The drugs, commonly used to treat rheumatoid arthritis, could be an alternative to surgery or beta-blocker eye drops currently used to reduce ocular pressure.
For the study, mice underwent laser irradiation in one eye. The irradiation induced intraocular hypertension, a risk factor for glaucoma and resultant damage to oligodendrocytes and retinal ganglion cells.
Levels of TNF-alpha were almost five times higher in the retinal tissue of eyes with ocular hypertension than control eyes. Ocular hypertension was also associated with elevated levels of microgilia cells, which are part of the immune defence of the eye.
Examination of the retina showed that in eyes with induced ocular pressure, oligodendrocytes were being destroyed resulting in a progressive loss of retinal ganglion cells.
In mice lacking genes that encode TNF-alpha or its receptor TNFR2, this process did not happen.
Similarly, loss of oligodendrocytes and retinal ganglion cells was prevented if mice were given TNF-alpha blockers.
The researchers concluded that TNF-alpha provides an essential link between ocular hypertension and retinal ganglion cell loss in vivo.
Co-author of the study, Dr Joan Miller, chief of ophthalmology at the Massachusetts Eye and Ear Infirmary, said: ‘It might be possible to put slow-release TNF-alpha inhibitors just outside the eye.’
Concerns over the long-term effects of TNF-alpha blockers mean an alternative treatment needs to be developed.
