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Anti-high mobility group box-1 (HMGB1) antibody inhibits hemorrhage-induced brain injury and improved neurological deficits in rats

View Article: PubMed Central - PubMed

ABSTRACT

As one of the most lethal stroke subtypes, intracerebral hemorrhage (ICH) is acknowledged as a serious clinical problem lacking effective treatment. Available evidence from preclinical and clinical studies suggests that inflammatory mechanisms are involved in the progression of ICH-induced secondary brain injury. High mobility group box-1 (HMGB1) is a ubiquitous and abundant nonhistone DNA-binding protein, and is also an important proinflammatory molecule once released into the extracellular space from the nuclei. Here, we show that treatment with neutralizing anti-HMGB1 mAb (1 mg/kg, i.v. twice) remarkably ameliorated ICH-injury induced by local injection of collagenase IV in the striatum of rats. Administration of anti-HMGB1 mAb inhibited the release of HMGB1 into the extracellular space in the peri-hematomal region, reduced serum HMGB1 levels and decreased brain edema by protecting blood-brain barrier integrity, in association with decreased activated microglia and the expression of inflammation-related factors at 24 h after ICH. Consequently, anti-HMGB1 mAb reduced the oxidative stress and improved the behavioral performance of rats. These results strongly indicate that HMGB1 plays a critical role in the development of ICH-induced secondary injury through the amplification of plural inflammatory responses. Intravenous injection of neutralizing anti-HMGB1 mAb has potential as a novel therapeutic strategy for ICH.

No MeSH data available.


Effects of anti-HMGB1 mAb on AQP4 expression in different brain regions at 24 h after ICH.(a) The brains were fixed at 24 h after ICH and the brain sections were immunostained with anti-AQP4. Typical pictures of the cerebral cortex, striatum and hippocampus are shown. Arrows indicate AQP4-positive structures. The scale bar represents 100 μm. (b) Quantification of AQP4-immunoreactive structures was performed in the cerebral cortex (F(2,9) = 15.649 p = 0.001), striatum (F(2,9) = 20.575 p < 0.001) and hippocampus (F(2,9) = 41.727, p < 0.001) in each group. Anti-HMGB1 mAb administration partially reversed the increase in the number of AQP4-immunoreactivities at 24 h after ICH. Results are shown for the sham group (Sham, n = 4), the control IgG-treated group (Con IgG, n = 4), and the anti-HMGB1 mAb-treated group (α-HMGB1, n = 4). Values represent the means ± SE. **p < 0.01 compared with the sham groups. #P < 0.05, ##P < 0.01 compared with the control IgG group.
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f4: Effects of anti-HMGB1 mAb on AQP4 expression in different brain regions at 24 h after ICH.(a) The brains were fixed at 24 h after ICH and the brain sections were immunostained with anti-AQP4. Typical pictures of the cerebral cortex, striatum and hippocampus are shown. Arrows indicate AQP4-positive structures. The scale bar represents 100 μm. (b) Quantification of AQP4-immunoreactive structures was performed in the cerebral cortex (F(2,9) = 15.649 p = 0.001), striatum (F(2,9) = 20.575 p < 0.001) and hippocampus (F(2,9) = 41.727, p < 0.001) in each group. Anti-HMGB1 mAb administration partially reversed the increase in the number of AQP4-immunoreactivities at 24 h after ICH. Results are shown for the sham group (Sham, n = 4), the control IgG-treated group (Con IgG, n = 4), and the anti-HMGB1 mAb-treated group (α-HMGB1, n = 4). Values represent the means ± SE. **p < 0.01 compared with the sham groups. #P < 0.05, ##P < 0.01 compared with the control IgG group.

Mentions: Since AQP4 expression has been suggested to be involved in increased BBB permeability, we next evaluated the effects of anti-HMGB1 mAb on AQP4 levels in ICH rats. We investigated AQP4 expression by immunohistochemistry 24 h after ICH, in the brain tissues of both control IgG- and anti-HMGB1 mAb-treated rats. As shown in Fig. 4, AQP4 immunoreactivities were observed in the cerebral cortex, striatum and hippocampus of control IgG-treated rats (white arrows in Fig. 4), whereas the immunoreactivity was much weaker in the sham group. The treatment with anti-HMGB1 led to a reduction in the immunoreactivity for AQP4 in ICH rats. We counted the number of AQP4- immunoreactive vessels (provided their lengths in the longitudinal direction were more than 10 μm) in the cerebral cortex, striatum and hippocampus. As shown in Fig. 4, the antibody-treated group showed a significantly reduced number of AQP4-positive vessels on the ipsilateral side in all these areas compared with the control IgG group.


