Purchase this article with an account.
U. Lonngren, S. Mayor–Torroglosa, U. Näpänkangas, I. Cánovas, M. Vidal–Sanz, F. Hallböök; The Expression of Neurotrophic Factors and Their Receptors in Retina After Unilateral Administration of Brimonidine in Eyes of Normal Rats . Invest. Ophthalmol. Vis. Sci. 2006;47(13):4843.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To study the effect of unilateral topical administration of the α2–adrenergic receptor agonist brimonidine, known to be neuroprotective for ganglion cells in injured rat retina, on the mRNA expression of Bdnf, Cntf and Fgf2 and their receptors (TrkB, Cntfrα, Fgfr1) in both ipsi– and contralateral retinas of normal rats.
Adult Sprague Dawley rats were treated topically on one eye with 2x5µl brimonidine (0.005 – 0.5%) or vehicle (0.9% NaCl). Retinas from left and right eyes were collected 12 hours, 1, 3, or 7 days after treatment and analyzed using qRT PCR. The results were normalized to ß–actin expression and related to normal retinal mRNA levels. Retinas from six animals were pooled and the left (treated) and right (untreated) retinas were analysed separately. In addition, expression levels of the ganglion cell marker Thy–1 were analyzed.
The unilateral treatment evoked a similar response–pattern in both retinas. A sustained increase of Bdnf, Cntf and Fgf2 mRNA levels was seen in both retinas after the 0.5% brimonidine treatment. With the clear exception for Fgf2, a dose–dependent response was seen with only minor alterations in the expression levels at the lower brimonidine (<0.5%) concentrations. Surprisingly, the distinct increase of Fgf2 mRNA levels (2–6 –fold) at all time points were similarly evoked by treatment with any of the concentrations of brimonidine as well as with vehicle. The receptor mRNA levels or Thy1 levels were not markedly changed after brimonidine treatment.
Unilateral topical administration of brimonidine has a similar effect on both the ipsi– and contralateral retinas. This implies that topical administration has a systemic effect and reaches the other retina. Bdnf and Cntf mRNA levels increase in both retinas after treatment with 0.5% brimonidine but not vehicle, suggesting that upregluation of neurotrophic factors is a part of its neuroprotective effect. Our results also show that Fgf2 mRNA levels increase similarly after topical administration of brimonidine and vehicle. This demonstrates that alterations in retinal Fgf2 mRNA levels are likely the result of an unspecific stress–induced response after the handling during topical administration.
This PDF is available to Subscribers Only