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S. Villaron, M. Lopez, A. De la Mata, V. Saez, R. Reinoso, A. Corell, J. M. Herreras, M. Calonge, M. E. Stern, R. M. Corrales; Influence of Antiglaucoma Compounds on Ocular Surface Corneal and Conjunctival 2 Adrenergic Receptor Expression in vitro. Invest. Ophthalmol. Vis. Sci. 2009;50(13):4069.
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© ARVO (1962-2015); The Authors (2016-present)
Brimonidine, an adrenergic receptor (2AR) agonist used for the treatment of glaucoma, elicits conjunctivitis in 15% of patients by a mechanism that still remains elusive. Our group has reported the presence of 2AR in human conjunctiva and their up-regulation in cells exposed to inflammatory cytokines. To start investigating whether this drug could exert its mechanism of action by altering the expression of 2AR at the ocular surface, we studied the expression levels of 2AR in conjunctival and corneal cells treated with brimonidine.
Human conjunctival (IOBA-NHC) and corneal (HCE) cell lines were cultured for 24h and 48h under 3 different conditions: 1) control: supplemented culture medium (SCM); 2) SCM and brimonidine, 3) SCM and brimonidine plus timolol. The mRNA and protein expression of 2A, 2B and 2CAR was analyzed by real time RT-PCR, Western blotting, and flow cytometry. Cell viability, apoptosis, and cell cycle stage were also studied by flow cytometry.
The 2AAR gene and protein expression was up-regulated in both cell lines after 48h with either treatment. The mRNA expression of 2BAR and the gene and protein expression of 2cAR were down-regulated after 48h with either treatment and in both cell lines. The 2BAR protein expression was not altered. Both treatments affected viability, apoptosis, and cell cycle stage.
Both brimonidine and brimonidine plus timolol were able to alter the level of expression of 2AR in conjunctival and corneal cells. Whether this in vitro effect will have a clinical relevance remains to be confirmed.
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