Calcium homeostasis in early hamster preimplantation embryos.
Calcium homeostasis in early hamster preimplantation embryos.
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早期仓鼠植入前胚胎中的钙稳态。
DOI：
10.1095/biolreprod59.4.1000
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发表时间：
1998
影响因子：
3.6
通讯作者：
Bavister,BD
中科院分区：
文献类型：
--
作者：
Lane,M;Bavister,BD
在受精完成之前，1-细胞仓鼠胚胎在培养中的发育还不是很清楚。在本研究中，观察到在原核形成前(卵子激活后3h)仅培养6h的这些早期1-细胞胚胎的细胞内游离钙水平(194.3±3.1nM)显著高于在原核形成后9h从输卵管收集的1-细胞胚胎(134.2±6.8nM)。细胞内游离钙水平升高的培养3h PEA胚胎不仅发育能力低于PEA 9h时采集的胚胎，而且胞质线粒体分布受损(培养胚胎为0.62±0.06，体内发育胚胎为0.44±0.04)，乳酸代谢降低(培养胚胎为2.93±0.22pmoL/3h，体内发育胚胎为5.37±0.36)。这种线粒体分布和功能的损害，以及3h PEA胚胎在培养中发育的减少，似乎与调节细胞内钙稳态的能力有关。增加培养基镁浓度、钙通道阻滞剂硝苯地平或维拉帕米或细胞内钙离子螯合剂可降低细胞内游离钙水平。所有这些处理也促进了3h的PEA胚胎发育到桑椹/囊胚阶段，并防止了线粒体组织和功能的损害。相反，低中镁和高钙浓度的培养会增加细胞内游离钙水平，导致发育迟缓和线粒体功能降低。因此，从输卵管中取出早期胚胎似乎会导致无法调节细胞内钙水平。随着镁浓度的增加，硝苯地平和维拉帕米抑制L门控的钙通道，可能是这些通道调控的丧失，改变了钙稳态，导致发育能力受损。
The development in culture of 1-cell hamster embryos prior to the completion of fertilization is not well understood. In this study it was observed that culture for only 6 h of these early 1-cell embryos collected before pronuclei formation (3 h post-egg activation; PEA) significantly increased intracellular free calcium levels (194.3 ± 3.1 nM) compared to levels in similarly aged 1-cell embryos collected from the oviduct at 9 h PEA, after pronuclei formation is complete (134.2 ± 6.8 nM). Not only was the developmental competence of cultured 3-h PEA embryos with elevated intracellular free calcium levels compromised as compared with that of embryos collected from the oviduct at 9 h PEA; these embryos also had impaired cytoplasmic mitochondrial distribution (ratio of 0.62 ± 0.06 for cultured embryos compared to 0.44 ± 0.04 for in vivo-developed embryos) and decreased lactate metabolism (2.93 ± 0.22 pmol/embryo per 3 h for cultured embryos compared to 5.37 ± 0.36 for in vivo-developed embryos). This impairment in mitochondrial distribution and function and reduced development in culture by 3-h PEA embryos appears related to the ability to regulate intracellular calcium homeostasis. Intracellular free calcium levels were reduced by culture with increased medium magnesium concentrations, calcium channel inhibitors nifedipine or verapamil, or an intracellular calcium chelator. All of these treatments also stimulated development of 3-h PEA embryos to the morula/blastocyst stages and prevented impairment in mitochondrial organization and function. Conversely, culture with low medium magnesium and high calcium concentrations that increased intracellular free calcium levels resulted in low development and reduced mitochondrial function. Therefore, it appears that removal of the early embryo from the oviduct results in an inability to regulate intracellular calcium levels. As increased magnesium concentrations, nifedipine, and verapamil inhibit L-gated calcium channels, it may be a loss of regulation of these channels that alters calcium homeostasis resulting in impaired developmental competence.