Institute of Parasitology, Macdonald Campus of McGill University, 21,111 Lakeshore Road, Ste-Anne de Bellevue, QC, H9X 3V9 Canada.
J Fish Biol. 2009 Dec;75(10):2642-56. doi: 10.1111/j.1095-8649.2009.02457.x.
This study assessed the histological changes in the epidermis of guppies Poecilia reticulata induced by waterborne zinc (Zn). Laboratory-reared P. reticulata fry were maintained individually in separate vessels containing artificial water (8 microg l(-1) Zn) to which 0, 15, 30, 60 or 120 microg l(-1) Zn was added. Their epidermal response to Zn was monitored regularly over 4 weeks. Compared with controls, mucus was rapidly released and mucous cell numbers decreased at all concentrations. Thereafter mucous release, epidermal thickness, numbers and size of mucous cells fluctuated at a rate that varied with Zn concentration, but fluctuations declined after day 18. Results clearly highlight the dynamic nature of the epidermal response to sublethal concentrations of waterborne Zn. In general, low concentrations of Zn induced a rapid response with reduced numbers and size of mucous cells and shift in mucin composition, and a subsequent thickening of the epidermis. Epidermal thickness and mucous cell area fluctuated over time but were normal after a month of exposure to low Zn concentrations. The number of mucous cells, however, remained low. Virtually all mucous cells from fish maintained in 15 and 60 microg l(-1) Zn contained acidic mucins throughout the month, whereas fish maintained at 30 microg l(-1) Zn responded by production of neutral mucins during the first 12 days followed by a mixture of neutral and acidic mucins. At 120 microg l(-1) Zn, the most dramatic effects were the gradual but sustained decrease in numbers and area of mucous cells, and the shift to acidic mucins in these cells. Thus, as concentration of Zn increased, the epidermal responses indicated a disturbed host response (dramatic decline in mucous cell numbers, with mixed composition of mucins), which may have been less effective in preventing Zn uptake across the epithelium.
本研究评估了斑马鱼表皮的组织学变化，这些斑马鱼是由水传播的锌（Zn）诱导的。实验室饲养的斑马鱼幼鱼单独饲养在含有人工水（8 微克/升 Zn）的单独容器中，向其中添加 0、15、30、60 或 120 微克/升的 Zn。他们的表皮对 Zn 的反应在 4 周内定期监测。与对照组相比，所有浓度下的黏液都迅速释放，黏液细胞数量减少。此后，黏液释放、表皮厚度、黏液细胞数量和大小的波动速率随 Zn 浓度的变化而变化，但波动在第 18 天后下降。结果清楚地强调了表皮对亚致死浓度水传播 Zn 的动态反应。一般来说，低浓度的 Zn 诱导了快速反应，导致黏液细胞数量和大小减少，粘蛋白组成发生变化，随后表皮变厚。表皮厚度和黏液细胞面积随时间波动，但在低 Zn 浓度暴露一个月后恢复正常。然而，黏液细胞数量仍然很低。在 15 和 60 微克/升 Zn 中饲养的鱼类的几乎所有黏液细胞在整个月内都含有酸性粘蛋白，而在 30 微克/升 Zn 中饲养的鱼类在最初的 12 天内通过产生中性粘蛋白做出反应，然后是中性和酸性粘蛋白的混合物。在 120 微克/升 Zn 下，最显著的影响是黏液细胞数量和面积逐渐但持续减少，以及这些细胞中粘蛋白向酸性粘蛋白的转变。因此，随着 Zn 浓度的增加，表皮反应表明宿主反应受到干扰（黏液细胞数量急剧下降，粘蛋白组成混合），这可能使上皮细胞对 Zn 的摄取的预防效果降低。
