과산화수소와 동결에 의해 유도된 생쥐와 소 수정란의 사멸에 있어서 칼륨 통로의 역할

Abstract

Programmed cell death or apoptosis is associated with changes in K+ concentration in many cell types. Recentstudies have demonstrated that two-pore domain K+ (K2P) channels are involved in mouse embryonic development andapoptotic volume decrease of mammalian cells. In cerebellar granule neurons that normally undergo apoptosis duringthe early developmental stage, TASK-1 and TASK-3, members of K2P channels, were found to be critical for celldeath. This study was performed to identify the role of K+ channels in the H2O2-induced or cryo-induced cell deathof mouse and bovine embryos. Mouse and bovine two-cell stage embryos (2-cells) exposed to H2O2 for 4 h sufferedfrom apoptosis. The 2-cells showed positive TUNEL staining. Treatment with high concentration of KCl (25mM)inhibited H2O2-induced apoptosis of 2-cells by 19%. Cryo-induced death in bovine blastocysts showed positive TUNELstaining only in the cells near the plasma membrane. Cryoprotectant supplemented with 25 mM KCl reduced apoptosisslightly compared to cryoprotectant supplemented with 5 mM KCl. However, the combination of antioxidants (β-mercaptoethanol) with 25 mM KCl significantly decreased the rate of H2O2-induced and cryo-induced apoptosiscompared to treatments with only antioxidants or 25 mM KCl. These results show that blockage of K+ channel effluxfor a short-time reduces H2O2- and cryo-induced apoptosis in mouse and bovine embryos. Our findings suggest thatapoptosis in mouse and bovine embryos might be controlled by modulation of K+ channels which are highly expressedin a given cell type.