Analysis of Pb2+ entry into cultured astroglia.
Analysis of Pb2+ entry into cultured astroglia.
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DOI：
10.1006/toxs.1998.2492
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发表时间：
1998-11
期刊：
影响因子：
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通讯作者：
Marie E. Legare;R. Barhoumi;E. Hébert;Gerald R. Bratton;Robert C. Burghardt;E. Tiffany‐Castiglioni
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文献类型：
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作者：
Marie E. Legare;R. Barhoumi;E. Hébert;Gerald R. Bratton;Robert C. Burghardt;E. Tiffany‐Castiglioni
星形胶质细胞作为一个假定的铅（Pb）汇在大脑中，因此，本研究探讨铅进入培养的大鼠星形胶质细胞利用Ca 2+荧光团indo-1作为工具，用于检测铅2+进入急性曝光。在无细胞体系中，用荧光分光光度法研究了Pb 2+与indo-1的相互作用。Pb ~（2+）/indo-1的发射光谱与Ca ~（2+）/indo-1的发射光谱有很大的不同，这是由于indo-1的荧光发射强度受到了抑制。接下来，我们建立了星形胶质细胞培养物中L型钙通道的存在，并证明了在无血清条件下和Bay-K 8644的应用下Pb积累增强。因为急性接触是毒理学相关性比反复低水平的曝光，然后我们研究了铅处理长达1周的文化铅的吸收。原子吸收光谱分析表明，铅积累伴随着总细胞[Ca]的增加。此外，观察到基础indo-1荧光水平的差异和对离子霉素的反应性的差异。离子霉素诱导未处理细胞的荧光比率增加，但铅处理1天的细胞对离子霉素没有反应。然而，处理3天和7天的细胞显示出对离子霉素的部分应答。TPEN用于评估Pb 2+与indo-1的相互作用，并且仅处理7天的细胞显示对TPEN的响应。因此，本研究的特点Pb 2+进入星形胶质细胞通过L-型钙通道，并提出了使用indo-1分析的Pb 2+摄取和随后的神经毒性事件在星形胶质细胞的可能性。
Astroglia serve as a presumptive lead (Pb) sink in the brain; therefore, this study examined Pb entry into cultured rat astroglia utilizing the Ca2+ fluorophore indo-1 as a tool for detecting Pb2+ entry during acute exposure. The interactions of Pb2+ with indo-1 were analyzed by fluorescence spectrophotometry in a cell-free system. The emission spectrum of Pb2+/indo-1 was substantially different from that of Ca2+/indo-1 due to suppression of indo-1 fluorescence emission intensity. Next, we established the presence of L-type Ca2+ channels in astroglial cultures and demonstrated that Pb accumulation is enhanced under serum-free conditions and by the application of Bay-K 8644. Because acute exposure is of less toxicologic relevance than repeated low-level exposure, we then examined Pb uptake in cultures treated for up to 1 week with Pb. AAS revealed that Pb accumulation was accompanied by an increase in total cellular [Ca]. In addition, differences in basal indo-1 fluorescence levels and differences in responsiveness to ionomycin were observed. Ionomycin induced an increase in the fluorescence ratio in untreated cells but cells treated for 1 day with Pb showed no response to ionomycin. However, cells treated for 3 and 7 days showed a partial response to ionomycin. TPEN was used to evaluate the interactions of Pb2+ with indo-1 and only cells treated for 7 days showed a response to TPEN. Thus, the present study characterizes Pb2+ entry into astroglia via L-type Ca2+ channels and presents the possibility of using indo-1 for analysis of Pb2+ uptake and the subsequent neurotoxic events in astroglia.