Dynamic changes of inflammatory markers in brain after hemorrhagic stroke in humans: a postmortem study

Abstract

This histopathologic case-control study was designed to characterize the dynamic changes in protein expression of nuclear factor-kappa B (NF-kappaB)/p65 subunit, macrophage inflammatory protein-2 (MIP-2), and matrix metalloproteinase-9 (MMP-9) in postmortem brains of patients with and without intracerebral hemorrhage (ICH). Thirty-six human brains from patients with ICH and six control brains were included in this study. We found that expression levels of NF-kappaB/p65, MIP-2, and MMP-9 were each upregulated on the injured side of the hippocampus at times ranging from 2h to 5days post-ICH. Interestingly, the expression of all three markers was also upregulated on the uninjured side of the hippocampus and in the cerebellum, although to a lesser extent. These data suggest that inflammation occurs early and persists for several days after ICH in humans and could be involved in the progression of ICH-induced secondary brain damage.

Fig. 1

Hematoxylin and eosin staining in the CA1 region of hippocampus. (A) Control group: non-ischemic pyramidal neurons had normal morphology; (B) 2 hr after ICH: limited neurons were pyknotic; (C) 24 hr after ICH: some neurons were triangular and pyknotic. Scale bar = 50 µm.

Fig. 2

Effect of ICH on immunoreactivity of NF-κB/p65, MIP-2, and MMP-9 in the cerebellum. (A) Protein expression of NF-κB/p65 subunit in cerebellum of the control group. The immunopositive cells showed brown staining. (B) After ICH, NF-κB/p65 immunoreactivity increased and appeared in cell bodies of Purkinje cells in the cerebellum. (C) NF-κB/p65 immunoreactivity increased in some white matter neurons in the cerebellum after ICH. (D) Immunoreactivity of MIP-2 in cerebellum of the control group. (E) MIP-2 immunoreactivity was elevated in cerebellum at 2 hr after ICH. (F) MIP-2 immunoreactivity was elevated in cell bodies of Purkinje cells at 24 hr after ICH. (G) Immunoreactivity of MMP-9 in cerebellum of the control group. (H) Immunoreactivity of MMP-9 was elevated in cell bodies of Purkinje cells in the cerebellum at 2 hr after ICH. (I) Immunoreactivity of MMP-9 was elevated in the cerebellum at 24 hr after ICH. Scale bar = 50 µm.

Fig. 3

Effect of ICH on immunoreactivity of NF-κB/p65, MIP-2, and MMP-9 in the hippocampus. (A) Protein expression of NF-κB/p65 subunit in hippocampus of the control group. NF-κB/p65 immunoreactivity was elevated on the injured side of the hippocampus at 2 hr (B) and 24 hr (C) after ICH. (D) MIP-2 immunoreactivity in hippocampus of the control group. MIP-2 immunoreactivity was elevated on the injured side of the hippocampus 2 hr (E) and 24 hr (F) after ICH. (G) Immunoreactivity of MMP-9 in hippocampus of the control group. Immunoreactivity of MMP-9 was elevated on the injured side of the hippocampus 2 hr (H) and 24 hr (I) after ICH. Scale bar = 50 µm.