Abstract
Purpose: :
To investigate the role that Müller cell reactivity plays on photoreceptor cell survival in culture.
Methods: :
Experiment 1: Four separate sets of Müller cell cultures were prepared from the central and peripheral retinas of the 3 m (n=3) and 24 m (n=3) old Fischer 344 rats. These were co-cultured with photoreceptor cells from 3 month old Fishcer 344 rats. After 10 days, photoreceptor cell viability was assessed in the co-cultures. Experiment 2: Four separate sets of Müller cell cultures were prepared from the central and peripheral retinas of the 3 m (n=3) and 24 m (n=3) old Fischer 344 rats. Conditioned medium from each of these cultures was added to 5 day old photoreceptor cell cultures of 3 m old Fischer 344 retinas and cell survival was assessed after 5 more days. From previous studies based on glial fibrillary acidic protein expression, Müller cell reactivity was designated in the following fashion: 3m central = normal; 3 m old peripheral = mildly reactive; 24 m old central = moderately reactive; and 24 m old peripheral retina severely reactive.
Results: :
For experiment 1, photoreceptor cells co-cultured with Müller cells from 3 m old peripheral retinas showed greater survival rates (p < 0.019) than all other groups. For experiment 2, the only statistical difference seen was a higher photoreceptor cell survival rate for those cultured with conditioned media from 24 month old Müller cells versus those from 3 m old Müller cells (p = 0.041).
Conclusions: :
Previous studies have shown that Müller cell reactivity increases in the area of photoreceptor cell degeneration and may actually precede it in the Fischer 344 rat. From our experiments, Müller cells seem to play a role in photoreceptor cell survival due to the secretion of unknown factors related to their reactive state and also possibly to a mechanism involving cell-to-cell contact.
Keywords: Muller cells • retinal degenerations: cell biology • photoreceptors