Anti-high mobility group box-1 (HMGB1) antibody inhibits hemorrhage-induced brain injury and improved neurological deficits in rats
Effects of anti-HMGB1 mAb on AQP4 expression in different brain regions at 24 h after ICH.(a) The brains were fixed at 24 h after ICH and the brain sections were immunostained with anti-AQP4. Typical pictures of the cerebral cortex, striatum and hippocampus are shown. Arrows indicate AQP4-positive structures. The scale bar represents 100 μm. (b) Quantification of AQP4-immunoreactive structures was performed in the cerebral cortex (F(2,9) = 15.649 p = 0.001), striatum (F(2,9) = 20.575 p < 0.001) and hippocampus (F(2,9) = 41.727, p < 0.001) in each group. Anti-HMGB1 mAb administration partially reversed the increase in the number of AQP4-immunoreactivities at 24 h after ICH. Results are shown for the sham group (Sham, n = 4), the control IgG-treated group (Con IgG, n = 4), and the anti-HMGB1 mAb-treated group (α-HMGB1, n = 4). Values represent the means ± SE. **p < 0.01 compared with the sham groups. #P < 0.05, ##P < 0.01 compared with the control IgG group.
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f4: Effects of anti-HMGB1 mAb on AQP4 expression in different brain regions at 24 h after ICH.(a) The brains were fixed at 24 h after ICH and the brain sections were immunostained with anti-AQP4. Typical pictures of the cerebral cortex, striatum and hippocampus are shown. Arrows indicate AQP4-positive structures. The scale bar represents 100 μm. (b) Quantification of AQP4-immunoreactive structures was performed in the cerebral cortex (F(2,9) = 15.649 p = 0.001), striatum (F(2,9) = 20.575 p < 0.001) and hippocampus (F(2,9) = 41.727, p < 0.001) in each group. Anti-HMGB1 mAb administration partially reversed the increase in the number of AQP4-immunoreactivities at 24 h after ICH. Results are shown for the sham group (Sham, n = 4), the control IgG-treated group (Con IgG, n = 4), and the anti-HMGB1 mAb-treated group (α-HMGB1, n = 4). Values represent the means ± SE. **p < 0.01 compared with the sham groups. #P < 0.05, ##P < 0.01 compared with the control IgG group.
Mentions: Since AQP4 expression has been suggested to be involved in increased BBB permeability, we next evaluated the effects of anti-HMGB1 mAb on AQP4 levels in ICH rats. We investigated AQP4 expression by immunohistochemistry 24 h after ICH, in the brain tissues of both control IgG- and anti-HMGB1 mAb-treated rats. As shown in Fig. 4, AQP4 immunoreactivities were observed in the cerebral cortex, striatum and hippocampus of control IgG-treated rats (white arrows in Fig. 4), whereas the immunoreactivity was much weaker in the sham group. The treatment with anti-HMGB1 led to a reduction in the immunoreactivity for AQP4 in ICH rats. We counted the number of AQP4- immunoreactive vessels (provided their lengths in the longitudinal direction were more than 10 μm) in the cerebral cortex, striatum and hippocampus. As shown in Fig. 4, the antibody-treated group showed a significantly reduced number of AQP4-positive vessels on the ipsilateral side in all these areas compared with the control IgG group.

View Article: PubMed Central - PubMed

ABSTRACT

As one of the most lethal stroke subtypes, intracerebral hemorrhage (ICH) is acknowledged as a serious clinical problem lacking effective treatment. Available evidence from preclinical and clinical studies suggests that inflammatory mechanisms are involved in the progression of ICH-induced secondary brain injury. High mobility group box-1 (HMGB1) is a ubiquitous and abundant nonhistone DNA-binding protein, and is also an important proinflammatory molecule once released into the extracellular space from the nuclei. Here, we show that treatment with neutralizing anti-HMGB1 mAb (1&thinsp;mg/kg, i.v. twice) remarkably ameliorated ICH-injury induced by local injection of collagenase IV in the striatum of rats. Administration of anti-HMGB1 mAb inhibited the release of HMGB1 into the extracellular space in the peri-hematomal region, reduced serum HMGB1 levels and decreased brain edema by protecting blood-brain barrier integrity, in association with decreased activated microglia and the expression of inflammation-related factors at 24&thinsp;h after ICH. Consequently, anti-HMGB1 mAb reduced the oxidative stress and improved the behavioral performance of rats. These results strongly indicate that HMGB1 plays a critical role in the development of ICH-induced secondary injury through the amplification of plural inflammatory responses. Intravenous injection of neutralizing anti-HMGB1 mAb has potential as a novel therapeutic strategy for ICH.

No MeSH data available.