Characterization of Photochemically Induced Spinal Cord Injury in the Rat by Light and Electron Microscopy

Bunge, Mary Bartlett; Holets, Vicky R.; Bates, Margaret L.; Clarke, Theresa S.; Watson, Brant D.

doi:10.1006/exnr.1994.1082

Cited by 95 publications

(54 citation statements)

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“…Partial lesions that spare some pathways provide a potential substrate for subsequent spontaneous plasticity in the form of sprouting of spared axons or modified use of spared projections, which could lead to functional improvement. In the case of SCI, a component of the functional deficit after injury is thought to be attributable to demyelination of spared axons (Griffiths and McCulloch, 1983;Waxman, 1992;Bunge et al, 1994;Cao et al, 2001), and the present findings suggest that remyelination of spared projections by newly generated oligodendrocytes could contribute to recovery. Previous studies suggest that embryonic stem cells, when implanted into the spinal cord, differentiate into oligodendrocytes and remyelinate host axons (Keirstead et al, 2005).…”

Section: Discussionsupporting

confidence: 49%

Endogenous Neurogenesis Replaces Oligodendrocytes and Astrocytes after Primate Spinal Cord Injury

Yang¹,

Lu²,

McKay³

et al. 2006

J. Neurosci.

146

123

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Neurogenesis has been described in various regions of the CNS throughout life. We examined the extent of natural cell division and replacement from 7 weeks to 7 months after cervical spinal cord injury in four adult rhesus monkeys. Bromodeoxyuridine (BrdU) injections revealed an increase of Ͼ80-fold in the number of newly divided cells in the primate spinal cord after injury, with an average of 725,000 BrdU-labeled cells identified per monkey in the immediate injury zone. By 7 months after injury, 15% of these new cells expressed mature markers of oligodendrocytes and 12% expressed mature astrocytic markers. Newly born oligodendrocytes were present in zones of injury-induced demyelination and appeared to ensheath or remyelinate host axons. Thus, cell replacement is an extensive natural compensatory response to injury in the primate spinal cord that contributes to neural repair and is a potential target for therapeutic enhancement.

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Section: Discussionsupporting

confidence: 49%

Endogenous Neurogenesis Replaces Oligodendrocytes and Astrocytes after Primate Spinal Cord Injury

Yang¹,

Lu²,

McKay³

et al. 2006

J. Neurosci.

146

123

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“…These LacZ-expressing OECs were not observed directly associating with myelinated or unmyelinated axons. Rather, numerous myelinated and unmyelinated axons were associated with glia possessing a distinct basal lamina and a nucleus with prominent chromatin clumping beneath the nuclear envelope, two characteristic features of Schwann cells (47). Most importantly, the cellular cytoplasm associated with these myelinated and unmyelinated axons did not possess Bluogal reaction product (Figs.…”

Section: Resultsmentioning

confidence: 99%

LacZ -expressing olfactory ensheathing cells do not associate with myelinated axons after implantation into the compressed spinal cord

Boyd

Lee

Skihar

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Studies have shown that implanting olfactory ensheathing cells (OECs) may be a promising therapeutic strategy to promote functional recovery after spinal cord injury. Several fundamental questions remain, however, regarding their in vivo interactions in the damaged spinal cord. We have induced a clip compression injury at the T10 level of the spinal cord in adult rats. After a delay of 1 week, OECs isolated from embryonic day 18 rats were implanted into the cystic cavity that had formed at the site of injury. Before implantation, OECs were infected with a LacZ-expressing retrovirus. At 3 weeks after implantation, LacZ-expressing OECs survived the implantation procedure and remained localized to the cystic cavity. At the electron microscopic level, the cystic cavity had clusters of LacZ-expressing OECs and numerous Schwann cells lacking LacZ expression. Although labeled OECs made no direct contact with axons, unlabeled Schwann cells were associated with either a single myelinated axon or multiple unmyelinated axons. Positively labeled OEC processes often enveloped multiple Schwann cellaxon units. These observations suggest that the role of OECs as the primary mediators of the beneficial effects on axon growth, myelination, and functional recovery after spinal cord injury may require re-evaluation.

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“…described previously 23 and was examined and photographed in a TEM (model CM-10, Philips Research Laboratories) operated at 60 or 80 kV.…”

Section: Tem Analysismentioning

confidence: 99%

Cerebral Blood Flow Restoration and Reperfusion Injury After Ultraviolet Laser–Facilitated Middle Cerebral Artery Recanalization in Rat Thrombotic Stroke

Watson

Prado

Veloso

et al. 2002

Stroke

Self Cite

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Background and Purpose-A reversible model of focal thrombotic stroke was developed in the rat and examined for histological evidence of reperfusion injury after clinically relevant times of recanalization. Methods-The distal middle cerebral artery of 28 male Sprague-Dawley rats was occluded by 562-nm laser-driven photothrombosis for 0.5, 2, and 3 hours or permanently (each nϭ7) and was recanalized by 355-nm UV laser irradiation. Occlusive material was examined by transmission electron microscopy. Cortical cerebral blood flow was monitored by laser-Doppler flowmetry. Brain infarcts were examined histologically at 3 days. Results-After occlusion, cortical cerebral blood flow was reduced to 33Ϯ4% of baseline for all groups and was restored to 82Ϯ9%, 75Ϯ3%, and 93Ϯ7% of baseline for the 0.5-, 2-, and 3-hour groups, respectively, following recanalization after 29Ϯ8, 38Ϯ20, and 70Ϯ33 minutes of UV laser irradiation. The thrombotic occlusion contained compactly aggregated platelets but no fibrin, with length (1.2 to 1.8 mm) proportional to the ischemic period. During recanalization, microchannels containing erythrocytes and scattered leukocytes and bordered by intact disaggregated platelets infiltrated the thrombus. Infarct volumes (mm 3 ) at 3 days were 12Ϯ3 for the permanent case and 8Ϯ4, 24Ϯ3, and 30Ϯ9 for the 0.5-, 2-, and 3-hour cases, respectively, thus demonstrating reperfusion injury histologically in the latter 2 groups. No hemorrhage was seen. Conclusions-UV laser-facilitated dissolution of a conventionally refractory platelet thrombus provides a novel and effective method for restoring blood flow without hemorrhagic complications during thrombotic stroke. This was the first observation of histologically confirmed reperfusion injury in such a model.

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Characterization of Photochemically Induced Spinal Cord Injury in the Rat by Light and Electron Microscopy

Cited by 95 publications

References 0 publications

Endogenous Neurogenesis Replaces Oligodendrocytes and Astrocytes after Primate Spinal Cord Injury

Endogenous Neurogenesis Replaces Oligodendrocytes and Astrocytes after Primate Spinal Cord Injury

LacZ -expressing olfactory ensheathing cells do not associate with myelinated axons after implantation into the compressed spinal cord

Cerebral Blood Flow Restoration and Reperfusion Injury After Ultraviolet Laser–Facilitated Middle Cerebral Artery Recanalization in Rat Thrombotic Stroke

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