Comparison of visual function in pigmented and albino rats by electroretinography and visual evoked potentials

Heiduschka, Peter; Schraermeyer, Ulrich

doi:10.1007/s00417-008-0895-3

Cited by 44 publications

(31 citation statements)

References 46 publications

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“…Some studies have reported ERG differences in animal models based on fundus pigmentation levels [22][23][24][25][26][27][28], and others have compared human participants [2-6, 29, 30]. Our findings that some ERGs are larger from those with lighter eyes are in keeping with previous studies [2][3][4][5][6][7].…”

Section: Discussionsupporting

confidence: 95%

Light- and dark-adapted electroretinograms (ERGs) and ocular pigmentation: comparison of brown- and blue-eyed cohorts

et al. 2010

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This study characterizes differences in human ERGs based on ocular pigmentation. Light- and dark-adapted luminance-response (LR) series for a-, b- and i-waves and light-adapted oscillatory potentials (OPs) were recorded in 14 healthy volunteers (7 blue-eyed Caucasians; 7 brown-eyed Asians, aged 20-22 years). Amplitude interpolations were by logistic growth (Naka-Rushton), Gaussian or the combined 'photopic hill' functions. Implicit times (IT) for dark-adapted a- and b-waves, and for light-adapted a-, b- and i-waves were earlier in the blue-eyed group than in the brown-eyed group across all flash strengths (P < 0.05). For dark-adapted ERGs, saturated a-wave amplitude was larger for blue eyes (397 vs. 318 μV, P < 0.05) as was the a-wave to strong flash (10 cd·s/m(2); 357 vs. 293 μV, P < 0.05) and the b-wave to ISCEV standard 0.01 (354 vs. 238 μV, P < 0.05). Light-adapted b-waves for midrange flash stimuli were much larger for the blue-eyed group (photopic hill, Gaussian peak: 155 vs. 82 μV, P < 0.001) with no difference in saturated amplitudes. Similarly, interpolated i-wave amplitudes were larger (48 vs. 18 μV, P < 0.01). For a light-adapted 2.6 stimulus, a- and b-waves were larger for the blue-eyed group (52 vs. 39 μV; 209 vs. 133 μV, P < 0.01) as were OP4 and OP5 (37.2 vs. 15.6 μV; 47.5 vs. 22.2 μV, P < 0.01), but OP1-OP3 did not differ. ERGs have shorter ITs in people with blue irides than in those with dark pigmentation. Amplitude differences are highly non-linear and substantially larger from eyes with light pigmentation for components thought to be associated with the OFF retinal pathways.

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Section: Discussionsupporting

confidence: 95%

Light- and dark-adapted electroretinograms (ERGs) and ocular pigmentation: comparison of brown- and blue-eyed cohorts

et al. 2010

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“…We used a visual electrodiagnostic system (UTAS-E3000, LKC Technologies, Gaithersburg, MD, USA) to measure photoptic FVEP. Previous studies had shown no significant differences in latency between photoptic and scotopic VEPs in Wistar rats, and a smaller amplitude in photoptic VEPs compared with the wave of scotopic VEPs (Heiduschka and Schraermeyer, 2008; Chang et al, 2014). We defined the first positive wavelet as the P1 wave (Young et al, 2012), and compared the latency of the P1 wave and the amplitude of the P1-N2 wave in each group ( n =6 rats in each group) to evaluate visual function.…”

Section: Methodsmentioning

confidence: 64%

Early applications of granulocyte colony-stimulating factor (G-CSF) can stabilize the blood-optic nerve barrier and further ameliorate optic nerve inflammation in a rat model of anterior ischemic optic neuropathy (rAION)

