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Propidium iodide in vivo: An early marker of neuronal damage in rat hippocampus

University of Southampton, Southampton, England, United Kingdom
Neuroscience Letters (Impact Factor: 2.06). 11/1994; 180(2):223-6. DOI: 10.1016/0304-3940(94)90525-8
Source: PubMed

ABSTRACT We have investigated the use of the fluorescent exclusion dye propidium iodide as a marker for acutely degenerating cells in vivo, and report here that combined injection of kainic acid and propidium iodide into the lateral cerebral ventricle results in labelling of CA3 pyramidal cells 1 and 6 h after injection. Alternate sections stained with thionin at these early times revealed little evidence of histologically detectable cell damage.

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    • "Hippocampal changes induced by KA in vivo are influenced by way of its administration. The intracerebroventricular (icv) injection of sub microgram amounts of KA in the rat produced more restricted damage to hippocampal neurons as compared to systemic administration (Nadler et al., 1980, Wilde et al., 1994, Lee et al., 2002). Both neurochemical and morphological changes developed swiftly in the CA3 region while other hippocampal regions remained spared. "
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    ABSTRACT: Intraventricular (i.c.v.) kainic acid (KA) causes an acute excitotoxic lesion to the CA3 region of rodent hippocampus. Recent evidence implicated c-fos gene in regulating neuron survival and death following an excitotoxic insult. In this study we attempted to prevent KA-induced damage in CA3 neurons with NMDA preconditioning, which produced a marked expression of c-fos in the hippocampus. NMDA (0.6-6 microg, i.c.v.) was injected to anesthetized rats alone or 1 h before KA (0.15 microg, i.c.v.). Following KA injection, vibratome sections were processed for immunohistochemistry/electron microscopy. c-Fos and Nissl staining were used to estimate the extent of neuronal excitation and damage, respectively. Quantitative evaluation of c-Fos-labeled cells showed significantly less c-Fos in CA3a than in neighboring CA3b and CA2 from 1 to 4 h after KA alone. Attenuation of expressed c-Fos in CA3a was accompanied by damage of neurons with more apoptotic than necrotic signs. NMDA preconditioning elevated CA3a c-Fos expression and at 1 and 2 h exceeded markedly that after KA alone. However, at 4 h after KA, NMDA-preconditioned c-Fos induction in CA3a diminished to the same level as that seen after KA alone. The onset of neuronal degeneration was delayed in similar way. While NMDA-induced c-Fos expression in CA3a could be blocked by MK-801 completely, MK-801 and CNQX were both without significant effect on KA-induced c-Fos expression and neuronal damage. In conclusion, inhibition of c-Fos expression and onset of neuronal damage in CA3a following icv KA injection might be transiently delayed by i.c.v. NMDA preconditioning.
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    • "About 50 eggs were used in vasoconstriction experiments. Tissue damage in the vicinity of the pipette was assessed immediately after the treatment using a standard cell membrane permeability assay based on propidium iodide (PI) fluorescent dye (Sigma–Aldrich, St. Louis, MO) [Belloc et al., 1994; Wilde et al., 1994; Bevensee et al., 1995]. PI is normally a cell-impermeant molecule, and undergoes a 40-fold enhancement of fluorescence upon binding to nucleic acids. "
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    • "The output current was determined by measuring the voltage drop across a resistor connected between the return electrode in the medium and the ground electrode of the pulse generator, as shown in Fig. 1. Tissue damage was assessed using a standard membrane permeability assay based on propidium iodide (PI) fluorescent dye (Sigma-Aldrich, St. Louis, MO) [21]–[23]. PI is a normally cell-impermeant molecule, which undergoes a 40-fold enhancement of fluorescence upon binding to nucleic acids. PI fluorescence of the cell indicates abnormal permeability of the cell membrane or even disintegration of the membrane and nucleus [24], [25]. "
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