsilateral and contralateral callosal radiations. This pattern of enhancement follows the distribution of post-injury edema. Glial fibrillary acidic protein is demonstrable at 24-48 hours after injury. Thus, there is a rapid response of the astrocyte to injury with increased mRNA expression that is followed by expression of GFAP immunoreactivity.
Insights
Messenger RNA (mRNA) for glial fibrillary acidic protein (GFAP) increases rapidly after brain injury in mice, preceding the detection of GFAP protein. This early mRNA response highlights astrocyte reactivity to damage.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Astrocytes play crucial roles in brain injury response.
- Glial fibrillary acidic protein (GFAP) is a key intermediate filament protein in astrocytes.
- Understanding the temporal expression of GFAP and its mRNA is vital for studying astrocyte activation.
Purpose of the Study:
- To investigate the presence and temporal expression of glial fibrillary acidic protein (GFAP) mRNA following cerebral injury.
- To correlate GFAP mRNA expression with GFAP protein detection using immunocytochemical methods.
- To elucidate the early molecular response of astrocytes to brain trauma.
Main Methods:
- Cerebral freeze-injury model induced in mice.
- Localization of GFAP mRNA using S35-labeled riboprobes.
- Detection of GFAP immunoreactivity via immunocytochemical techniques.
- Quantitative digital image analysis and dark-field microscopy for mRNA and protein assessment.
Main Results:
- GFAP mRNA levels increased in the cortex surrounding the injury within 6 hours, peaking at 4-5 days, and persisting up to 14 days.
- Enhanced mRNA expression was observed in adjacent cortical areas, subpial regions, and corpus callosum, correlating with post-injury edema.
- GFAP protein became detectable 24-48 hours after injury, following the mRNA upregulation.
Conclusions:
- Astrocytes exhibit a rapid response to injury, with early and significant upregulation of GFAP mRNA.
- GFAP mRNA expression precedes the detectable synthesis of GFAP protein, indicating a temporal cascade in astrocyte activation.
- This study provides insights into the molecular mechanisms underlying astrocyte reactivity and potential therapeutic targets in brain injury.
