Hyperthermia effects on cytosolic [Ca2+]: analysis at the single cell level by digitized imaging microscopy and cell survival.
Hyperthermia effects on cytosolic [Ca2+]: analysis at the single cell level by digitized imaging microscopy and cell survival.
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发表时间：
1991
期刊：
影响因子：
11.2
通讯作者：
R. Mikkelsen;L. Reinlib;M. Donowitz;D. Zahniser
中科院分区：
文献类型：
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作者：
R. Mikkelsen;L. Reinlib;M. Donowitz;D. Zahniser
使用Ca2(+)敏感荧光染料fura-2的数字化视频增强荧光显微镜测量HT-29人结肠癌细胞中胞质游离Ca2+[(Ca2+]f)。 37 摄氏度时，单个细胞的 [Ca2+]f 范围在 50 至 150 nM 之间，平均值为 120 nM。将温度升高至 41 摄氏度持续 1 小时导致平均 [Ca2+]f 略有可逆下降 (10-20%)。在 44°C 下 1 小时，大多数（大于 80%）细胞表现出大于 200 nM 的 [Ca2+]f。这种热诱导的 [Ca2+]f 升高并非立即发生，而是在 30 分钟的滞后时间后开始。加热后在 37°C 下孵育 2-6 小时，在 44°C 下孵育 1 小时导致一些但不是所有细胞中基础 [Ca2+]f 的恢复。 37°C 后加热孵育后，细胞杀伤百分比与 [Ca2+]f 大于 200 nM 的细胞数量之间确定线性关系。加热期间将细胞外 [Ca2+] 控制在 0.1 至 10 mM 之间并不会改变热诱导的 [Ca2+]f 变化。在 10、1.0 和 0 [加上 1.0 mM 乙二醇双（β-氨基乙基醚）-N,N,N',N'-四乙酸]mM 细胞外 Ca2+ 下培养的细胞，在 37°C 或 44°C 下的存活率没有观察到显着差异。 Ca2+ 通道阻滞剂维拉帕米和硝苯地平不能保护细胞免受热处理。这些结果表明，热诱导的细胞内 Ca2+ 稳态机制的不可逆变化可能是热细胞毒性的关键因素。
Digitized video-intensified fluorescence microscopy with the Ca2(+)-sensitive fluorescent dye fura-2 was used to measure cytosolic free Ca2+ [( Ca2+]f) in HT-29 human colon cancer cells. At 37 degrees C, the [Ca2+]f of individual cells ranged between 50 and 150 nM, with a mean of 120 nM. Raising the temperature to 41 degrees C for 1 h resulted in a slight reversible decrease (10-20%) in the mean [Ca2+]f. At 44 degrees C for 1 h, most (greater than 80%) cells exhibited a [Ca2+]f greater than 200 nM. This heat-induced rise in [Ca2+]f was not immediate but commenced after a lag time of 30 min. Postincubation at 37 degrees C for 2-6 h after heating, for 1 h at 44 degrees C resulted in a recovery of the basal [Ca2+]f in some but not all cells. A linear relationship was determined between percentage of cell killing and the number of cells with [Ca2+]f of greater than 200 nM after 37 degrees C post-heating incubation. Manipulation of extracellular [Ca2+] between 0.1 and 10 mM during heating did not modify the heat-induced changes in [Ca2+]f. No significant differences in survival at 37 degrees C or 44 degrees C were observed with cells incubated at 10, 1.0, and 0 [plus 1.0 mM ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] mM extracellular Ca2+. The Ca2+ channel blockers verapamil and nifedipine did not protect cells from heat treatment. These results suggest that irreversible heat-induced changes in intracellular Ca2+ homeostasis mechanisms may be a critical factor in heat cytotoxicity.