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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

ED1+ cells invasion into the spinal cords of immunized animals.(A) Prominent inflammatory infiltrates were detected in white and gray matter in immunized animals, where numerous ED1+ cells (green) were present infiltrates and non-infiltrated regions, as well. Control sections did not display noticeable ED1 immunoreactivity. (B) The percentage of ED1+ cells among white matter and gray matter cells in whole spinal cord (all) or within infiltrates or in non-infiltrated regions is presented as mean + SEM. (C) ED1+ cells (red) and Iba1+ cells (green) were present in infiltrated and non-infiltrated regions. Both single-positive and double-positive cells were observed. WM, white matter; GM, gray matter. *p < 0.05 represents statistically significant differences between infiltrates and non-infiltrated regions. Scale bars are 20 µm.
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fig-2: ED1+ cells invasion into the spinal cords of immunized animals.(A) Prominent inflammatory infiltrates were detected in white and gray matter in immunized animals, where numerous ED1+ cells (green) were present infiltrates and non-infiltrated regions, as well. Control sections did not display noticeable ED1 immunoreactivity. (B) The percentage of ED1+ cells among white matter and gray matter cells in whole spinal cord (all) or within infiltrates or in non-infiltrated regions is presented as mean + SEM. (C) ED1+ cells (red) and Iba1+ cells (green) were present in infiltrated and non-infiltrated regions. Both single-positive and double-positive cells were observed. WM, white matter; GM, gray matter. *p < 0.05 represents statistically significant differences between infiltrates and non-infiltrated regions. Scale bars are 20 µm.

Mentions: While ED1+ cells were hardly detectable in the spinal cords of non-immunized rats, numerous positive cells were visible in the spinal cords at the peak of EAE (Fig. 2A). ED1+ cells were present in white and gray matter, both among infiltrating cells and in non-infiltrated regions. The observed high percentage of ED1+ cells, around 40% (Table 1 and bar graph in Fig. 2B), in the region of high infiltration is in accordance with our previous observation of the cellular composition of the infiltrates (Miljković et al., 2011). At the same time, a relatively high percentage of ED1+ cells (around 25%) was observed in non-infiltrated regions. Nevertheless, the number of ED1+ cells was significantly higher in infiltrated than in non-infiltrated regions. No difference was detected between white matter and gray matter irrespectively if infiltrated or non-infiltrated regions were compared. Spinal cord sections were also stained for Iba1 and it was shown that neither all Iba1 cells in non-infiltrated regions were positive for ED1+, nor all ED1+ cells within infiltrates were Iba1 positive (Fig. 2C). Thus, activated macrophages/microglia were present throughout the spinal cord, possibly as a consequence of local activation of microglia, as well as of infiltration of macrophages.


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)

ED1+ cells invasion into the spinal cords of immunized animals.(A) Prominent inflammatory infiltrates were detected in white and gray matter in immunized animals, where numerous ED1+ cells (green) were present infiltrates and non-infiltrated regions, as well. Control sections did not display noticeable ED1 immunoreactivity. (B) The percentage of ED1+ cells among white matter and gray matter cells in whole spinal cord (all) or within infiltrates or in non-infiltrated regions is presented as mean + SEM. (C) ED1+ cells (red) and Iba1+ cells (green) were present in infiltrated and non-infiltrated regions. Both single-positive and double-positive cells were observed. WM, white matter; GM, gray matter. *p < 0.05 represents statistically significant differences between infiltrates and non-infiltrated regions. Scale bars are 20 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig-2: ED1+ cells invasion into the spinal cords of immunized animals.(A) Prominent inflammatory infiltrates were detected in white and gray matter in immunized animals, where numerous ED1+ cells (green) were present infiltrates and non-infiltrated regions, as well. Control sections did not display noticeable ED1 immunoreactivity. (B) The percentage of ED1+ cells among white matter and gray matter cells in whole spinal cord (all) or within infiltrates or in non-infiltrated regions is presented as mean + SEM. (C) ED1+ cells (red) and Iba1+ cells (green) were present in infiltrated and non-infiltrated regions. Both single-positive and double-positive cells were observed. WM, white matter; GM, gray matter. *p < 0.05 represents statistically significant differences between infiltrates and non-infiltrated regions. Scale bars are 20 µm.
Mentions: While ED1+ cells were hardly detectable in the spinal cords of non-immunized rats, numerous positive cells were visible in the spinal cords at the peak of EAE (Fig. 2A). ED1+ cells were present in white and gray matter, both among infiltrating cells and in non-infiltrated regions. The observed high percentage of ED1+ cells, around 40% (Table 1 and bar graph in Fig. 2B), in the region of high infiltration is in accordance with our previous observation of the cellular composition of the infiltrates (Miljković et al., 2011). At the same time, a relatively high percentage of ED1+ cells (around 25%) was observed in non-infiltrated regions. Nevertheless, the number of ED1+ cells was significantly higher in infiltrated than in non-infiltrated regions. No difference was detected between white matter and gray matter irrespectively if infiltrated or non-infiltrated regions were compared. Spinal cord sections were also stained for Iba1 and it was shown that neither all Iba1 cells in non-infiltrated regions were positive for ED1+, nor all ED1+ cells within infiltrates were Iba1 positive (Fig. 2C). Thus, activated macrophages/microglia were present throughout the spinal cord, possibly as a consequence of local activation of microglia, as well as of infiltration of macrophages.

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