Figure 4. Dexamethasone increases zonula occludens 1 and connexin 43 expression in trabecular meshwork cells. Western blot analysis showed the expression of zonula occludens 1 (ZO-1) and connexin 43 (Cx43) protein in trabecular meshwork (TM) cells. NTM cells express the ZO-1 α– isoform and Cx43 protein, whereas GTM cells express both ZO-1 isoforms and Cx43 protein. Treatment with 10⁻⁷ mol/l dexamethasone (Dex) caused a time-dependent increase in both ZO-1 and Cx43, with peak expression at 4 and 5 days, followed by a gentle decline at 6 days; however, the levels of these proteins were not at the basal level after 7 days. GAPDH was used as the internal loading control and n=3.