Abstract
Purpose:
Neuronal ceroid lipofuscinoses (NCL) are early onset lysosomal storage disorders characterized by vision loss, mental and motor deficits, and spontaneous seizures. Notably, massive accumulations of autofluorescent material in neurons lead to progressive neuronal degeneration and cell loss. Our previous studies on CLN6nclf mice revealed that progressive retinal degeneration starts before one month of age and is accompanied by microglia activation. The aim of our study was to examine the effect curcumin, luteolin and DHA supplementation would have on microglia activation and retinal/brain degeneration in these mice.
Methods:
CLN6nclf mice were supplemented with 0.6% curcumin, luteolin and 5% DHA for 30 weeks starting at 4 weeks of age. Visual acuity and retinal function was determined by measuring the optokinetic response in an Optomotry system and by use of electroretinography, respectively. Microglial morphology and migration was analyzed in retinal, optic nerve and brain tissues by immunohistochemistry. Retinal and brain neurodegenerative gene expression markers were compared to see if there was an overall beneficial effect.
Results:
Our data shows that supplemented CLN6nclf mice have a significant improvement in optokinetic and ERG response compared to control CLN6nclf mice which were given a standard diet. Histological analyses of the retina reveal a mixed population of active and resting microglia in the supplemented mice compared to mostly active microglia found in the control mice. The same can be seen in the brain tissues. Interestingly, there is a greater preservation of photoreceptor in DHA supplemented mice compared to the other groups. A comparison of gene expression markers in the retina and cortex/cerebellum revealed that the tissues were affected differently by the supplementation.
Conclusions:
Our results show that curcumin, luteolin and DHA have beneficial effects on supplemented mouse retina and brain. The mixed populations of microglia seen in the retina suggest that these supplements can to some extent attenuate microglia activation coinciding with a more functional retina. Furthermore, these anti-inflammatory substances could have further beneficial effects when paired with different therapies.
Keywords: 595 microglia •
696 retinal degenerations: hereditary •
555 immunomodulation/immunoregulation