地塞米松对低渗诱导的人小梁细胞容积敏感性氯电流的影响

Effects of dexamethasone on human trabecular meshwork cell volume-sensitive chloride currents induced by hypotonic

目的:分析地塞米松对低渗诱导的人小梁细胞容积敏感性氯电流的影响,探讨容积敏感性氯通道(VACC)在激素性青光眼(GIG)发病中的可能机制。方法:人小梁细胞悬液接种于直径35mm塑料培养皿中单层生长,按培养液中是否含地塞米松分组,即正常培养液组和地塞米松培养1、3和7d组,共4组,采用全细胞膜片钳技术分别记录4组细胞在低渗状态下的氯电流密度值,比较各组数值的差异。结果:正常培养液组小梁细胞低渗刺激后,在+100和-100 mV电压钳钳制下,外向和内向电流密度值分别为(19.94±0.87)和(-6.53±0.41)pA/pF。地塞米松培养1、3和7d组的小梁细胞低渗刺激后,在+100和-100mV电压钳钳制下,外向和内向电流密度值分别为(19.39±1.40)和(-6.42±0.28)pA/pF、(17.97±2.35)和(-5.82±0.94)pA/pF、(17.16±1.16)和(-5.65±0.43)pA/pF。地塞米松培养1d组小梁细胞较正常培养液组低渗刺激后的外向和内向电流密度值减小,但差异无统计学意义(P>0.05);地塞米松培养3和7d组小梁细胞较正常培养液组小梁细胞低渗刺激后的外向和内向电流密度值明显减小(P<0.05)。结论:地塞米松导致体外培养的正常人小梁细胞容积敏感性氯电流密度值降低,进而影响小梁细胞容积调节,可能是导致GIG房水流出阻力增加的原因之一。

Objective To analyze the influence of dexamethasone in the hypotonic-induced volume-sensitive chloride currents in human trabecular meshwork cells,and to investigate the possible mechanism of volume-sensitive chloride channels（VACC）in the glucocorticoid-induced glaucoma（GIG）cases.Methods The human trabecular meshwork cells were seeded in 35 mm diameter plastic petri dishes,so that they could grow in monolayer.The cultured cells were divided into normal cell culture medium group and dexamethasone 1 d,3 d,7 d groups.The chlorine current density values of the cells in four groups were recorded respectively by the whole-cell patch-clamp technique. The differences among groups were compared.Results In normal group,after hypotonic stimulation,under＋100 and-100 mV voltage clamp,the outward and inward current density values of the trabecular cells were （19.94±0.87） and （-6.53±0.41）pA/pF.In dexamethasone 1 d,3 d,and 7 d groups,under the same condition,the outward and inward current density values of the trabecular cells were （19.39 ± 1.40）and （-6.42 ± 0.28）pA/pF, （17.97±2.35）and （-5.82±0.94）pA/pF,（17.16±1.16）and （-5.65±0.43）pA/pF.The trabecular cells＆amp;nbsp;cultured with dexamethasone for 1 d had lower outward and inward current density values under hypotonic stimulation compared with normal group,but there was no significant difference （P〉0.05）.The trabecular cells cultured with dexamethasone for 3 d and 7 d,when compared with normal group,had significantly lower outward and inward current density values under hypotonic stimulation （P〈0.05 ）. Conclusion Dexamethasone could reduce the volume-sensitive chloride current in trabecular meshwork cells,which would affect trabecular meshwork cell volume adjustment.This would possibly cause the increase of the aqueous humor outflow resistance among GIG cases.