title: NADH fluorescence imaging and the histological impact of cortical spreading depolarization during the acute phase of subarachnoid hemorrhage in rats.
abstract: OBJECTIVE Although cortical spreading depolarization (CSD) has been observed during the early phase of subarachnoid hemorrhage (SAH) in clinical settings, the pathogenicity of CSD is unclear. The aim of this study is to elucidate the effects of loss of membrane potential on neuronal damage during the acute phase of SAH. METHODS Twenty-four rats were subjected to SAH by the perforation method. The propagation of depolarization in the brain cortex was examined by using electrodes to monitor 2 direct-current (DC) potentials and obtaining NADH (reduced nicotinamide adenine dinucleotide) fluorescence images while exposing the parietal-temporal cortex to ultraviolet light. Cerebral blood flow (CBF) was monitored in the vicinity of the lateral electrode. Twenty-four hours after onset of SAH, histological damage was evaluated at the DC potential recording sites. RESULTS Changes in DC potentials (n = 48 in total) were sorted into 3 types according to the appearance of ischemic depolarization in the entire hemisphere following induction of SAH. In Type 1 changes (n = 21), ischemic depolarization was not observed during a 1-hour observation period. In Type 2 changes (n = 13), the DC potential demonstrated ischemic depolarization on initiation of SAH and recovered 80% from the maximal DC deflection during a 1-hour observation period (33.3 ± 15.8 minutes). In Type 3 changes (n = 14), the DC potential displayed ischemic depolarization and did not recover during a 1-hour observation period. Histological evaluations at DC potential recording sites showed intact tissue at all sites in the Type 1 group, whereas in the Type 2 and Type 3 groups neuronal damage of varying severity was observed depending on the duration of ischemic depolarization. The duration of depolarization that causes injury to 50% of neurons (P50) was estimated to be 22.4 minutes (95% confidence intervals 17.0-30.3 minutes). CSD was observed in 3 rats at 6 sites in the Type 1 group 5.1 ± 2.2 minutes after initiation of SAH. On NADH fluorescence images CSD was initially observed in the anterior cortex; it propagated through the entire hemisphere in the direction of the occipital cortex at a rate of 3 mm/minute, with repolarization in 2.3 ± 1.2 minutes. DC potential recording sites that had undergone CSD were found to have intact tissue 24 hours later. Compared with depolarization that caused 50% neuronal damage, the duration of CSD was too short to cause histological damage. CONCLUSIONS CSD was successfully visualized using NADH fluorescence. It propagated from the anterior to the posterior cortex along with an increase in CBF. The duration of depolarization in CSD (2.3 ± 1.2 minutes) was far shorter than that causing 50% neuronal damage (22.4 minutes) and was not associated with histological damage in the current experimental setting.
authors.affiliation: 1Department of Neurological Surgery and.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: 1Department of Neurological Surgery and.
authors.forename: Tomohito
authors.initials: T
authors.lastname: Hishikawa
authors.affiliation: 1Department of Neurological Surgery and.
authors.forename: Shingo
authors.initials: S
authors.lastname: Nishihiro
authors.affiliation: 1Department of Neurological Surgery and.
authors.forename: Yukei
authors.initials: Y
authors.lastname: Shinji
authors.affiliation: 1Department of Neurological Surgery and.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takasugi
authors.affiliation: 1Department of Neurological Surgery and.
authors.forename: Jun
authors.initials: J
authors.lastname: Haruma
authors.affiliation: 1Department of Neurological Surgery and.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Hiramatsu
authors.affiliation: 2Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kawase
authors.affiliation: 2Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Sato
authors.affiliation: 2Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Mizoue
authors.affiliation: 2Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Takeda
authors.affiliation: 1Department of Neurological Surgery and.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugiu
authors.affiliation: 2Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morimatsu
authors.affiliation: 1Department of Neurological Surgery and.
authors.forename: Isao
authors.initials: I
authors.lastname: Date
mesh_terms: D000208:Acute Disease; D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D013181:Cortical Spreading Depression; D004195:Disease Models, Animal; D005456:Fluorescent Dyes; D007427:Intracranial Pressure; D008297:Male; D009243:NAD; D017207:Rats, Sprague-Dawley; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging* / Q000503:physiopathology
chemical_list: D005456:Fluorescent Dyes; D009243:NAD
keywords: ADC = apparent diffusion coefficient; CBF = cerebral blood flow; CCD = charge-coupled device; CSD = cortical spreading depolarization; DC = direct current; ICP = intracranial pressure; NAD+ = oxidized nicotinamide adenine dinucleotide; NADH = reduced nicotinamide adenine dinucleotide; SAH = subarachnoid hemorrhage; histological evaluation; spreading depolarization; subarachnoid hemorrhage; vascular disorders