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Cell death of spinal cord ED1(+) cells in a rat model of multiple sclerosis.

Trifunović D, Djedović N, Lavrnja I, Wendrich KS, Paquet-Durand F, Miljković D - PeerJ (2015)

Bottom Line: Our findings suggest that activated macrophages/microglia of gray matter are less susceptible to cell death induction.Thus, further research on the gray matter macrophages/microglia cell death during EAE is warranted.They should be aimed at identification of the reasons for the observed differences and finding suitable ways to stimulate gray matter activated macrophages/microglia death.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Ophthalmic Research, University of Tuebingen , Tuebingen , Germany.

ABSTRACT
Infiltration of macrophages into the central nervous system and activation of microglia are hallmarks of multiple sclerosis and its animal model-experimental autoimmune encephalomyelitis (EAE). Cell death in EAE has been demonstrated as an essential mechanism in the local regulation of the inflammatory reaction, but also as one of the major factors contributing to the destruction of the nervous tissue. The focus of this study was on detection of cell death among ED1(+) cells (macrophages/activated microglia) in the spinal cord of Dark Agouti rats at the peak of EAE. Cell death was assessed using the TUNEL assay and immunostaining for cleaved caspase 3, as markers for cell death in general and "classical" apoptosis, respectively. Major infiltrates of immune cells were detected both in white matter and gray matter of spinal cords in rats at the disease peak. ED1, TUNEL, and caspase 3 positive cells were detected within, but also outside the infiltrates. There were more dying ED1(+) cells in white matter than in gray matter, both in the general population and in infiltrated regions. The observed discrepancy in the proportion of dying ED1(+) cells in spinal cord gray and white matter indicated that in EAE rat macrophages/microglia within gray matter are less prone to cell death induction. This is of special interest in the context of the increasingly appreciated contribution of spinal cord gray matter inflammation to multiple sclerosis pathogenesis. Our findings suggest that activated macrophages/microglia of gray matter are less susceptible to cell death induction. Alternatively, it can be assumed that intrinsic cell death-inductive mechanisms of nervous tissue differ in white and gray matter. Thus, further research on the gray matter macrophages/microglia cell death during EAE is warranted. They should be aimed at identification of the reasons for the observed differences and finding suitable ways to stimulate gray matter activated macrophages/microglia death.

No MeSH data available.


Related in: MedlinePlus

Cell death of ED1+ cells in immunized animals(A) Spinal cord cross-sections of immunized animals were stained for ED1+ cells (red) and for dying cells (green). There were more dying cells among ED1+ cells in white matter compared to gray matter. (B) White and gray matter from immunized rats were also co-stained for ED1+ (red) and cleaved caspase 3 (green) cells. The merged pictures showed cells positive for each of the markers as well as cells positive for both stainings. Inserts represent a higher magnification from infiltrated regions of both white matter and gray matter. (C) Bar graphs represent the percentages of TUNEL positive cells among ED1+ cells in white matter (WM) and gray matter (GM), in whole spinal cord (all), or within infiltrates, or in non-infiltrated regions. (D) The percentage of caspase positive among ED1+ cells showed no statistically significant difference between white matter and gray matter, or between infiltrates and non-infiltrated regions. Quantitative data are presented as mean + SEM. *p < 0.05 represents statistically significant difference between infiltrates vs. non-infiltrated regions or between white matter. Scale bars are 20 µm.
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fig-4: Cell death of ED1+ cells in immunized animals(A) Spinal cord cross-sections of immunized animals were stained for ED1+ cells (red) and for dying cells (green). There were more dying cells among ED1+ cells in white matter compared to gray matter. (B) White and gray matter from immunized rats were also co-stained for ED1+ (red) and cleaved caspase 3 (green) cells. The merged pictures showed cells positive for each of the markers as well as cells positive for both stainings. Inserts represent a higher magnification from infiltrated regions of both white matter and gray matter. (C) Bar graphs represent the percentages of TUNEL positive cells among ED1+ cells in white matter (WM) and gray matter (GM), in whole spinal cord (all), or within infiltrates, or in non-infiltrated regions. (D) The percentage of caspase positive among ED1+ cells showed no statistically significant difference between white matter and gray matter, or between infiltrates and non-infiltrated regions. Quantitative data are presented as mean + SEM. *p < 0.05 represents statistically significant difference between infiltrates vs. non-infiltrated regions or between white matter. Scale bars are 20 µm.

Mentions: Co-staining for ED1 and TUNEL was performed in order to attribute the role of ED1+ cells in spinal cord cell death as the consequence of the immunization. ED1+ cells positive for TUNEL were detected within the infiltrates, as well as in non-infiltrated regions (Figs. 4A–4C). About 40% of all the TUNEL positive cells colocalized with ED1 staining (Table 3). This percentage remained relatively constant both in white matter and gray matter as well as in infiltrates and non-infiltrated regions. However, when the proportion of TUNEL positive cells among ED1+ cells was assessed, a significant difference was detected between white matter and gray matter in general (25.4 ± 3.2 and 17.9 ± 3.1, respectively). Still, the significance was confined only to infiltrated regions of white matter and gray matter (Table 3).


