Brousseau P, Pellerin J, Morin Y, Cyr D, Blakley B, Boermans H, Fournier M
INRS-Institut Armand-Frappier, Santé Humaine, Pointe-Claire, Québec, Canada.
Toxicology. 2000 Jan 3;142(2):145-56. doi: 10.1016/s0300-483x(99)00165-1.
The effectiveness of toxicology biomonitoring programs could be improved by the addition of sensitive biomarkers. In this study the cell viability and sensitivity of phagocytic function of phagocytes from bivalves (Mya arenaria) to selected heavy metals were measured by flow cytometry, a novel approach. Hemocytes (phagocytes) collected from bivalves by puncture of the posterior adductor muscle were incubated in vitro for 18 h in hemolymph containing 10(-9)-10(-3)M of cadmium chloride, zinc chloride, mercuric chloride, methylmercury chloride or silver nitrate, before determining their capacity to phagocytose fluorescent latex beads by flow cytometry. Heterogeneity of the hemocyte cell population was determined by forward scatter (FSC) and side scatter (SSC) cytometric profile which showed two distinct cell populations. At low doses (10(-9), 10(-8) M), all the metal compounds studied stimulated phagocytic activity except silver nitrate. At higher levels of exposure (10(-6), 10(7) M), all metals caused a significant concentration-related decrease in hemocyte phagocytosis activity. From the concentration of each metal inducing 50% suppression (IC50) of the phagocytic activity, the immunotoxic potential of metals with respect to phagocytic function can be ranked in the following increasing order: ZnCl2 < CdCl2 < AgNO3 < HgCl2 < CH3HgCl. Parallel analysis of hemocyte viability showed that suppression of phagocytosis by heavy metals was not solely related to a decreased cell viability. These results reveal the high but different degree of sensitivity of the phagocytosis activity of bivalves with respect to heavy metals, as measured by flow cytometry, and demonstrate that flow cytometry is a potentially useful tool in ecotoxicological monitoring.
通过添加敏感的生物标志物可以提高毒理学生物监测项目的有效性。在本研究中，采用一种新方法——流式细胞术，测定了双壳贝类（砂海螂）吞噬细胞的细胞活力和对选定重金属的吞噬功能敏感性。通过穿刺后闭壳肌从双壳贝类收集血细胞（吞噬细胞），在含有10⁻⁹ - 10⁻³M氯化镉、氯化锌、氯化汞、甲基氯化汞或硝酸银的血淋巴中体外培养18小时，然后通过流式细胞术测定其吞噬荧光乳胶珠的能力。通过前向散射（FSC）和侧向散射（SSC）细胞计数图谱确定血细胞群体的异质性，该图谱显示出两个不同的细胞群体。在低剂量（10⁻⁹、10⁻⁸M）时，除硝酸银外，所有研究的金属化合物均刺激吞噬活性。在较高暴露水平（10⁻⁶、10⁻⁷M）时，所有金属均导致血细胞吞噬活性显著的浓度相关下降。根据每种金属诱导吞噬活性50%抑制（IC50）的浓度，金属对吞噬功能的免疫毒性潜力可按以下递增顺序排列：ZnCl₂ < CdCl₂ < AgNO₃ < HgCl₂ < CH₃HgCl。血细胞活力的平行分析表明，重金属对吞噬作用的抑制不仅仅与细胞活力降低有关。这些结果揭示了通过流式细胞术测定的双壳贝类吞噬活性对重金属具有高度但不同程度的敏感性，并证明流式细胞术是生态毒理学监测中一种潜在有用的工具。
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