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Compact Laser Doppler Flowmeter (LDF) Fundus Camera for the Assessment of Retinal Blood Perfusion in Small Animals.

Mentek M, Truffer F, Chiquet C, Godin-Ribuot D, Amoos S, Loeuillet C, Bernabei M, Geiser M - PLoS ONE (2015)

Bottom Line: Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF).Inter-day reproducibility was good (0.79 and 0.7, respectively).Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.

View Article: PubMed Central - PubMed

Affiliation: HP2 laboratory, Grenoble Alpes University, 38000, Grenoble, France; INSERM U1042 laboratory, 38000, Grenoble, France.

ABSTRACT

Purpose: Noninvasive techniques for ocular blood perfusion assessment are of crucial importance for exploring microvascular alterations related to systemic and ocular diseases. However, few techniques adapted to rodents are available and most are invasive or not specifically focused on the optic nerve head (ONH), choroid or retinal circulation. Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF).

Methods: A confocal miniature flowmeter was fixed to a specially designed 3D rotating mechanical arm and adjusted on a rodent stereotaxic table in order to accurately point the laser beam at the retinal region of interest. The linearity of the LDF measurements was assessed using a rotating Teflon wheel and a flow of microspheres in a glass capillary. In vivo reproducibility was assessed in Wistar rats with repeated measurements (inter-session and inter-day) of retinal arteries and ONH blood velocity in six and ten rats, respectively. These parameters were also recorded during an acute intraocular pressure increase to 150 mmHg and after heart arrest (n = 5 rats).

Results: The perfusion measurements showed perfect linearity between LDF velocity and Teflon wheel or microsphere speed. Intraclass correlation coefficients for retinal arteries and ONH velocity (0.82 and 0.86, respectively) indicated strong inter-session repeatability and stability. Inter-day reproducibility was good (0.79 and 0.7, respectively). Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.

Conclusion: We have demonstrated that, while not adapted for ONH blood perfusion assessment, this device allows pertinent, stable and repeatable measurements of retinal blood perfusion in rats.

No MeSH data available.


Related in: MedlinePlus

Stereotaxic table view.The LDF unit is held in three dimensions by a rotating arm. Accurate movements are enabled by five micrometric screws. x and y permit movements of the table in the horizontal plane. z permits vertical movements of the rat head. Θ and γ permit modification of the angulation of the emitted light into the eye.
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pone.0134378.g002: Stereotaxic table view.The LDF unit is held in three dimensions by a rotating arm. Accurate movements are enabled by five micrometric screws. x and y permit movements of the table in the horizontal plane. z permits vertical movements of the rat head. Θ and γ permit modification of the angulation of the emitted light into the eye.

Mentions: The rat is fixed on a modified stereotaxic instrument (Kopf instruments, Tujunga, CA, USA). The optical device is mounted on a dedicated positioning holder (Fig 2), which allows an adjustment in the (x, y, z) directions to bring the pupil of the optical device into the pupil of the eye, with 10-μm precision, without exerting any pressure on the eye. Then a rotation (θ, γ) around the center of the animal’s pupil brings the probing beam to the desired retinal location.


Compact Laser Doppler Flowmeter (LDF) Fundus Camera for the Assessment of Retinal Blood Perfusion in Small Animals.

Mentek M, Truffer F, Chiquet C, Godin-Ribuot D, Amoos S, Loeuillet C, Bernabei M, Geiser M - PLoS ONE (2015)

Stereotaxic table view.The LDF unit is held in three dimensions by a rotating arm. Accurate movements are enabled by five micrometric screws. x and y permit movements of the table in the horizontal plane. z permits vertical movements of the rat head. Θ and γ permit modification of the angulation of the emitted light into the eye.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4520556&req=5

pone.0134378.g002: Stereotaxic table view.The LDF unit is held in three dimensions by a rotating arm. Accurate movements are enabled by five micrometric screws. x and y permit movements of the table in the horizontal plane. z permits vertical movements of the rat head. Θ and γ permit modification of the angulation of the emitted light into the eye.
Mentions: The rat is fixed on a modified stereotaxic instrument (Kopf instruments, Tujunga, CA, USA). The optical device is mounted on a dedicated positioning holder (Fig 2), which allows an adjustment in the (x, y, z) directions to bring the pupil of the optical device into the pupil of the eye, with 10-μm precision, without exerting any pressure on the eye. Then a rotation (θ, γ) around the center of the animal’s pupil brings the probing beam to the desired retinal location.

Bottom Line: Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF).Inter-day reproducibility was good (0.79 and 0.7, respectively).Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.

View Article: PubMed Central - PubMed

Affiliation: HP2 laboratory, Grenoble Alpes University, 38000, Grenoble, France; INSERM U1042 laboratory, 38000, Grenoble, France.

ABSTRACT

Purpose: Noninvasive techniques for ocular blood perfusion assessment are of crucial importance for exploring microvascular alterations related to systemic and ocular diseases. However, few techniques adapted to rodents are available and most are invasive or not specifically focused on the optic nerve head (ONH), choroid or retinal circulation. Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF).

Methods: A confocal miniature flowmeter was fixed to a specially designed 3D rotating mechanical arm and adjusted on a rodent stereotaxic table in order to accurately point the laser beam at the retinal region of interest. The linearity of the LDF measurements was assessed using a rotating Teflon wheel and a flow of microspheres in a glass capillary. In vivo reproducibility was assessed in Wistar rats with repeated measurements (inter-session and inter-day) of retinal arteries and ONH blood velocity in six and ten rats, respectively. These parameters were also recorded during an acute intraocular pressure increase to 150 mmHg and after heart arrest (n = 5 rats).

Results: The perfusion measurements showed perfect linearity between LDF velocity and Teflon wheel or microsphere speed. Intraclass correlation coefficients for retinal arteries and ONH velocity (0.82 and 0.86, respectively) indicated strong inter-session repeatability and stability. Inter-day reproducibility was good (0.79 and 0.7, respectively). Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.

Conclusion: We have demonstrated that, while not adapted for ONH blood perfusion assessment, this device allows pertinent, stable and repeatable measurements of retinal blood perfusion in rats.

No MeSH data available.


Related in: MedlinePlus