Background The cell layer of the ciliary epithelium is responsible for aqueous humor secretion and maintenance. Ion channels play an important role in these processes. The main aim of this study was to determine wheth...Background The cell layer of the ciliary epithelium is responsible for aqueous humor secretion and maintenance. Ion channels play an important role in these processes. The main aim of this study was to determine whether the well-characterized members of the Kvl family （Kv1.3） contribute to the Kv currents in ciliary epithelium. Methods New Zealand White rabbits were maintained in a 12 hours light/dark cycle. Ciliary epithelium samples were isolated from the rabbits. We used Western blotting and immunocytochemistry to identify the expression and location of a voltage-gated potassium channel Kvl.3 in ciliary body epithelium. Membrane potential change after adding of Kvl.3 inhibitor margatoxin （MgTX） was observed with a fluorescence method. Results Western blotting and immunocytochemical studies showed that the Kv1.3 protein expressed in pigment ciliary epithelium and nonpigment ciliary epithelium, however it seemed to express more in the apical membrane of the nonpigmented epithelial cells. One nmol/L margatoxin, a specific inhibitor of Kv1.3 channels caused depolarization of the cultured nonpigmented epithelium （NPE） membrane potential. The cytosolic calcium increased after NPE cell depolarization, this increase of cytosolic calcium was partially blocked by 12.5 μmol/L dantrolene and 10 μmol/L nifedipine. These observations suggest that Kv1.3 channels modulate ciliary epithelium potential and effect calcium dependent mechanisms. Conclusion Kv1.3 channels contribute to K＋ efflux at the membrane of rabbit ciliary epithelium.展开更多
In order to elucidate the effect of dexamethasone on the expression of transforming growth factor-betal （TGF-β1） in ciliary pigment epithelial （CPE） cells cultured in vitro, rabbit CPE cells were cultured in vitr...In order to elucidate the effect of dexamethasone on the expression of transforming growth factor-betal （TGF-β1） in ciliary pigment epithelial （CPE） cells cultured in vitro, rabbit CPE cells were cultured in vitro, treated with DMEM medium containing 0, 1 × 10^-8 , 5 × 10^-8 , 10 × 10^-8 and 50 × 10^-8 mol/L dexamethasone respectively for 5 days. The TGF-131 expression was detected by immunohistochemistry Supervision methods and analyzed semi-quantitatively by HMIAS-2000 image system. As opposed to in vivo, rabbit CPE cells expressed TGF-131 under cul- tured circumstance in vitro. The gray scales of the positive yellow staining in the groups of 1 × 10^-8 , 5 × 10^-8 , 10 × 10^-8 and 50 × 10^-8 mol/L dexamethasone were 136.57 ± 4.43, 140.20 ± 6. 10, 142. 98± 2. 99, 146.80±1.68 and 150.05 × 1.94 respectively. When the concentrations of dexamethasone were equal to or higher than 5 × 10^-8mol/L and, the expression of TGF-β1 was inhibited. 10^-7 mol/L dexamethasone showed a significant inhibition. It was suggested that CPE cells possess the potential ability of synthesizing and expressing TGF-β1. The inhibition of TGF-β1 expression by dexamethasone may be beneficial to the treatment of proliferative vitroretinopathy, also exert some influence on the secretion of aqueous humor and ciliary inflammation.展开更多
文摘Background The cell layer of the ciliary epithelium is responsible for aqueous humor secretion and maintenance. Ion channels play an important role in these processes. The main aim of this study was to determine whether the well-characterized members of the Kvl family （Kv1.3） contribute to the Kv currents in ciliary epithelium. Methods New Zealand White rabbits were maintained in a 12 hours light/dark cycle. Ciliary epithelium samples were isolated from the rabbits. We used Western blotting and immunocytochemistry to identify the expression and location of a voltage-gated potassium channel Kvl.3 in ciliary body epithelium. Membrane potential change after adding of Kvl.3 inhibitor margatoxin （MgTX） was observed with a fluorescence method. Results Western blotting and immunocytochemical studies showed that the Kv1.3 protein expressed in pigment ciliary epithelium and nonpigment ciliary epithelium, however it seemed to express more in the apical membrane of the nonpigmented epithelial cells. One nmol/L margatoxin, a specific inhibitor of Kv1.3 channels caused depolarization of the cultured nonpigmented epithelium （NPE） membrane potential. The cytosolic calcium increased after NPE cell depolarization, this increase of cytosolic calcium was partially blocked by 12.5 μmol/L dantrolene and 10 μmol/L nifedipine. These observations suggest that Kv1.3 channels modulate ciliary epithelium potential and effect calcium dependent mechanisms. Conclusion Kv1.3 channels contribute to K＋ efflux at the membrane of rabbit ciliary epithelium.
文摘In order to elucidate the effect of dexamethasone on the expression of transforming growth factor-betal （TGF-β1） in ciliary pigment epithelial （CPE） cells cultured in vitro, rabbit CPE cells were cultured in vitro, treated with DMEM medium containing 0, 1 × 10^-8 , 5 × 10^-8 , 10 × 10^-8 and 50 × 10^-8 mol/L dexamethasone respectively for 5 days. The TGF-131 expression was detected by immunohistochemistry Supervision methods and analyzed semi-quantitatively by HMIAS-2000 image system. As opposed to in vivo, rabbit CPE cells expressed TGF-131 under cul- tured circumstance in vitro. The gray scales of the positive yellow staining in the groups of 1 × 10^-8 , 5 × 10^-8 , 10 × 10^-8 and 50 × 10^-8 mol/L dexamethasone were 136.57 ± 4.43, 140.20 ± 6. 10, 142. 98± 2. 99, 146.80±1.68 and 150.05 × 1.94 respectively. When the concentrations of dexamethasone were equal to or higher than 5 × 10^-8mol/L and, the expression of TGF-β1 was inhibited. 10^-7 mol/L dexamethasone showed a significant inhibition. It was suggested that CPE cells possess the potential ability of synthesizing and expressing TGF-β1. The inhibition of TGF-β1 expression by dexamethasone may be beneficial to the treatment of proliferative vitroretinopathy, also exert some influence on the secretion of aqueous humor and ciliary inflammation.
