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Remodeling the Dendritic Spines in the Hindlimb Representation of the Sensory Cortex after Spinal Cord Hemisection in Mice.

Zhang K, Zhang J, Zhou Y, Chen C, Li W, Ma L, Zhang L, Zhao J, Gan W, Zhang L, Tang P - PLoS ONE (2015)

Bottom Line: In comparison to the control group and contralateral cortex in the SCI group, the re-emerging rate of eliminated spines in ipsilateral cortex of the SCI group decreased significantly.The stable rates of newly formed spines in bilateral cortices of the SCI group decreased from two weeks to one month.In addition, it also made the new formed spines unstable.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedics, General Hospital of Chinese PLA, Beijing, 100853, People's Republic of China.

ABSTRACT
Spinal cord injury (SCI) can induce remodeling of multiple levels of the cerebral cortex system especially in the sensory cortex. The aim of this study was to assess, in vivo and bilaterally, the remodeling of dendritic spines in the hindlimb representation of the sensory cortex after spinal cord hemisection. Thy1-YFP transgenic mice were randomly divided into the control group and the SCI group, and the spinal vertebral plates (T11-T12) of all mice were excised. Next, the left hemisphere of the spinal cord (T12) was hemisected in the SCI group. The hindlimb representations of the sensory cortex in both groups were imaged bilaterally on the day before (0d), and three days (3d), two weeks (2w), and one month (1m) after the SCI. The rates of stable, newly formed, and eliminated spines were calculated by comparing images of individual dendritic spine in the same areas at different time points. In comparison to the control group, the rate of newly formed spines in the contralateral sensory cortex of the SCI group increased at three days and two weeks after injury. The rates of eliminated spines in the bilateral sensory cortices increased and the rate of stable spines in the bilateral cortices declined at two weeks and one month. From three days to two weeks, the stable rates of bilaterally stable spines in the SCI group decreased. In comparison to the control group and contralateral cortex in the SCI group, the re-emerging rate of eliminated spines in ipsilateral cortex of the SCI group decreased significantly. The stable rates of newly formed spines in bilateral cortices of the SCI group decreased from two weeks to one month. We found that the remodeling in the hindlimb representation of the sensory cortex after spinal cord hemisection occurred bilaterally. This remodeling included eliminating spines and forming new spines, as well as changing the reorganized regions of the brain cortex after the SCI over time. Soon after the SCI, the cortex was remodeled by increasing spine formation in the contralateral cortex. Then it was remodeled prominently by eliminating spines of bilateral cortices. Spinal cord hemisection also caused traditional stable spines to become unstable and led the eliminated spines even more hard to recur especially in the ipsilateral cortex of the SCI group. In addition, it also made the new formed spines unstable.

No MeSH data available.


Related in: MedlinePlus

Dendritic spines of YFP mice longitudinally observed by two-photon microscopy.(A) Schematic of the imaging of the cortex using the two-photon carrier. (B) Locating the observation site by viewing vasculature under the thinned skull. (C) In vivo imaging the primary sensory cortex at 25× magnification, the dendritic spines and axons appear clearly. (D–G) Magnified images of (C) at (D) day 0 and (E) day 4, at (F) two weeks, and at (G) one month. Arrows: dendritic spines observed at the indicated four time points. Arrowheads: dendritic spines that disappeared on the fourth day. #: dendritic spines that were newly formed by the fourth day and remained at two weeks and one month. ☆: dendritic spines that were newly formed by the fourth day, but disappeared at two weeks. Scale bars: 0.5mm(B),10 μm (C), 2 μm (D, E, F, G).
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pone.0132077.g003: Dendritic spines of YFP mice longitudinally observed by two-photon microscopy.(A) Schematic of the imaging of the cortex using the two-photon carrier. (B) Locating the observation site by viewing vasculature under the thinned skull. (C) In vivo imaging the primary sensory cortex at 25× magnification, the dendritic spines and axons appear clearly. (D–G) Magnified images of (C) at (D) day 0 and (E) day 4, at (F) two weeks, and at (G) one month. Arrows: dendritic spines observed at the indicated four time points. Arrowheads: dendritic spines that disappeared on the fourth day. #: dendritic spines that were newly formed by the fourth day and remained at two weeks and one month. ☆: dendritic spines that were newly formed by the fourth day, but disappeared at two weeks. Scale bars: 0.5mm(B),10 μm (C), 2 μm (D, E, F, G).

Mentions: The hindlimb representation of the sensory cortex region was located 1.4 mm posterior to the bregma and within 1.7 mm laterally from the midline. Those regions have been identified by microstimulation as the location of the hindlimb sensory representative region in the same mouse strain as that used in the present experiments. The hindlimb representation region was confirmed by cytochrome oxidase staining. The imaging window used here was small (~200 μm in diameter, Fig 2B).We used stereotaxic coordinates of previously mapped hindlimb sensory regions for guidance into studying the dynamics of the dendritic spine in the sensory cortex [33,38–40].The vasculature pattern that was indicated by anatomical microscope (Fig 2B) and two-photo microscope (Fig 3B) remained stable for months to years and could be used as a landmark to relocate the image area in the sensory cortex at three subsequent time points.


