[Histopathologic and immunohistochemical studies on retina after laser photocoagulation]

To observe the histopathologic and immunohistochemical changes and reparable process of retina after laser photocoagulation in order to provide a theoretical basis of laser treatment for fudus diseases.

Normal retina was photocoagulated using I-, II-, III-grade photic spot after the signing of informed consent of 7 patients who were suffering from orbital malignant tumors and in need of exenteration. The retinae from removed eyeballs were fixed with formalin, imbedded in paraffin and stained by H. E. The SP immunohistochemical method was adopted using antibodies of S-100, GFAP, NSE,and NF label.

By histopathologyical examination, 1 day after photocoagulation with I-grade photic spot, the retinal pigment epithelium (RPE) cells, photoreceptors and cells in outer nuclear layer were edematous and necrotic, and decreased in number; with II-grade photic spot, many RPE cells, photoreceptors and cells in outer nuclear layer were lysed and destroyed; with III-grade photic spot, all layers of the retina were severely damaged. 3 days after photocoagulation, retinal edema was relieved. RPE and glial cells started proliferating. 7 days after photocoagulation, RPE and glial cells proliferated obviously to cover the destroyed areas. By immunohistochemistry, 3-7 days after photocoagulation, S-100 and GFAP were seen stained in the damage areas of photic spot. 1-7 days after photocoagulation, NSE and NF were found unstained in the photic spot.

The above data indicated that different laser photic spots resulted in various degrees of damage to the retina. The destroyed regions were repaired by proliferative RPE and glial cells. Immunohistochemistry confirmed that proliferative gial cells repaired damaged retina, and neurons and nerve fibers could not regenerate. Laser could treat different retinal diseases.