Abstract
Background and Objective
We investigated the levels of matrix metalloproteinase‐2 (MMP‐2), which has been implicated in various vitreoretinal diseases, in the retina after laser photocoagulation (LPC).
Materials and Methods
The time course of MMP‐2 expression in 2‐day‐old chicken retinas before and 6 hours, 12 hours, 1 day, 2 days, 4 days, 8 days, 16 days, and 32 days after LPC was determined by real‐time PCR and gelatin zymography. The basal level of MMP‐2 in the retina and vitreous was also measured by gelatin zymography. MMP‐2 localization in the retina was examined by immunohistochemistry. The localization of MMP‐2 mRNA was determined by fluorescent in situ hybridization. The internal limiting membrane (ILM) was observed by scanning electron microscopy.
Results
MMP‐2 mRNA expression in the retina peaked at day 4, but gelatin zymography showed that MMP‐2 peaked 6 hours after LPC and the significant increase in the level of active MMP‐2 lasted for more than 4 days. The concentration of MMP‐2 in the vitreous was significantly higher than that in the retina. A distinct MMP‐2 signal around the ILM was identified 6 hours after LPC, but MMP‐2 mRNA was not detected there. Electron microscopy showed a damaged retinal surface after LPC.
Conclusion and Outlook
The significant increase in retinal MMP‐2 which lasted for more than 4 days after LPC may be induced by influx from the vitreous into the retina. This MMP‐2 dynamics may contribute to pathological processes in the retina after LPC. Lasers Surg. Med. 42:433‐441, 2010. © 2010 Wiley‐Liss, Inc.