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Involvement of brain-derived neurotrophic factor in time-dependent neurodegeneration in the murine superior colliculus after intravitreal injection of N-methyl-D-aspartate.

Tanaka H, Ito Y, Nakamura S, Shimazawa M, Hara H - Mol. Vis. (2009)

Bottom Line: The number of neuronal nuclear specific protein (NeuN)-immunostained neurons showed a significant decrease in the contralateral SC at both 90 and 180 days after intravitreal NMDA injection.In contrast, the ipsilateral SC displayed no significant change in the number of NeuN-positive cells.Hence, these findings may provide useful information concerning the pathological mechanisms of several disorders accompanied by retinal degeneration.

View Article: PubMed Central - PubMed

Affiliation: 1Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu, Japan.

ABSTRACT

Purpose: To clarify the effects on the visual pathway that occur following retinal damage, we examined the morphological alterations present in the superior colliculus (SC) after N-methyl-D-aspartate (NMDA)-induced retinal damage in mice.

Methods: NMDA was injected into the vitreous body of the left eye in mice to induce retinal damage. The time-dependent neuronal degeneration in the SC was assessed using immunohistochemistry.

Results: The number of neuronal nuclear specific protein (NeuN)-immunostained neurons showed a significant decrease in the contralateral SC at both 90 and 180 days after intravitreal NMDA injection. In contrast, the ipsilateral SC displayed no significant change in the number of NeuN-positive cells. An increase in glial fibrillary acid protein (GFAP) immunoreactivity was observed in the contralateral SC at 7, 30, and 90 days after NMDA injection and in the ipsilateral SC at 7 days, while brain-derived neurotrophic factor (BDNF) expression was increased in the contralateral SC at 30 and 90 days. In the contralateral SC, some GFAP-positive astroglial cells also exhibited BDNF at 30 days after NMDA injection.

Conclusions: Evidence of time-dependent morphological neuronal degeneration along the retinocollicular pathway from the retina to the SC was detected at 90 and 180 days, but not at 30 days, after NMDA-induced retinal damage. This neurodegeneration was preceded by an increase in BDNF expression in the SC, specifically at 30 and 90 days after NMDA injection. Hence, these findings may provide useful information concerning the pathological mechanisms of several disorders accompanied by retinal degeneration.

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BDNF-positive cells of sections of the SC. A: Representative microphotographs of the superior colliculus (SC; the contralateral side and the ipsilateral side) are shown for the control group (untreated) 3, 7, 30, 90, and 180 days after N-methyl-D-aspartate (NMDA) injection. The scale bar represents 30 µm. B: Representative photographs show brain-derived neurotrophic factor (BDNF) and neuronal nuclear specific protein (NeuN) immunostaining, and BDNF/NeuN double-immunostaining of the contralateral SC at 30 days after intravitreal NMDA injection in mice. Some BDNF-expressing cells were colocalized with NeuN-positive neuronal cells, as indicated by the yellow color. The scale bar represents 20 µm. C: The average number of BDNF immunopositive puncta was counted in the SC. Each value represents the mean±SEM (n=3). The asterisk indicates p<0.05, while the double asterisk represents p<0.01 versus control (untreated mice; Dunnett’s test).
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f4: BDNF-positive cells of sections of the SC. A: Representative microphotographs of the superior colliculus (SC; the contralateral side and the ipsilateral side) are shown for the control group (untreated) 3, 7, 30, 90, and 180 days after N-methyl-D-aspartate (NMDA) injection. The scale bar represents 30 µm. B: Representative photographs show brain-derived neurotrophic factor (BDNF) and neuronal nuclear specific protein (NeuN) immunostaining, and BDNF/NeuN double-immunostaining of the contralateral SC at 30 days after intravitreal NMDA injection in mice. Some BDNF-expressing cells were colocalized with NeuN-positive neuronal cells, as indicated by the yellow color. The scale bar represents 20 µm. C: The average number of BDNF immunopositive puncta was counted in the SC. Each value represents the mean±SEM (n=3). The asterisk indicates p<0.05, while the double asterisk represents p<0.01 versus control (untreated mice; Dunnett’s test).

Mentions: The specificity of the antibody against BDNF employed in this experiment has been characterized using immunohistochemistry and western blotting [24]. The antibody was unique to BDNF and did not detect other neurotrophins. To examine the time-dependent changes in BDNF expression, we performed immunohistostaining (Figure 4). In the control mice, BDNF-positive cells were observed in SC (Figure 4A), and they were significantly increased (versus control) in the contralateral SC at 30 and 90 days after NMDA injection (Figure 4C). Similarly, a slight increase (versus control) was observed in the ipsilateral SC at 90 and 180 days (Figure 4C). To identify BDNF-positive cells, we performed double immunofluorescence for BDNF and NeuN using the SC sections. Some NeuN-positive neuronal cells expressed BDNF at 30 days after NMDA injection (Figure 4B). No morphological differences in the SC were observed among the control and sham-treated mice (data not shown).