Wen

Huang

et al. 2016

Disease Models &Amp; Mechanisms

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Granulocyte colony-stimulating factor (G-CSF) was reported to have a neuroprotective effect in a rat model of anterior ischemic optic neuropathy (rAION model). However, the therapeutic window and anti-inflammatory effects of G-CSF in a rAION model have yet to be elucidated. Thus, this study aimed to determine the therapeutic window of G-CSF and investigate the mechanisms of G-CSF via regulation of optic nerve (ON) inflammation in a rAION model. Rats were treated with G-CSF on day 0, 1, 2 or 7 post-rAION induction for 5 consecutive days, and a control group were treated with phosphate-buffered saline (PBS). Visual function was assessed by flash visual evoked potentials at 4 weeks post-rAION induction. The survival rate and apoptosis of retinal ganglion cells were determined by FluoroGold labeling and TUNEL assay, respectively. ON inflammation was evaluated by staining of ED1 and Iba1, and ON vascular permeability was determined by Evans Blue extravasation. The type of macrophage polarization was evaluated using quantitative real-time PCR (qRT-PCR). The protein levels of TNF-α and IL-1β were analyzed by western blotting. A therapeutic window during which G-CSF could rescue visual function and retinal ganglion cell survival was demonstrated at day 0 and day 1 post-infarct. Macrophage infiltration was reduced by 3.1- and 1.6-fold by G-CSF treatment starting on day 0 and 1 post-rAION induction, respectively, compared with the PBS-treated group (P<0.05). This was compatible with 3.3- and 1.7-fold reductions in ON vascular permeability after G-CSF treatment compared with PBS treatment (P<0.05). Microglial activation was increased by 3.8- and 3.2-fold in the early (beginning treatment at day 0 or 1) G-CSF-treated group compared with the PBS-treated group (P<0.05). Immediate (within 30 mins of infarct) treatment with G-CSF also induced M2 microglia/macrophage activation. The cytokine levels were lower in the group that received immediate G-CSF treatment compared to those in the later G-CSF treatment group (P<0.05). Early treatment with G-CSF stabilized the blood–ON barrier to reduce macrophage infiltration and induced M2 microglia/macrophage polarization to decrease the expressions of pro-inflammatory cytokines in this rAION model.

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“…On the first day, the recording was repeated three times (during the same anaesthetic session). The recording method was derived from a combination of the protocols used in the literature [3,5,10,17]. Briefly, the animals were anaesthetised, placed in a dark room and allowed to adapt to darkness for 5 min (dark adaptation was repeated before each recording session).…”

Section: Vep Recording Proceduresmentioning

confidence: 99%

“…However, it has been reported that the electrode positioning significantly affected the rat VEP waveform [6]. In addition, different visual stimulators have been used to generate VEP responses, including strobe photostimulator [6][7][8], full-field (Ganzfeld) system [3,[9][10][11] and single light-emitting diode (LED) [12].…”

Section: Introductionmentioning

confidence: 99%

Improving reproducibility of VEP recording in rats: electrodes, stimulus source and peak analysis

et al. 2011

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The aims of this study were to evaluate and improve the reproducibility of visual evoked potential (VEP) measurement in rats and to develop a mini-Ganzfeld stimulator for rat VEP recording. VEPs of Sprague-Dawley rats were recorded on one randomly selected eye on three separate days within a week, and the recordings were repeated three times on the first day to evaluate the intrasession repeatability and intersession reproducibility. The VEPs were recorded with subdermal needle and implanted skull screw electrodes, respectively, to evaluate the effect of electrode configuration on VEP reproducibility. We also designed a mini-Ganzfeld stimulator for rats, which provided better eye isolation than the conventional visual stimuli such as flash strobes and large Ganzfeld systems. The VEP responses from mini-Ganzfeld were compared with PS33-PLUS photic strobe and single light-emitting diode (LED). The latencies of P1, N1, P2, N2, and P3 and the amplitude of each component were measured and analysed. Intrasession and intersession within-subject standard deviations (Sw), coefficient of variation, repeatability (R95) and intraclass correlation coefficient (ICC) were calculated. The VEPs recorded using the implanted skull electrodes showed significantly larger amplitude and higher reproducibility compared to the needle electrodes (P<0.05). The mini-Ganzfeld stimulator showed superior repeatability and reproducibility in VEP recording. The intra/intersession ICCs of latency were 0.85/0.70 for mini-Ganzfeld, 0.72/0.62 for PS33-PLUS and only 0.59/0.42 for single LED. The latencies of the early peaks (N1 and P2) demonstrated better reproducibility than the later waves. The mean intrasession and intersession ICCs were 0.96 and 0.86 for the early peaks. Using a combination of skull screw electrodes, mini-Ganzfeld stimulator and early peak analysis, we achieved a high reproducibility in the rat VEP measurement. The latencies of the early peaks of rat VEPs were more consistent, which may be due to their generation in the primary visual cortex via the retino-geniculate fibres.

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Comparison of visual function in pigmented and albino rats by electroretinography and visual evoked potentials

Abstract: ERG b-wave amplitudes are markedly decreased in Wistar rats, which requires further investigation. As the b/a and OP/a ratios were also decreased in Wistar rats, it can be suggested that post-receptoral processing, in particular, is impaired in albino animals.

Cited by 44 publications

References 46 publications

Light- and dark-adapted electroretinograms (ERGs) and ocular pigmentation: comparison of brown- and blue-eyed cohorts

Light- and dark-adapted electroretinograms (ERGs) and ocular pigmentation: comparison of brown- and blue-eyed cohorts

Early applications of granulocyte colony-stimulating factor (G-CSF) can stabilize the blood-optic nerve barrier and further ameliorate optic nerve inflammation in a rat model of anterior ischemic optic neuropathy (rAION)

Improving reproducibility of VEP recording in rats: electrodes, stimulus source and peak analysis

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