Keratocyte Loss in Anterior Stroma of the Rabbit Cornea after Photorefractive keratectomy

ABSTRACT

This study evaluated the response of the anterior stromal keratocytes in Rabbits following deepithelialization and 3 diopter(37micrometer)- and 12 diopter(99micrometer) PRK. The corneal sections obtained from the operated area on postoperative 3, 7 and 14 days were stained with hematoxylin and eosin. Keratocyte apoptosis were monitored using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling(TUBEL) staining with ApopTag kit for the corneal section obtained on postoperative 3 day. The corneal haze on postoperative 14 day were graded using a slit lamp biomicroscopy. The number of anterior stromal keratocytes had decreased significantly and positive TUNEL staining was noted in the anterior stroma after PRK and deepithelialization campared with that of controls. The decreased keratocyte numbers were recovered on postoperative 7 day after deepithelialization and on postoperative 14 day after PRK. The newly appeared deratocytes were pyknotic, variable-shaped and crosswisely oriented in appearance, and especially increased following 12 diopter PRK. Both the keratocyte loss and corneal haze grading was increased related to the increased ablation depth after PRK. In conclusion, the loss of anterior stromal keratocytes after PRK is mediated by apoptosis and followed by reactive cellular proliferation might be a important role in the corneal haze.