Involvement of brain-derived neurotrophic factor in time-dependent neurodegeneration in the murine superior colliculus after intravitreal injection of N-methyl-D-aspartate.

Tanaka H, Ito Y, Nakamura S, Shimazawa M, Hara H - Mol. Vis. (2009)

BDNF-positive cells of sections of the SC. A: Representative microphotographs of the superior colliculus (SC; the contralateral side and the ipsilateral side) are shown for the control group (untreated) 3, 7, 30, 90, and 180 days after N-methyl-D-aspartate (NMDA) injection. The scale bar represents 30 µm. B: Representative photographs show brain-derived neurotrophic factor (BDNF) and neuronal nuclear specific protein (NeuN) immunostaining, and BDNF/NeuN double-immunostaining of the contralateral SC at 30 days after intravitreal NMDA injection in mice. Some BDNF-expressing cells were colocalized with NeuN-positive neuronal cells, as indicated by the yellow color. The scale bar represents 20 µm. C: The average number of BDNF immunopositive puncta was counted in the SC. Each value represents the mean±SEM (n=3). The asterisk indicates p<0.05, while the double asterisk represents p<0.01 versus control (untreated mice; Dunnett’s test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2664844&req=5

f4: BDNF-positive cells of sections of the SC. A: Representative microphotographs of the superior colliculus (SC; the contralateral side and the ipsilateral side) are shown for the control group (untreated) 3, 7, 30, 90, and 180 days after N-methyl-D-aspartate (NMDA) injection. The scale bar represents 30 µm. B: Representative photographs show brain-derived neurotrophic factor (BDNF) and neuronal nuclear specific protein (NeuN) immunostaining, and BDNF/NeuN double-immunostaining of the contralateral SC at 30 days after intravitreal NMDA injection in mice. Some BDNF-expressing cells were colocalized with NeuN-positive neuronal cells, as indicated by the yellow color. The scale bar represents 20 µm. C: The average number of BDNF immunopositive puncta was counted in the SC. Each value represents the mean±SEM (n=3). The asterisk indicates p<0.05, while the double asterisk represents p<0.01 versus control (untreated mice; Dunnett’s test).
Mentions: The specificity of the antibody against BDNF employed in this experiment has been characterized using immunohistochemistry and western blotting [24]. The antibody was unique to BDNF and did not detect other neurotrophins. To examine the time-dependent changes in BDNF expression, we performed immunohistostaining (Figure 4). In the control mice, BDNF-positive cells were observed in SC (Figure 4A), and they were significantly increased (versus control) in the contralateral SC at 30 and 90 days after NMDA injection (Figure 4C). Similarly, a slight increase (versus control) was observed in the ipsilateral SC at 90 and 180 days (Figure 4C). To identify BDNF-positive cells, we performed double immunofluorescence for BDNF and NeuN using the SC sections. Some NeuN-positive neuronal cells expressed BDNF at 30 days after NMDA injection (Figure 4B). No morphological differences in the SC were observed among the control and sham-treated mice (data not shown).

Bottom Line: The number of neuronal nuclear specific protein (NeuN)-immunostained neurons showed a significant decrease in the contralateral SC at both 90 and 180 days after intravitreal NMDA injection.In contrast, the ipsilateral SC displayed no significant change in the number of NeuN-positive cells.Hence, these findings may provide useful information concerning the pathological mechanisms of several disorders accompanied by retinal degeneration.

View Article: PubMed Central - PubMed

Affiliation: 1Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu, Japan.

ABSTRACT

Purpose: To clarify the effects on the visual pathway that occur following retinal damage, we examined the morphological alterations present in the superior colliculus (SC) after N-methyl-D-aspartate (NMDA)-induced retinal damage in mice.

Methods: NMDA was injected into the vitreous body of the left eye in mice to induce retinal damage. The time-dependent neuronal degeneration in the SC was assessed using immunohistochemistry.

Results: The number of neuronal nuclear specific protein (NeuN)-immunostained neurons showed a significant decrease in the contralateral SC at both 90 and 180 days after intravitreal NMDA injection. In contrast, the ipsilateral SC displayed no significant change in the number of NeuN-positive cells. An increase in glial fibrillary acid protein (GFAP) immunoreactivity was observed in the contralateral SC at 7, 30, and 90 days after NMDA injection and in the ipsilateral SC at 7 days, while brain-derived neurotrophic factor (BDNF) expression was increased in the contralateral SC at 30 and 90 days. In the contralateral SC, some GFAP-positive astroglial cells also exhibited BDNF at 30 days after NMDA injection.

Conclusions: Evidence of time-dependent morphological neuronal degeneration along the retinocollicular pathway from the retina to the SC was detected at 90 and 180 days, but not at 30 days, after NMDA-induced retinal damage. This neurodegeneration was preceded by an increase in BDNF expression in the SC, specifically at 30 and 90 days after NMDA injection. Hence, these findings may provide useful information concerning the pathological mechanisms of several disorders accompanied by retinal degeneration.

Show MeSH
Related in: MedlinePlus