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Low dose cranial irradiation-induced cerebrovascular damage is reversible in mice.

Sándor N, Walter FR, Bocsik A, Sántha P, Schilling-Tóth B, Léner V, Varga Z, Kahán Z, Deli MA, Sáfrány G, Hegyesi H - PLoS ONE (2014)

Bottom Line: Blood-brain barrier permeability for Evans blue, body weight and number of peripheral mononuclear and circulating endothelial progenitor cells were evaluated 1, 4 and 26 weeks postirradiation.Endothelial senescence was determined by senescence associated β-galactosidase staining.Extravasation of Evans blue increased in cerebrum and cerebellum in adult mice 1 week and in infant mice 4 weeks postirradiation at all treatment doses.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Radiobiology and Biodosimetry, "Frédéric Joliot-Curie" National Research Institute for Radiobiology and Radiohygiene, Budapest, Hungary; Doctoral Schools of Pathological Sciences, Semmelweis University, Budapest, Hungary.

ABSTRACT

Background: High-dose radiation-induced blood-brain barrier breakdown contributes to acute radiation toxicity syndrome and delayed brain injury, but there are few data on the effects of low dose cranial irradiation. Our goal was to measure blood-brain barrier changes after low (0.1 Gy), moderate (2 Gy) and high (10 Gy) dose irradiation under in vivo and in vitro conditions.

Methodology: Cranial irradiation was performed on 10-day-old and 10-week-old mice. Blood-brain barrier permeability for Evans blue, body weight and number of peripheral mononuclear and circulating endothelial progenitor cells were evaluated 1, 4 and 26 weeks postirradiation. Barrier properties of primary mouse brain endothelial cells co-cultured with glial cells were determined by measurement of resistance and permeability for marker molecules and staining for interendothelial junctions. Endothelial senescence was determined by senescence associated β-galactosidase staining.

Principle findings: Extravasation of Evans blue increased in cerebrum and cerebellum in adult mice 1 week and in infant mice 4 weeks postirradiation at all treatment doses. Head irradiation with 10 Gy decreased body weight. The number of circulating endothelial progenitor cells in blood was decreased 1 day after irradiation with 0.1 and 2 Gy. Increase in the permeability of cultured brain endothelial monolayers for fluorescein and albumin was time- and radiation dose dependent and accompanied by changes in junctional immunostaining for claudin-5, ZO-1 and β-catenin. The number of cultured brain endothelial and glial cells decreased from third day of postirradiation and senescence in endothelial cells increased at 2 and 10 Gy.

Conclusion: Not only high but low and moderate doses of cranial irradiation increase permeability of cerebral vessels in mice, but this effect is reversible by 6 months. In-vitro experiments suggest that irradiation changes junctional morphology, decreases cell number and causes senescence in brain endothelial cells.

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Effect of single dose cranial irradiation on circulating endothelial progenitor cell number.Single head irradiation with 0.1, 2 and 10 Gy doses was performed on 10-week-old adult mice. Circulating endothelial progenitor cell were isolated and cultured from peripheral blood mononuclear cells 1 day, 1, 4 and 26 weeks postirradiation (A). The number of endothelial progenitor cells is presented as colony forming unit/peripheral mononuclear cell ×105/ml blood. Values presented are means ± SD, n = 3–10 from 2–3 separate experiments. Statistical analysis: two-way ANOVA followed by Bonferroni post-test. Statistically significant differences p<0.05 (*) and p<0.01 (**) are indicated compared to sham treated animals examined at the same time point. Representative images of endothelial progenitor cells immunostained for markers are presented in the panels (B): single staining for CD31; double labeling for CD31 and CD34; staining for VEGFR and vWF. CEP-CFU: circulating endothelial progenitor cell-colony forming unit; PMNC: peripheral blood mononuclear cell; CD31; cluster of differentiation 31, CD34; cluster of differentiation 34, VEGFR: vascular endothelial growth factor receptor, vWF: von Willebrand factor. Scale bar: 50 µm.
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pone-0112397-g003: Effect of single dose cranial irradiation on circulating endothelial progenitor cell number.Single head irradiation with 0.1, 2 and 10 Gy doses was performed on 10-week-old adult mice. Circulating endothelial progenitor cell were isolated and cultured from peripheral blood mononuclear cells 1 day, 1, 4 and 26 weeks postirradiation (A). The number of endothelial progenitor cells is presented as colony forming unit/peripheral mononuclear cell ×105/ml blood. Values presented are means ± SD, n = 3–10 from 2–3 separate experiments. Statistical analysis: two-way ANOVA followed by Bonferroni post-test. Statistically significant differences p<0.05 (*) and p<0.01 (**) are indicated compared to sham treated animals examined at the same time point. Representative images of endothelial progenitor cells immunostained for markers are presented in the panels (B): single staining for CD31; double labeling for CD31 and CD34; staining for VEGFR and vWF. CEP-CFU: circulating endothelial progenitor cell-colony forming unit; PMNC: peripheral blood mononuclear cell; CD31; cluster of differentiation 31, CD34; cluster of differentiation 34, VEGFR: vascular endothelial growth factor receptor, vWF: von Willebrand factor. Scale bar: 50 µm.

