Abstract
Purpose::
Recently, a mouse model for juvenile NCL (JNCL, Batten's disease) has been described exhibiting an early and progressive neurologic disease (Cotman et al., 2002). Life expectancy is only moderately decreased. However, the morphological changes of the retina were discreet. As in humans suffering from JNCL retinal dystrophy is an early sign of the disease and progressively leads to blindness we were interested in the retinal function of the mouse model (Cln3Δex7/8-mice).
Methods::
5 Cln3Δex7/8-mice (-/-) and 5 controls (+/+) have been examined by Ganzfeld electroretinograms (ERGs). Scotopic and photopic ERGs were performed in the anaesthetized mice. A-, b, and c-waves were analyzed. The age of the mice was 3, 6, 11 and 14 months.
Results::
At the age of 3 months, there were no detectable differences neither between the scotopic ERG a- and b-waves of knock-ins and controls nor between the cone-responses. However, the cone responses had a mild attenuation of the oscillations. With 6 months, in -/- rod responses declines without exhibiting singnificant differences compared to +/+. At 11 months of age, all ERG-responses show a severe attenuation of amplitudes, and at 14 months all responses show significant differences in amplitudes. The c-wave amplitudes showed varying results maybe due to the known variability of this kind of response. Confocal microscopy exhibits ATPase subunit c-reactive deposits in ONL, INL and ganglion cell layer detected by immunostaining. Interestingly this was found as early as 8 days after birth. By electron microscopy, fingerprint inclusions typical for JNCL were found in the ganglion cells (Cotman et al. 2002).
Conclusions::
Although showing basically the same features as human patients the mouse model for JNCL (Cln3Δex7/8-mice) exhibits a much milder form of the disease. However, the retinal phenotype is discernable so that testing of retinal function allows to monitor experimental therapeutic interventions.
Keywords: electroretinography: non-clinical • retinal degenerations: hereditary • transgenics/knock-outs