At present, beneficial effects of melanin and harmful effects of barium have been reported. However, little is known about the adsorption of barium, and even less is known about the biological significance of adsorption of barium by melanin. In this study, we showed that there was a strong correlation between the digitalized level of skin pigmentation and barium level in murine skin compared to the correlations between skin pigmentation level and levels of homologous elements of barium (magnesium, calcium and strontium). The concentration of subcutaneously injected barium in skin with a high level of pigmentation was higher than that in skin with a low level of pigmentation. Our cell-free experiment using the Langmuir isotherm for adsorption of barium in synthetic melanin also provided direct evidence of adsorption of barium by melanin. We then investigated the biological significance of melanin-mediated barium adsorption. We found barium-mediated increase in transforming activity in pigmented melanocytes (melan-a) but not in unpigmented melanocytes (melan-c) after confirming that the barium level in melan-a melanocytes was 3.4-fold higher than that in melan-c melanocytes after culture of 5 μM barium for 24 h. Taken together, our results not only indicate adsorption of barium by melanin in mice, cells and cell-free systems but also suggest a disadvantageous effect of adsorption of barium by melanin on transforming activity in cultured cells.

目前，已经报道了黑色素的有益作用和钡的有害作用。然而，对钡的吸附知之甚少，而黑色素对钡的吸附的生物学意义则知之甚少。在这项研究中，我们表明，与皮肤色素沉着水平和钡同源元素（镁，钙和锶）水平之间的相关性相比，鼠皮中皮肤色素沉着的数字化水平与钡水平之间存在很强的相关性。色素沉着程度高的皮肤中皮下注射钡的浓度高于色素沉着程度低的皮肤中的钡浓度。我们使用Langmuir等温线吸附合成黑色素中钡的无细胞实验也提供了黑色素吸附钡的直接证据。然后，我们研究了黑色素介导的钡吸附的生物学意义。在确认黑色素-a黑色素细胞的钡含量比黑色素-c黑色素细胞高3.4倍后，我们发现钡介导的有色黑色素细胞（melan-a）的转化活性增加，但未染色的黑色素细胞（melan-c）却没有。在5μM钡培养24小时后。两者合计，我们的结果不仅表明黑色素在小鼠，细胞和无细胞系统中对钡的吸附，而且还表明黑色素对钡的吸附对培养细胞的转化活性具有不利影响。在确认黑色素-a黑色素细胞的钡含量比黑色素-c黑色素细胞高3.4倍后，我们发现钡介导的有色黑色素细胞（melan-a）的转化活性增加，但未染色的黑色素细胞（melan-c）却没有。在5μM钡培养24小时后。两者合计，我们的结果不仅表明黑色素在小鼠，细胞和无细胞系统中对钡的吸附，而且还表明黑色素对钡的吸附对培养细胞的转化活性具有不利影响。在确认黑色素-a黑色素细胞的钡含量比黑色素-c黑色素细胞高3.4倍后，我们发现钡介导的有色黑色素细胞（melan-a）的转化活性增加，但未染色的黑色素细胞（melan-c）却没有。培养5μM钡24小时后。两者合计，我们的结果不仅表明黑色素在小鼠，细胞和无细胞系统中对钡的吸附，而且还表明黑色素对钡的吸附对培养细胞的转化活性具有不利影响。