Remodeling the Dendritic Spines in the Hindlimb Representation of the Sensory Cortex after Spinal Cord Hemisection in Mice.

Zhang K, Zhang J, Zhou Y, Chen C, Li W, Ma L, Zhang L, Zhao J, Gan W, Zhang L, Tang P - PLoS ONE (2015)

Dendritic spines of YFP mice longitudinally observed by two-photon microscopy.(A) Schematic of the imaging of the cortex using the two-photon carrier. (B) Locating the observation site by viewing vasculature under the thinned skull. (C) In vivo imaging the primary sensory cortex at 25× magnification, the dendritic spines and axons appear clearly. (D–G) Magnified images of (C) at (D) day 0 and (E) day 4, at (F) two weeks, and at (G) one month. Arrows: dendritic spines observed at the indicated four time points. Arrowheads: dendritic spines that disappeared on the fourth day. #: dendritic spines that were newly formed by the fourth day and remained at two weeks and one month. ☆: dendritic spines that were newly formed by the fourth day, but disappeared at two weeks. Scale bars: 0.5mm(B),10 μm (C), 2 μm (D, E, F, G).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4489092&req=5

pone.0132077.g003: Dendritic spines of YFP mice longitudinally observed by two-photon microscopy.(A) Schematic of the imaging of the cortex using the two-photon carrier. (B) Locating the observation site by viewing vasculature under the thinned skull. (C) In vivo imaging the primary sensory cortex at 25× magnification, the dendritic spines and axons appear clearly. (D–G) Magnified images of (C) at (D) day 0 and (E) day 4, at (F) two weeks, and at (G) one month. Arrows: dendritic spines observed at the indicated four time points. Arrowheads: dendritic spines that disappeared on the fourth day. #: dendritic spines that were newly formed by the fourth day and remained at two weeks and one month. ☆: dendritic spines that were newly formed by the fourth day, but disappeared at two weeks. Scale bars: 0.5mm(B),10 μm (C), 2 μm (D, E, F, G).
Mentions: The hindlimb representation of the sensory cortex region was located 1.4 mm posterior to the bregma and within 1.7 mm laterally from the midline. Those regions have been identified by microstimulation as the location of the hindlimb sensory representative region in the same mouse strain as that used in the present experiments. The hindlimb representation region was confirmed by cytochrome oxidase staining. The imaging window used here was small (~200 μm in diameter, Fig 2B).We used stereotaxic coordinates of previously mapped hindlimb sensory regions for guidance into studying the dynamics of the dendritic spine in the sensory cortex [33,38–40].The vasculature pattern that was indicated by anatomical microscope (Fig 2B) and two-photo microscope (Fig 3B) remained stable for months to years and could be used as a landmark to relocate the image area in the sensory cortex at three subsequent time points.

Bottom Line: In comparison to the control group and contralateral cortex in the SCI group, the re-emerging rate of eliminated spines in ipsilateral cortex of the SCI group decreased significantly.The stable rates of newly formed spines in bilateral cortices of the SCI group decreased from two weeks to one month.In addition, it also made the new formed spines unstable.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedics, General Hospital of Chinese PLA, Beijing, 100853, People's Republic of China.

ABSTRACT
Spinal cord injury (SCI) can induce remodeling of multiple levels of the cerebral cortex system especially in the sensory cortex. The aim of this study was to assess, in vivo and bilaterally, the remodeling of dendritic spines in the hindlimb representation of the sensory cortex after spinal cord hemisection. Thy1-YFP transgenic mice were randomly divided into the control group and the SCI group, and the spinal vertebral plates (T11-T12) of all mice were excised. Next, the left hemisphere of the spinal cord (T12) was hemisected in the SCI group. The hindlimb representations of the sensory cortex in both groups were imaged bilaterally on the day before (0d), and three days (3d), two weeks (2w), and one month (1m) after the SCI. The rates of stable, newly formed, and eliminated spines were calculated by comparing images of individual dendritic spine in the same areas at different time points. In comparison to the control group, the rate of newly formed spines in the contralateral sensory cortex of the SCI group increased at three days and two weeks after injury. The rates of eliminated spines in the bilateral sensory cortices increased and the rate of stable spines in the bilateral cortices declined at two weeks and one month. From three days to two weeks, the stable rates of bilaterally stable spines in the SCI group decreased. In comparison to the control group and contralateral cortex in the SCI group, the re-emerging rate of eliminated spines in ipsilateral cortex of the SCI group decreased significantly. The stable rates of newly formed spines in bilateral cortices of the SCI group decreased from two weeks to one month. We found that the remodeling in the hindlimb representation of the sensory cortex after spinal cord hemisection occurred bilaterally. This remodeling included eliminating spines and forming new spines, as well as changing the reorganized regions of the brain cortex after the SCI over time. Soon after the SCI, the cortex was remodeled by increasing spine formation in the contralateral cortex. Then it was remodeled prominently by eliminating spines of bilateral cortices. Spinal cord hemisection also caused traditional stable spines to become unstable and led the eliminated spines even more hard to recur especially in the ipsilateral cortex of the SCI group. In addition, it also made the new formed spines unstable.

No MeSH data available.


Related in: MedlinePlus