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Neurological deficits caused by tissue hypoxia in neuroinflammatory disease
Author(s) -
Davies Andrew L.,
Desai Roshni A.,
Bloomfield Peter S.,
McIntosh Peter R.,
Chapple Katie J.,
Linington Christopher,
Fairless Richard,
Diem Ricarda,
Kasti Marianne,
Murphy Michael P.,
Smith Kenneth J.
Publication year - 2013
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.24006
Subject(s) - hypoxia (environmental) , multiple sclerosis , myelin oligodendrocyte glycoprotein , spinal cord , experimental autoimmune encephalomyelitis , central nervous system , medicine , neuroinflammation , pathology , spinal cord injury , white matter , nitric oxide synthase , nitric oxide , anesthesia , endocrinology , immunology , biology , neuroscience , magnetic resonance imaging , chemistry , oxygen , disease , organic chemistry , radiology
Objective To explore the presence and consequences of tissue hypoxia in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Methods EAE was induced in Dark Agouti rats by immunization with recombinant myelin oligodendrocyte glycoprotein and adjuvant. Tissue hypoxia was assessed in vivo using 2 independent methods: an immunohistochemical probe administered intravenously, and insertion of a physical, oxygen‐sensitive probe into the spinal cord. Indirect markers of tissue hypoxia (eg, expression of hypoxia‐inducible factor‐1α [HIF‐1α], vessel diameter, and number of vessels) were also assessed. The effects of brief (1 hour) and continued (7 days) normobaric oxygen treatment on function were evaluated in conjunction with other treatments, namely administration of a mitochondrially targeted antioxidant (MitoQ) and inhibition of inducible nitric oxide synthase (1400W). Results Observed neurological deficits were quantitatively, temporally, and spatially correlated with spinal white and gray matter hypoxia. The tissue expression of HIF‐1α also correlated with loss of function. Spinal microvessels became enlarged during the hypoxic period, and their number increased at relapse. Notably, oxygen administration significantly restored function within 1 hour, with improvement persisting at least 1 week with continuous oxygen treatment. MitoQ and 1400W also caused a small but significant improvement. Interpretation We present chemical, physical, immunohistochemical, and therapeutic evidence that functional deficits caused by neuroinflammation can arise from tissue hypoxia, consistent with an energy crisis in inflamed central nervous system tissue. The neurological deficit was closely correlated with spinal white and gray matter hypoxia. This realization may indicate new avenues for therapy of neuroinflammatory diseases such as MS. Ann Neurol 2013;74:815–825