荧光聚苯乙烯微球对蝌蚪应激水平和免疫功能的影响

Effects of fluorescent polystyrene microsphere on stress level and immune function in the tadpoles of Pelophylax nigromaculatus

为探究纳米塑料对黑斑侧褶蛙(Pelophylax nigromaculatus)37期蝌蚪健康状态的影响,将其暴露于50 nm粒径低、中和高浓度荧光聚苯乙烯微球溶液(fluorescent polystyrene microsphere solution, FPMS)7 d(7 d时),之后分别移至清水中饲养7 d(14 d时)或14 d(21 d时),以清水组为对照组,测定了每一取样时间点不同浓度组、同一浓度组不同取样时间点的体重与体全长的比值(重长比)、嗜中性粒细胞与淋巴细胞的比值(N/L)和对植物血凝素(phytohemagglutinin, PHA-P)的反应差异。结果表明:重长比只在14 d时清水组显著低于其他浓度组;N/L只在21 d时清水组低于其他浓度组,低、中和高浓度组都从7 d时至21 d时显著增加;7 d时各浓度组蝌蚪对PHA-P的最大反应值出现于注射后3 h或4 h, 14 d时前移至2 h或3 h, 21 d时又恢复至3 h或4 h,只有21 d时高浓度组高于低浓度组和中浓度组;FPMs暴露和初次清除对黑斑侧褶蛙蝌蚪的生长发育有明显的促进作用,但随处理时间延长而消失,同时蝌蚪对外界刺激的应激反应能力显著增强,但不以受抑制的免疫功能作为代价。

To explore the effects of nano-scale microplastics on the health status of Gosner stage 37 tadpoles of Dark-spotted frogs,Pelophylax nigromaculatus,the tadpoles were exposed to low,moderate,or high concentration of fluorescent polystyrene microspheres(FPMs,50 nm in diameter)solution for 7 days(day 7),then they were transferred to clear water and housed for 7 days(day 14)or 14 days(day 21).Clear water group was used as the control.The variations of the ratio of body mass to total body length,the ratio of neutrophils to lymphocytes(N/L ratio),and the responsiveness to phytohemagglutinin(PHA-P)were measured in multiple sampling time points for each group.On day 14,the ratio of body mass to total body length was significantly lower in control than that of any other FPMs groups.On day 21,the N/L ratio was significantly lower in control than that of any other FPMs groups,which was greatly increased from day 7 to day 21 for low,moderate or high concentration groups.The peak of the responsiveness to PHA-P for different concentration groups of FPMs on day 7 was observed after injection 3 h or 4 h,and occurred forwards after injection 2 h or 3 h on day 14,then gradually returned to that after injection 3 h or 4 h on day 21.On day 21,the peak of the responsiveness to PHA-P in high concentration group was higher than that of low and moderate concentration groups.Exposure and primary clearance of FPMs significantly promoted the growth and development of tadpoles of Dark-spotted pond frog,but such effect disappeared with increasing duration of treatments.Meanwhile,the stress level of the tadpoles responding to external stimuli was significantly increased,but not at the expense of suppressed immune function.