Summary: The current study aimed to design and test a white light induction system using energy efficient LEDs capable of producing photoreceptor degeneration in a dose-dependent manner.
Abstract
INTRODUCTION: The current study aimed at designing and testing a white light induction system using energy efficient LEDs (Fig. 1) capable of producing photoreceptor degeneration in a dose-dependent manner.
MATERIALS AND METHODS: Male and female Balb/cJRj mice (Janvier Labs), 7 and 13 weeks old, were exposed to 4,100 Lux (50%), or 6,200 Lux (75%) for 30 min after overnight dark adaptation. Scotopic ERG (Celeris, Diagnosys) and SD-OCT (Envisu R2200, Leica Microsystems) were performed at baseline and 7 days after light exposure. ERG amplitudes were analyzed in the Espion v6 software (v6.64.9. Diagnosys) and retinal thickness was analyzed from the SD-OCT scans using a proprietary 6-Layer segmentation algorithm (Fig. 2).
Figure 1. Overview of the LED white light damage system, and graphical representation of the white light spectra and intensity from the RGB+CCT 24 V CRI 98 LED strips.
Figure 2. Example images from the 6-Layer segmentation algorithm from the Naïve and white light-induced mice at two different intensities, 4,100 and 6,200 Lux.
RESULTS:
Significantly decreased photoreceptor response in conjunction with significantly reduced outer retina thickness (Fig. 3)
Figure 3. 7-week-old male mice were exposed to 4,100 or 6,200 Lux for 30 min. Data are presented as mean ± SD from 6-10 mice per group. Data was analyzed by one-way ANOVA or Kruskal-Wallis. Significance vs Naïve was analyzed by Tukey’s or Dunn’s post hoc. **, P < 0.01; ***, P < 0.001.
Females had minor reduction on the outer retinal thickness without affecting the photoreceptor response (Fig. 4)
Figure 4. 13-week-old male and female mice were exposed to 4,100 Lux for 30 min. Data are presented as mean ± SD from 9 mice per group. Data was analyzed by unpaired t-test or Mann-Whitney. Significance vs Naïve. *, P < 0.05; **, P < 0.01; ***, P < 0.001
CONCLUSIONS:
1. The newly designed system is capable of inducing dose-dependent damage concentrated on the photoreceptor layer with a high-throughput.
2. Females did not show photoreceptor functional deficits. Thus, these settings should be limited to males.
3. Next, we aim at identifying light intensity and length of exposure for females as well as using this system to induce light damage in rats
Authors: Marc Cerrada-Gimenez | Leena Tähtivaara | Anni Tenhunen | Xavier Ekolle | Birgitta Lappeteläinen | Ville Jokinen | Anne Mari Haapaniemi | Anna Mari Koponen | Päivi Partanen | Anni Kolehmainen | Nerija Kvietkauskienė | Simas Bijeikis | Maria Vähätupa | Jeffrey A. Jamison
Keywords: AMD, ERG, Light Damage