Anderson R S, Brubacher L L, Calvo L M, Burreson E M, Unger M A
Chesapeake Biological Laboratory, University of Maryland, Solomons 20688, USA.
Environ Res. 1997;74(1):84-90. doi: 10.1006/enrs.1997.3751.
Mollusks depend chiefly on hemocyte-mediated cytotoxic mechanisms such as reactive oxygen species (ROS) to defend against pathogenic microorganisms. The effect of in vitro tributyltin chloride (TBT) exposure on ROS generation by oyster (Crassostrea virginica) blood phagocytes is quantified in this study. Luminol-augmented chemiluminescence (LCL) was used to measure ROS activity of resting and zymosan-stimulated cells after 1 or 20 hr TBT exposure. LCL is thought to measure primarily the activity of the myeloperoxidase/hydrogen peroxide/ halide antimicrobial pathway. Hemocytes in TBT-free medium (controls) produced low level LCL, which was markedly stimulated by the addition of zymosan particles. Both resting and zymosan-stimulated LCL values were significantly inhibited by > or = 80 ppb TBT after either 1 or 20 hr of exposure. Exposure to < or = 2 ppb TBT concentrations for 20 hr produced slightly enhanced LCL activity, suggesting a hormesis-like effect. Partial reversibility of TBT suppression of LCL took place when previously exposed cells were put in TBT-free medium. The TBT concentrations used in these studies were not cytolethal in vitro and were considerably less than oyster tissue levels recorded after chronic, sublethal in vitro exposures. The data suggest that the common aquatic contaminant TBT can interact rapidly with C. virginica hemocytes to produce a partially reversible immunotoxicological lesion. Xenobiotic-induced suppression of ROS production by hemocytes may increase host susceptibility to infectious diseases.
软体动物主要依靠血细胞介导的细胞毒性机制，如活性氧（ROS）来抵御病原微生物。本研究定量了体外暴露于三丁基氯化锡（TBT）对牡蛎（弗吉尼亚巨蛎）血液吞噬细胞产生ROS的影响。采用鲁米诺增强化学发光法（LCL）测定TBT暴露1小时或20小时后静息细胞和经酵母聚糖刺激的细胞的ROS活性。LCL主要被认为是测量髓过氧化物酶/过氧化氢/卤化物抗菌途径的活性。在不含TBT的培养基（对照）中的血细胞产生低水平的LCL，添加酵母聚糖颗粒后LCL明显受到刺激。暴露1小时或20小时后，≥80 ppb的TBT显著抑制了静息细胞和经酵母聚糖刺激的细胞的LCL值。暴露于≤2 ppb的TBT浓度20小时会使LCL活性略有增强，表明存在类兴奋效应。当先前暴露的细胞置于不含TBT的培养基中时，TBT对LCL的抑制作用部分可逆。这些研究中使用的TBT浓度在体外没有细胞毒性，并且远低于慢性亚致死体外暴露后记录的牡蛎组织水平。数据表明，常见的水生污染物TBT可迅速与弗吉尼亚巨蛎血细胞相互作用，产生部分可逆的免疫毒理学损伤。异源生物诱导的血细胞ROS产生抑制可能会增加宿主对传染病的易感性。
