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Assessing the axonal translocation of CeO2 and SiO2 nanoparticles in the sciatic nerve fibers of the frog: an ex vivo electrophysiological study.

Kastrinaki G, Samsouris C, Kosmidis EK, Papaioannou E, Konstandopoulos AG, Theophilidis G - Int J Nanomedicine (2015)

Bottom Line: For the CeO2, we also demonstrated that the translocation depends on both axonal integrity and electrical activity.The speed of translocation for the two species was estimated in the range of 0.45-0.58 mm/h, close to slow axonal transportation rate.Transmission electron microscopy provided direct evidence for the presence of SiO2 in the treated nerves.

View Article: PubMed Central - PubMed

Affiliation: Aerosol and Particle Technology Laboratory (APTL), CERTH/CPERI, Thessaloniki, Greece.

ABSTRACT
The axonal translocation of two commonly used nanoparticles in medicine, namely CeO2 and SiO2, is investigated. The study was conducted on frog sciatic nerve fibers in an ex vivo preparation. Nanoparticles were applied at the proximal end of the excised nerve. A nerve stimulation protocol was followed for over 35 hours. Nerve vitality curve comparison between control and exposed nerves showed that CeO2 has no neurotoxic effect at the concentrations tested. After exposure, specimens were fixed and then screen scanned every 1 mm along their length for nanoparticle presence by means of Fourier transform infrared microscopy. We demonstrated that both nanoparticles translocate within the nerve by formation of narrow bands in the Fourier transform infrared spectrum. For the CeO2, we also demonstrated that the translocation depends on both axonal integrity and electrical activity. The speed of translocation for the two species was estimated in the range of 0.45-0.58 mm/h, close to slow axonal transportation rate. Transmission electron microscopy provided direct evidence for the presence of SiO2 in the treated nerves.

No MeSH data available.


Related in: MedlinePlus

Experimental setup and electrophysiology.Notes: (A) Recording bath scheme. (B) Schematic representation of sciatic nerve’s proximal, middle, and distal regions. (C) Indicative evoked CAPs from whole nerve recordings. (D) Nerve vitality curve for CeO2.Abbreviations: C, glass cover; CAP, compound action potential; n, perfusion chamber; NPs, nanoparticles; part, partition; R, recording chamber; S, stimulating chamber; Xanth, Xantopren; h, hours.
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f1-ijn-10-7089: Experimental setup and electrophysiology.Notes: (A) Recording bath scheme. (B) Schematic representation of sciatic nerve’s proximal, middle, and distal regions. (C) Indicative evoked CAPs from whole nerve recordings. (D) Nerve vitality curve for CeO2.Abbreviations: C, glass cover; CAP, compound action potential; n, perfusion chamber; NPs, nanoparticles; part, partition; R, recording chamber; S, stimulating chamber; Xanth, Xantopren; h, hours.

Mentions: Frogs (Rana ridibunda) of either sex and of the same age (ranging from 12 to 15 months), weighing 40–60 g, were used. The frogs were euthanatized (decapitated and pithed), and the sciatic nerves were dissected from the spinal cord to the knee, immersed in standard physiological saline solution, and cleaned under a dissection microscope. All experimental procedures were conducted in accordance with the protocols outlined by the Aristotle University of Thessaloniki, Greece, regarding the recommended standard practices for Biological Investigations. When required, the epineural sheath was removed. The composition of the saline was (in mmol/L): NaCl 135, KCl 4.7, CaCl2 2.4, MgCl2 1.1, NaHCO3 1.0, HEPES 10, glucose 11 (pH 7.4). The nerve was mounted across a three-chambered recording bath, made of Plexiglas, a diagram of which is shown in Figure 1A. The recording bath has been used in a variety of ex vivo neurotoxicological studies and it is fully described elsewhere,34–36 but a short description will be given below in order to clarify the protocol for the exposure of the nerve to NPs. The recording bath consists of three chambers: 1) the stimulating chamber (S in Figure 1A) where the proximal cut end of the nerve (Figure 1B) and the active stimulating electrode were placed. The stimulating electrode was connected to a constant voltage stimulator (Digitimer, DS9A; Digitimer Ltd, Welwyn Garden City, UK); 2) the perfusion chamber (n in Figure 1A), where the middle of the nerve was immersed and the grounds of the recording and stimulating electrodes were placed; and 3) the recording chamber (R in Figure 1A), where the distal end of the nerve and the active electrode of an AC (alternating current) differentiate amplifier (Neurolog, NL822; Digitimer Ltd) were placed. Gold electrodes of 24 carat were used. The dimensions of each chamber were 22×22×10 mm (length, width, depth), allowing a solution volume of 10 mL. The three chambers were next to each other, separated by two partitions of 2 mm width (part in Figure 1A).


