Purpose. Laser trabeculoplasty (LTP) induces trabecular insert cell division and juxtacanalicular matrix metalloproteinase (MMP) expression. Treatment of 180 degrees produces responses for 360 degrees, thus implicating signal transmission by a soluble factor(s). To test this hypothesis, we evaluated trabecular responses to medium conditioned by LTP-treated human anterior segment explant cultures. Methods. Human anterior segment explants were given sham or clinical-parameter LTP treatments and allowed to condition culture medium for 8 hrs. This conditioned medium was then applied to fresh explants or trabecular cell cultures. 3H-thymidine incorporation into DNA or MMP protein or mRNA expression was then evaluated. Results. Trabecular insert cell division in explants is increased by exposure to 8-hr conditioned medium from LTP- but not sham-treated explants. Gelatinase B and stromelysin expression by trabecular cells exposed to LTP- but not sham-treatment medium were increased at 24-72 hrs. Alternative types of trabecular wounding did not mimic LTP-treatment. Hypotonic shock and sonication of trabecular meshworks did not release this LTP factor. Conclusion. The trabecular response to LTP involves the production rather than release of a factor(s), which can mediate both the trabecular insert cell division response and the MMP expression response by trabecular cells. This factor may have the potential to replace LTP-treatment as a therapy for glaucoma.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience