title: Effects of epidural compression on stellate neurons and thalamocortical afferent fibers in the rat primary somatosensory cortex.
abstract: A number of neurological disorders such as epidural hematoma can cause compression of cerebral cortex. We here tested the hypothesis that sustained compression of primary somatosensory cortex may affect stellate neurons and thalamocortical afferent (TCA) fibers. A rat model with barrel cortex subjected to bead epidural compression was used. Golgi-Cox staining analyses showed the shrinkage of dendritic arbors and the stripping of dendritic spines of stellate neurons for at least 3 months post-lesion. Anterograde tracing analyses exhibited a progressive decline of TCA fiber density in barrel field for 6 months post-lesion. Due to the abrupt decrease of TCA fiber density at 3 days after compression, we further used electron microscopy to investigate the ultrastructure of TCA fibers at this time. Some TCA fiber terminal profiles with dissolved or darkened mitochondria and fewer synaptic vesicles were distorted and broken. Furthermore, the disruption of mitochondria and myelin sheath was observed in some myelinated TCA fibers. In addition, expressions of oxidative markers 3-nitrotyrosine and 4-hydroxynonenal were elevated in barrel field post-lesion. Treatment of antioxidant ascorbic acid or apocynin was able to reverse the increase of oxidative stress and the decline of TCA fiber density, rather than the shrinkage of dendrites and the stripping of dendritic spines of stellate neurons post-lesion. Together, these results indicate that sustained epidural compression of primary somatosensory cortex affects the TCA fibers and the dendrites of stellate neurons for a prolonged period. In addition, oxidative stress is responsible for the reduction of TCA fiber density in barrels rather than the shrinkage of dendrites and the stripping of dendritic spines of stellate neurons.
authors.affiliation: Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan.
authors.forename: Tzu-Yin
authors.initials: TY
authors.lastname: Yeh
authors.affiliation: Department of Anatomy, Tzu Chi University, Hualien, Taiwan, Institute of Physiological and Anatomical Medicine, Tzu Chi University, Hualien, Taiwan.
authors.forename: Guo-Fang
authors.initials: GF
authors.lastname: Tseng
authors.affiliation: Department of Neurology, Taichung Tzu Chi Hospital, Taichung, Taiwan.
authors.forename: Chi-Yu
authors.initials: CY
authors.lastname: Tseng
authors.affiliation: Institute of Physiological and Anatomical Medicine, Tzu Chi University, Hualien, Taiwan.
authors.forename: Yung-Hsin
authors.initials: YH
authors.lastname: Huang
authors.affiliation: Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan, Department of Anatomy, Tzu Chi University, Hualien, Taiwan, Institute of Physiological and Anatomical Medicine, Tzu Chi University, Hualien, Taiwan, peihsin@mail.tcu.edu.tw.
authors.forename: Pei-Hsin
authors.initials: PH
authors.lastname: Liu
mesh_terms: D000098:Acetophenones / Q000627:therapeutic use; D000344:Afferent Pathways / Q000473:pathology*; D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000627:therapeutic use; D001205:Ascorbic Acid / Q000627:therapeutic use; D001710:Biotin / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D001930:Brain Injuries / Q000188:drug therapy / Q000473:pathology*; D003712:Dendrites / Q000473:pathology / Q000648:ultrastructure; D003911:Dextrans / Q000493:pharmacokinetics; D004195:Disease Models, Animal; D003576:Electron Transport Complex IV / Q000378:metabolism; D004824:Epidural Space / Q000502:physiology; D007839:Functional Laterality; D008297:Male; D009474:Neurons / Q000473:pathology* / Q000648:ultrastructure; D018384:Oxidative Stress / Q000502:physiology; D051381:Rats; D013003:Somatosensory Cortex / Q000293:injuries / Q000473:pathology*; D013788:Thalamus / Q000473:pathology* / Q000648:ultrastructure; D013997:Time Factors; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000098:Acetophenones; D000447:Aldehydes; D000975:Antioxidants; D003911:Dextrans; C076397:biotinylated dextran amine; C002744:3-nitrotyrosine; D014443:Tyrosine; D001710:Biotin; C056165:acetovanillone; D003576:Electron Transport Complex IV; C027576:4-hydroxy-2-nonenal; D001205:Ascorbic Acid