Abstract
Purpose: :
To examine the mechanism of injury caused by phacoemulsification to bovine corneal endothelial cells in culture.
Methods: :
In order to exclude the mechanical effects of the phacoemulsification, the cells were grown on a special Biofolie gas–permeable membrane. A frame holding the membrane with a confluent monolayer of cells was placed in a chamber with irrigation solution into which the phacoemulsification tip was introduced. The amount of apoptosis following the treatment was evaluated using the anti–Caspase 3 antibodies with the Histostain–Plus (AEC) kit. The degree of apoptosis following phacoemulsification and Hydrogen–Peroxide treatment were compared and the protective effect of Ascorbic acid was evaluated.
Results: :
Exposure to Phacoemulsification induced apoptosis of corneal endothelial cells. The amount of detected apoptotic cells increased with the incubation time following the treatment reaching maximal amounts after 48 h at which 333±29 per 1mm² were stained by the antibody compared to 23±5. The average number of apoptotic cells induced by exposure for 48h to H2O2 at concentrations of 50 and 100 µM was 345±6 and 376±1, respectively. Comparison between sham and exposure to phacoemulsification, when fixation is made after 48 h, reveals that the number of apoptotic cells increases significantly from 45±12 to 333±28 (P=1.4E–09). The addition of ascorbic acid (0.001 M), reduced the apoptotic cells count to 219±15 (P=5.1E–06). The reduction is even greater when the concentration is higher (0.01 M) – 129±29 (P=1.9E–08).
Conclusions: :
We established a new model of membranes covered with cultured bovine corneal endothelial cells. This model enables us to avoid the mechanical damage caused by turbulent currents heating the cells on hard plates and mimics the conditions in vivo. We have proved that exposure to phacoemulsification energy induces a cellular cascade leading to apoptosis and addition of ascorbic acid to the irrigation solution reduces significantly the amount of apoptotic cells probably due to its free radicals scavenging properties.
Keywords: apoptosis/cell death • cornea: endothelium • oxidation/oxidative or free radical damage