Assessing the axonal translocation of CeO2 and SiO2 nanoparticles in the sciatic nerve fibers of the frog: an ex vivo electrophysiological study.

Kastrinaki G, Samsouris C, Kosmidis EK, Papaioannou E, Konstandopoulos AG, Theophilidis G - Int J Nanomedicine (2015)

Experimental setup and electrophysiology.Notes: (A) Recording bath scheme. (B) Schematic representation of sciatic nerve’s proximal, middle, and distal regions. (C) Indicative evoked CAPs from whole nerve recordings. (D) Nerve vitality curve for CeO2.Abbreviations: C, glass cover; CAP, compound action potential; n, perfusion chamber; NPs, nanoparticles; part, partition; R, recording chamber; S, stimulating chamber; Xanth, Xantopren; h, hours.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664516&req=5

f1-ijn-10-7089: Experimental setup and electrophysiology.Notes: (A) Recording bath scheme. (B) Schematic representation of sciatic nerve’s proximal, middle, and distal regions. (C) Indicative evoked CAPs from whole nerve recordings. (D) Nerve vitality curve for CeO2.Abbreviations: C, glass cover; CAP, compound action potential; n, perfusion chamber; NPs, nanoparticles; part, partition; R, recording chamber; S, stimulating chamber; Xanth, Xantopren; h, hours.
Mentions: Frogs (Rana ridibunda) of either sex and of the same age (ranging from 12 to 15 months), weighing 40–60 g, were used. The frogs were euthanatized (decapitated and pithed), and the sciatic nerves were dissected from the spinal cord to the knee, immersed in standard physiological saline solution, and cleaned under a dissection microscope. All experimental procedures were conducted in accordance with the protocols outlined by the Aristotle University of Thessaloniki, Greece, regarding the recommended standard practices for Biological Investigations. When required, the epineural sheath was removed. The composition of the saline was (in mmol/L): NaCl 135, KCl 4.7, CaCl2 2.4, MgCl2 1.1, NaHCO3 1.0, HEPES 10, glucose 11 (pH 7.4). The nerve was mounted across a three-chambered recording bath, made of Plexiglas, a diagram of which is shown in Figure 1A. The recording bath has been used in a variety of ex vivo neurotoxicological studies and it is fully described elsewhere,34–36 but a short description will be given below in order to clarify the protocol for the exposure of the nerve to NPs. The recording bath consists of three chambers: 1) the stimulating chamber (S in Figure 1A) where the proximal cut end of the nerve (Figure 1B) and the active stimulating electrode were placed. The stimulating electrode was connected to a constant voltage stimulator (Digitimer, DS9A; Digitimer Ltd, Welwyn Garden City, UK); 2) the perfusion chamber (n in Figure 1A), where the middle of the nerve was immersed and the grounds of the recording and stimulating electrodes were placed; and 3) the recording chamber (R in Figure 1A), where the distal end of the nerve and the active electrode of an AC (alternating current) differentiate amplifier (Neurolog, NL822; Digitimer Ltd) were placed. Gold electrodes of 24 carat were used. The dimensions of each chamber were 22×22×10 mm (length, width, depth), allowing a solution volume of 10 mL. The three chambers were next to each other, separated by two partitions of 2 mm width (part in Figure 1A).

Bottom Line: For the CeO2, we also demonstrated that the translocation depends on both axonal integrity and electrical activity.The speed of translocation for the two species was estimated in the range of 0.45-0.58 mm/h, close to slow axonal transportation rate.Transmission electron microscopy provided direct evidence for the presence of SiO2 in the treated nerves.

View Article: PubMed Central - PubMed

Affiliation: Aerosol and Particle Technology Laboratory (APTL), CERTH/CPERI, Thessaloniki, Greece.

ABSTRACT
The axonal translocation of two commonly used nanoparticles in medicine, namely CeO2 and SiO2, is investigated. The study was conducted on frog sciatic nerve fibers in an ex vivo preparation. Nanoparticles were applied at the proximal end of the excised nerve. A nerve stimulation protocol was followed for over 35 hours. Nerve vitality curve comparison between control and exposed nerves showed that CeO2 has no neurotoxic effect at the concentrations tested. After exposure, specimens were fixed and then screen scanned every 1 mm along their length for nanoparticle presence by means of Fourier transform infrared microscopy. We demonstrated that both nanoparticles translocate within the nerve by formation of narrow bands in the Fourier transform infrared spectrum. For the CeO2, we also demonstrated that the translocation depends on both axonal integrity and electrical activity. The speed of translocation for the two species was estimated in the range of 0.45-0.58 mm/h, close to slow axonal transportation rate. Transmission electron microscopy provided direct evidence for the presence of SiO2 in the treated nerves.

No MeSH data available.


Related in: MedlinePlus