Removal of a compressive mass causes a transient disruption of blood-brain barrier but a long-term recovery of spiny stellate neurons in the rat somatosensory cortex

Article type: Research Article

Authors: Yeh, Tzu-Yin^a | Liu, Pei-Hsin^{a; b; *}

Affiliations: [a] Department of Anatomy, Tzu Chi University, Hualien, Taiwan | [b] Medical Physiology, Tzu Chi University, Hualien, Taiwan

Correspondence: [*] Corresponding author: Pei-Hsin LIU, Ph.D., Department of Anatomy, Tzu Chi University, No. 701, Section 3, Chung-Yang Road, Hualien 97004, Taiwan. Tel.: +886 3 8565301 2148; Fax: +886 3 8564641; E-mail: [email protected].

Abstract: Background:In the cranial cavity, a space-occupying mass such as epidural hematoma usually leads to compression of brain. Removal of a large compressive mass under the cranial vault is critical to the patients. Objective:The purpose of this study was to examine whether and to what extent epidural decompression of the rat primary somatosensory cortex affects the underlying microvessels, spiny stellate neurons and their afferent fibers. Methods:Rats received epidural decompression with preceding 1-week compression by implantation of a bead. The thickness of cortex was measured using brain coronal sections. The permeability of blood-brain barrier (BBB) was assessed by Evans Blue and immunoglobulin G extravasation. The dendrites and dendritic spines of the spiny stellate neurons were revealed by Golgi-Cox staining and analyzed. In addition, the thalamocortical afferent (TCA) fibers in the cortex were illustrated using anterograde tracing and examined. Results:The cortex gradually regained its thickness over time and became comparable to the sham group at 3 days after decompression. Although the diameter of cortical microvessels were unaltered, a transient disruption of the BBB was observed at 6 hours and 1 day after decompression. Nevertheless, no brain edema was detected. In contrast, the dendrites and dendritic spines of the spiny stellate neurons and the TCA fibers were markedly restored from 2 weeks to 3 months after decompression. Conclusions:Epidural decompression caused a breakdown of the BBB, which was early-occurring and short-lasting. In contrast, epidural decompression facilitated a late-onset and prolonged recovery of the spiny stellate neurons and their afferent fibers.

Keywords: Decompression, stellate neuron, thalamocortical fiber, BBB, dendritic spine, somatosensory cortex

DOI: 10.3233/RNN-201085

Journal: Restorative Neurology and Neuroscience, vol. 39, no. 2, pp. 111-127, 2021