gms | German Medical Science

Purpose: Hypothermia is known to be protective against ischemia in different tissues. Nevertheless hypothermia as neuroprotective mechanism has not been investigated so far on retinal ganglion cells, which are the most vulnerable cells of the retina against ischemia.

Methods: Enucleated bovine eyes were stored for different periods of time (10 minutes, 100 minutes and 340 minutes) at 21°C and 37°C. Afterwards whole mounts of the retina were prepared and either directly analyzed by measuring the spontaneous retinal ganglion cell potentials with a 256 multielectrode array or cultivated for another 24 hours as an organotypic culture. After the cultivation the Thy-1 mRNA expression was measured by Real-Time-PCR and immunohistochemistry (Brn3a- and DAPI staining) was performed on cryo sections to evaluate the number of living retinal ganglion cells.

Results: The spontaneous retinal ganglion cell potentials and the Thy-1 mRNA expression of the eyes which were stored at 21°C did show significantly more potentials respectively higher Thy-1 mRNA expression than the ones stored at 37°C after the different periods of time. Furthermore the eyes which were stored for 340 minutes at 21°C even showed better results than the eyes which were stored for only 100 minutes at 37°C concerning the spontaneous retinal ganglion cell potentials and the Thy-1 mRNA expression.

Conclusions: Hypothermia very strongly protects retinal ganglion cells against ischemia.