Abstract
Purpose:
Glucocorticoids (GCs) are known to cause elevated intraocular pressure (IOP) and even glaucoma in 40% of the general population after long-term application. In contrast, more than 90% of the primary open angle glaucoma (POAG) patients will develop GC-induced IOP elevation. Since GCs are frequently used as a powerful anti-inflammatory agent, it is important to understand how GCs selectively affect certain population. Also, the clinical and pathological presentations/findings of GC-induced glaucoma (GIG) are very similar to POAG. The major pathological changes in GIG reside in the trabecular meshwork (TM), which contribute to elevated IOP. This study is trying to develop a method that enables us to establish bovine TM (BTM) cell strains with known GC responsiveness, and to compare the biological difference between these two BTM populations.
Methods:
Paired bovine eyes were obtained from local abattoir. One eye was used for perfusion culture and treated with 100nM dexamethasone (DEX) dissolved in ethanol. The fellow eye was not subjected to perfusion but was used for BTM cell strain establishment. To establish BTM cell strains, the TM tissue was carefully dissected from the fellow eye and placed in cultured dishes. After several days, BTM cells would migrate from the tissue to the dish surface. Based on whether the DEX treated, perfusion cultured eye developed IOP elevation (more than 2.82mmHg from baseline), the cell strain established from the fellow eye was defined as a DEX-responder/non-responder cell strainer. GC receptor (GR) signaling activity and the formation of cross-linked actin networks (CLANs) were compared between the two groups.
Results:
As we reported previously, only a subpopulation of cow eyes developed elevated IOP upon DEX treatment during perfusion culture. The cell strains that we established were morphologically similar, whether it was a responder or non-responder cell strain. We used a lentiviral luciferase assay reporter vector to compare GR pathway activity and found the responder cells had higher GR signaling activity upon DEX stimulation (n=5, p<0.05). The formation of CLANs in the BTM cell strains that we studied did not show significant difference (2 strains of either group, p<0.05).
Conclusions:
We developed a useful method to establish BTM cell strains with known GC responsiveness. Further studies are needed to further compare the two populations of cells.
Keywords: 735 trabecular meshwork •
568 intraocular pressure •
633 outflow: trabecular meshwork