Single-Cell Resolution Mapping of Neuronal Damage in Acute Focal Cerebral Ischemia Using Thallium Autometallography

Abstract

Neuronal damage shortly after onset or after brief episodes of cerebral ischemia has remained difficult to assess with clinical and preclinical imaging techniques as well as with microscopical methods. We here show, in rodent models of middle cerebral artery occlusion (MCAO), that neuronal damage in acute focal cerebral ischemia can be mapped with single-cell resolution using thallium autometallography (TlAMG), a histochemical technique for the detection of the K+-probe thallium (Tl+) in the brain. We intravenously injected rats and mice with thallium diethyldithiocarbamate (TlDDC), a lipophilic chelate complex that releases Tl+ after crossing the blood–brain barrier. We found, within the territories of the affected arteries, areas of markedly reduced neuronal Tl+ uptake in all animals at all time points studied ranging from 15 minutes to 24 hours after MCAO. In large lesions at early time points, areas with neuronal and astrocytic Tl+ uptake below thresholds of detection were surrounded by putative penumbral zones with preserved but diminished Tl+ uptake. At 24 hours, the areas of reduced Tl+uptake matched with areas delineated by established markers of neuronal damage. The results suggest the use of 201TlDDC for preclinical and clinical single-photon emission computed tomography (SPECT) imaging of hyperacute alterations in brain K+ metabolism and prediction of tissue viability in cerebral ischemia.

Activation of the mouse primary visual cortex by medial prefrontal subregion stimulation is not mediated by cholinergic basalo-cortical projections

“…Tl accumulates in cells and neurites during neuronal activation (Figure 2 ) through potassium channels. TlAMG Tl is then fixed by the perfusion of a sodium sulfide solution and is developed with silver for visualization under a microscope, as extensively described (Goldschmidt et al, 2004 ; Stöber et al, 2014 ). The use of TlAMG to visualize neuronal activation is similar to the 2-deoxyglucose method from Sokoloff (Goldschmidt et al, 2004 ), but with a subcellular resolution.…”

“…Gray-scaled microphotographs were captured with a 40X Leica Fluotar objective quantification and a Leica DC500 camera. Neuron count and optical density quantification were performed using the mean gray values evaluated by ImageJ (Stöber et al, 2014 ). Three slices from each animal at −2.54, −2.92 and −3.40 mm from Bregma for V1 and at 0.74, 0.38 and 0.14 mm from Bregma for HDB and substantia innominata were selected for neuron count and/or mean gray values analysis in layers II/III, IV and V of V1.…”

“…In the present study, the anatomo-functional interaction between the mPFC, HDB and V1 was examined in the mouse. Electrical stimulation of the two major mPFC subregions, IL/PrL and the AC, was performed, and the resulting neuronal activation was examined in V1 and the HDB by c-Fos immunocytochemistry and thallium (Tl) autometallography (TlAMG; Danscher, 1981 ; Goldschmidt et al, 2004 ; Stöber et al, 2014 ). The two complimentary techniques assess different aspects of neuronal activity.…”

Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins

“…The mice (male, 8–20 weeks) were anesthetized with isoflurane (Baxter, Unterschleissheim, Germany; induction 1.5–2%, maintenance 1–1.5% in 70% N 2 O/30% O 2 ), and the left common and external carotid arteries were isolated and ligated. 30 A microvascular clip was placed on the internal carotid artery. For MCAO, a silicon rubber-coated monofilament (size 7–0; Doccol, Redlands, USA) was introduced through a small incision into the common carotid artery and advanced to 9 mm distal from carotid bifurcation; 30 or 60 min after the onset of the occlusion, the filament was removed under isoflurane anesthesia for complete reperfusion of the MCA for 3 h or 48 h. The internal CA was then ligated.…”

Application of Thallium Autometallography for Observation of Changes in Excitability of Rodent Brain following Acute Carbon Monoxide Intoxication

“…TI + 은 1가 양이 온으로써 세포외에서 세포내로 이동할 수 있는데, 이 때 K + 와 유사한 이동방식을 취한다. 즉, Na + -K + ATPase (pump)의 작동을 통하여 TI + 은 K + 와 경쟁적으로 세포 밖 에서 세포 안으로 이동할 수 있다 13,14) . 따라서 신경세포의 전기적 활동성 증가로 인한 Na + -K + ATPase 활성이 증가 하면 TI + 의 세포 내 유입이 증가하여 세포 내에 농도가 증가 된다.…”