基于因子分析的Cd^(2+)胁迫下赤子爱胜蚓氧化应激响应

Oxidative response of earthworm Eisenia fetida to Cd^(2+) stress based on factor analysis

蚯蚓受到胁迫时,体内立即产生氧化应激反应,从而使得蚯蚓成为一种灵敏的指示性生物而被广泛应用于各类污染物的监测指示中。由于与蚯蚓氧化应激反应相关的因素众多,找出污染物胁迫过程中重点监测的指标是污染监测警示过程的现实需求。因子分析是在损失较少信息的前提下,将原来多个变量转化为少数的几个综合指标的一种统计方法。本研究运用该方法对重金属胁迫下蚯蚓氧化应激相关指标进行筛选和分析。试验在人工土壤条件下进行,分短期和长期试验2组,前者试验周期10 d,每天取出1条蚯蚓,后者试验周期为30 d,每10天取出1条蚯蚓。每组均设定0、50、100、125、250和500 mg·kg-1的Cd^(2+)浓度梯度溶液,选择蚯蚓环带后部进行体内SOD、POD、GPX、GST、MDA、CAT、VE和ACh E的测定。结果表明:短期试验组蚯蚓受到Cd^(2+)胁迫1~3天时,蚯蚓体内氧化应激的主要指标是CAT,4~5天时是MDA,6~7天时是POD,在第8天时是GST和GPX,在9~10天时是CAT,而在长期试验中,蚯蚓体内氧化应激的主要指标则是GPX。

When earthworms are exposed to pollutants, their antioxidant system will have responses immediately. Consequently earthworms are widely used to monitor various pollutants as sensitive bioindicator organisms. However, there are a large number of indices associated with the oxidative stress response. Finding out the key monitoring indices in the stress process becomes a practical demand of pollution monitoring and warning process. Factor analysis approach is a statistical method that uses a few factors to replace many original factors. This paper is aimed at analyzing and sorting factors related to Cd2＋ on the earthworm Eisenia fetida under oxidative stress. Our experiment was divided into two groups： shortterm test and longterm test. The former one was for ten days, taking out an earthworm every day for analysis; The latter test lasted for 30 days, taking out an earthworm every ten days. The Cd2＋ concentration was set at 0, 50, 100, 125, 250 and 500 mg·kg-1. Postclitellum segments of earthworms were chosen to determine SOD, POD, GPX, GST, CAT, VE, MDA and AChE. The results showed that in the shortterm group, the main bioindicator associated with oxidative stress reaction was CAT at the exposure time of 1-3 days, MDA at 4-5 days, POD at 6-7 days, and GST and GPX at 8th day, CAT at days 9-10. With the longterm test, GPX was the main bioindicator associated with oxidative stress reaction.