Cell death of spinal cord ED1(+) cells in a rat model of multiple sclerosis.

Trifunović D, Djedović N, Lavrnja I, Wendrich KS, Paquet-Durand F, Miljković D - PeerJ (2015)

Cell death of ED1+ cells in immunized animals(A) Spinal cord cross-sections of immunized animals were stained for ED1+ cells (red) and for dying cells (green). There were more dying cells among ED1+ cells in white matter compared to gray matter. (B) White and gray matter from immunized rats were also co-stained for ED1+ (red) and cleaved caspase 3 (green) cells. The merged pictures showed cells positive for each of the markers as well as cells positive for both stainings. Inserts represent a higher magnification from infiltrated regions of both white matter and gray matter. (C) Bar graphs represent the percentages of TUNEL positive cells among ED1+ cells in white matter (WM) and gray matter (GM), in whole spinal cord (all), or within infiltrates, or in non-infiltrated regions. (D) The percentage of caspase positive among ED1+ cells showed no statistically significant difference between white matter and gray matter, or between infiltrates and non-infiltrated regions. Quantitative data are presented as mean + SEM. *p < 0.05 represents statistically significant difference between infiltrates vs. non-infiltrated regions or between white matter. Scale bars are 20 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581773&req=5

fig-4: Cell death of ED1+ cells in immunized animals(A) Spinal cord cross-sections of immunized animals were stained for ED1+ cells (red) and for dying cells (green). There were more dying cells among ED1+ cells in white matter compared to gray matter. (B) White and gray matter from immunized rats were also co-stained for ED1+ (red) and cleaved caspase 3 (green) cells. The merged pictures showed cells positive for each of the markers as well as cells positive for both stainings. Inserts represent a higher magnification from infiltrated regions of both white matter and gray matter. (C) Bar graphs represent the percentages of TUNEL positive cells among ED1+ cells in white matter (WM) and gray matter (GM), in whole spinal cord (all), or within infiltrates, or in non-infiltrated regions. (D) The percentage of caspase positive among ED1+ cells showed no statistically significant difference between white matter and gray matter, or between infiltrates and non-infiltrated regions. Quantitative data are presented as mean + SEM. *p < 0.05 represents statistically significant difference between infiltrates vs. non-infiltrated regions or between white matter. Scale bars are 20 µm.
Mentions: Co-staining for ED1 and TUNEL was performed in order to attribute the role of ED1+ cells in spinal cord cell death as the consequence of the immunization. ED1+ cells positive for TUNEL were detected within the infiltrates, as well as in non-infiltrated regions (Figs. 4A–4C). About 40% of all the TUNEL positive cells colocalized with ED1 staining (Table 3). This percentage remained relatively constant both in white matter and gray matter as well as in infiltrates and non-infiltrated regions. However, when the proportion of TUNEL positive cells among ED1+ cells was assessed, a significant difference was detected between white matter and gray matter in general (25.4 ± 3.2 and 17.9 ± 3.1, respectively). Still, the significance was confined only to infiltrated regions of white matter and gray matter (Table 3).

Bottom Line: Our findings suggest that activated macrophages/microglia of gray matter are less susceptible to cell death induction.Thus, further research on the gray matter macrophages/microglia cell death during EAE is warranted.They should be aimed at identification of the reasons for the observed differences and finding suitable ways to stimulate gray matter activated macrophages/microglia death.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Ophthalmic Research, University of Tuebingen , Tuebingen , Germany.

ABSTRACT
Infiltration of macrophages into the central nervous system and activation of microglia are hallmarks of multiple sclerosis and its animal model-experimental autoimmune encephalomyelitis (EAE). Cell death in EAE has been demonstrated as an essential mechanism in the local regulation of the inflammatory reaction, but also as one of the major factors contributing to the destruction of the nervous tissue. The focus of this study was on detection of cell death among ED1(+) cells (macrophages/activated microglia) in the spinal cord of Dark Agouti rats at the peak of EAE. Cell death was assessed using the TUNEL assay and immunostaining for cleaved caspase 3, as markers for cell death in general and "classical" apoptosis, respectively. Major infiltrates of immune cells were detected both in white matter and gray matter of spinal cords in rats at the disease peak. ED1, TUNEL, and caspase 3 positive cells were detected within, but also outside the infiltrates. There were more dying ED1(+) cells in white matter than in gray matter, both in the general population and in infiltrated regions. The observed discrepancy in the proportion of dying ED1(+) cells in spinal cord gray and white matter indicated that in EAE rat macrophages/microglia within gray matter are less prone to cell death induction. This is of special interest in the context of the increasingly appreciated contribution of spinal cord gray matter inflammation to multiple sclerosis pathogenesis. Our findings suggest that activated macrophages/microglia of gray matter are less susceptible to cell death induction. Alternatively, it can be assumed that intrinsic cell death-inductive mechanisms of nervous tissue differ in white and gray matter. Thus, further research on the gray matter macrophages/microglia cell death during EAE is warranted. They should be aimed at identification of the reasons for the observed differences and finding suitable ways to stimulate gray matter activated macrophages/microglia death.

No MeSH data available.


Related in: MedlinePlus