Mentions: Blood-derived mouse CEPs were isolated 1 day, 1, 4 and 26 weeks after cranial X-ray exposure and cultured for 1–2 weeks. CEPs, derived from adherent PBMCs formed colonies surrounded by spindle-shaped cells, an early endothelial progenitor phenotype [44], [45], and gradually differentiated to a more endothelial-like morphology. Colonies of cultured CEPs stained positively for both CD34 and CD31 or vWF and VEGFR2 (Figure 3A, B) were counted. The number of CEPs colonies from cranial irradiated mice was significantly decreased 1 day after treatment and was still reduced at 4 weeks after 2 Gy exposure and gradually recovered by 26 weeks (Figure 3A). Cranial irradiation did not result in a significant drop in the number of PBMCs at day 1 (control: 15.53±2.43 105 cells/ml; 0.1 Gy: 9.81±1.88 105 cells/ml, p<0.071; 2 Gy: 9.99±1.41 105 cells/ml, p<0.065; One way ANOVA + Bonferroni test) or any other time points.


Low dose cranial irradiation-induced cerebrovascular damage is reversible in mice.

Sándor N, Walter FR, Bocsik A, Sántha P, Schilling-Tóth B, Léner V, Varga Z, Kahán Z, Deli MA, Sáfrány G, Hegyesi H - PLoS ONE (2014)

Effect of single dose cranial irradiation on circulating endothelial progenitor cell number.Single head irradiation with 0.1, 2 and 10 Gy doses was performed on 10-week-old adult mice. Circulating endothelial progenitor cell were isolated and cultured from peripheral blood mononuclear cells 1 day, 1, 4 and 26 weeks postirradiation (A). The number of endothelial progenitor cells is presented as colony forming unit/peripheral mononuclear cell ×105/ml blood. Values presented are means ± SD, n = 3–10 from 2–3 separate experiments. Statistical analysis: two-way ANOVA followed by Bonferroni post-test. Statistically significant differences p<0.05 (*) and p<0.01 (**) are indicated compared to sham treated animals examined at the same time point. Representative images of endothelial progenitor cells immunostained for markers are presented in the panels (B): single staining for CD31; double labeling for CD31 and CD34; staining for VEGFR and vWF. CEP-CFU: circulating endothelial progenitor cell-colony forming unit; PMNC: peripheral blood mononuclear cell; CD31; cluster of differentiation 31, CD34; cluster of differentiation 34, VEGFR: vascular endothelial growth factor receptor, vWF: von Willebrand factor. Scale bar: 50 µm.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4231057&req=5

pone-0112397-g003: Effect of single dose cranial irradiation on circulating endothelial progenitor cell number.Single head irradiation with 0.1, 2 and 10 Gy doses was performed on 10-week-old adult mice. Circulating endothelial progenitor cell were isolated and cultured from peripheral blood mononuclear cells 1 day, 1, 4 and 26 weeks postirradiation (A). The number of endothelial progenitor cells is presented as colony forming unit/peripheral mononuclear cell ×105/ml blood. Values presented are means ± SD, n = 3–10 from 2–3 separate experiments. Statistical analysis: two-way ANOVA followed by Bonferroni post-test. Statistically significant differences p<0.05 (*) and p<0.01 (**) are indicated compared to sham treated animals examined at the same time point. Representative images of endothelial progenitor cells immunostained for markers are presented in the panels (B): single staining for CD31; double labeling for CD31 and CD34; staining for VEGFR and vWF. CEP-CFU: circulating endothelial progenitor cell-colony forming unit; PMNC: peripheral blood mononuclear cell; CD31; cluster of differentiation 31, CD34; cluster of differentiation 34, VEGFR: vascular endothelial growth factor receptor, vWF: von Willebrand factor. Scale bar: 50 µm.
Mentions: Blood-derived mouse CEPs were isolated 1 day, 1, 4 and 26 weeks after cranial X-ray exposure and cultured for 1–2 weeks. CEPs, derived from adherent PBMCs formed colonies surrounded by spindle-shaped cells, an early endothelial progenitor phenotype [44], [45], and gradually differentiated to a more endothelial-like morphology. Colonies of cultured CEPs stained positively for both CD34 and CD31 or vWF and VEGFR2 (Figure 3A, B) were counted. The number of CEPs colonies from cranial irradiated mice was significantly decreased 1 day after treatment and was still reduced at 4 weeks after 2 Gy exposure and gradually recovered by 26 weeks (Figure 3A). Cranial irradiation did not result in a significant drop in the number of PBMCs at day 1 (control: 15.53±2.43 105 cells/ml; 0.1 Gy: 9.81±1.88 105 cells/ml, p<0.071; 2 Gy: 9.99±1.41 105 cells/ml, p<0.065; One way ANOVA + Bonferroni test) or any other time points.

Bottom Line: Blood-brain barrier permeability for Evans blue, body weight and number of peripheral mononuclear and circulating endothelial progenitor cells were evaluated 1, 4 and 26 weeks postirradiation.Endothelial senescence was determined by senescence associated β-galactosidase staining.Extravasation of Evans blue increased in cerebrum and cerebellum in adult mice 1 week and in infant mice 4 weeks postirradiation at all treatment doses.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Radiobiology and Biodosimetry, "Frédéric Joliot-Curie" National Research Institute for Radiobiology and Radiohygiene, Budapest, Hungary; Doctoral Schools of Pathological Sciences, Semmelweis University, Budapest, Hungary.

ABSTRACT

Background: High-dose radiation-induced blood-brain barrier breakdown contributes to acute radiation toxicity syndrome and delayed brain injury, but there are few data on the effects of low dose cranial irradiation. Our goal was to measure blood-brain barrier changes after low (0.1 Gy), moderate (2 Gy) and high (10 Gy) dose irradiation under in vivo and in vitro conditions.

Methodology: Cranial irradiation was performed on 10-day-old and 10-week-old mice. Blood-brain barrier permeability for Evans blue, body weight and number of peripheral mononuclear and circulating endothelial progenitor cells were evaluated 1, 4 and 26 weeks postirradiation. Barrier properties of primary mouse brain endothelial cells co-cultured with glial cells were determined by measurement of resistance and permeability for marker molecules and staining for interendothelial junctions. Endothelial senescence was determined by senescence associated β-galactosidase staining.

Principle findings: Extravasation of Evans blue increased in cerebrum and cerebellum in adult mice 1 week and in infant mice 4 weeks postirradiation at all treatment doses. Head irradiation with 10 Gy decreased body weight. The number of circulating endothelial progenitor cells in blood was decreased 1 day after irradiation with 0.1 and 2 Gy. Increase in the permeability of cultured brain endothelial monolayers for fluorescein and albumin was time- and radiation dose dependent and accompanied by changes in junctional immunostaining for claudin-5, ZO-1 and β-catenin. The number of cultured brain endothelial and glial cells decreased from third day of postirradiation and senescence in endothelial cells increased at 2 and 10 Gy.

Conclusion: Not only high but low and moderate doses of cranial irradiation increase permeability of cerebral vessels in mice, but this effect is reversible by 6 months. In-vitro experiments suggest that irradiation changes junctional morphology, decreases cell number and causes senescence in brain endothelial cells.

Show MeSH
Related in: MedlinePlus