聚丙烯微塑料和磺胺脒复合暴露对青海湖裸鲤生长、生理生化特征的影响

COMPOSITE EXPOSURE OF POLYPROPYLENE MICROPLASTICS AND SULFAMIDINE ON THE GROWTH, PHYSIOLOGY, AND BIOCHEMISTRY CHARACTERISTICS IN GYMNOCYPRIS PRZEWALSKII

  • 摘要: 为探究青海湖中检出的聚丙烯微塑料(Polypropylene microplastics, PP-MPs)及磺胺脒抗生素(Sulfaguanidine, SGD)对青海湖裸鲤的的毒性效应, 研究以青海湖裸鲤为实验对象, 设置对照组(C)、3个单独暴露组(1 g/L SGD、1 mg/L PP-MPs和 5 mg/L PP-MPs)和2个复合暴露组(1 mg/L PP-MPs+1 g/L SGD和 5 mg/L PP-MPs+1 g/L SGD)进行28d暴露处理, 利用目检法测定PP-MPs在各组织的富集特征, 并通过组织切片HE染色、肠道消化酶和肝脏氧化酶活性的测定评估其毒性效应。生长指标分析结果表明PP-MPs和SGD单一和复合暴露对青海湖裸鲤体长体重未产生影响, 但在青海湖裸鲤鳃、肠道、肝脏和脑组织中都能检测到PP-MPs, 且在鳃和肠道中的浓度较高, 并随暴露时间增加而增加。切片结果进一步表明随着PP-MPs的积累, 高浓度微塑料暴露组肠道绒毛长度显著低于对照组, 绒隐比降低, 且在肝脏组织中细胞质减少、细胞核皱缩现象更明显, 并出现炎症细胞浸润。酶活性测定结果表明: 单一暴露与复合暴露对淀粉酶和脂肪酶的活性产生显著差异影响, 并呈现浓度依赖性; 肝脏组织中的氧化酶在相同浓度的PP-MPs处理下, 复合暴露组的过氧化氢酶及超氧化物歧化酶活性均高于单一暴露组(P<0.05)。综上所述, PP-MPs的单一和复合暴露均使微塑料在青海湖裸鲤多组织中富集, 并引起肠道和肝脏组织损坏和氧化应激反应, 且随着微塑料浓度增加以及与抗生素的复合暴露而加剧。研究为探讨微塑料与其他污染物共存对青海湖裸鲤的毒理危害提供理论依据, 对评估青海湖生态系统的潜在风险具有重要意义。

     

    Abstract: Polypropylene microplastics (PP-MPs) and sulfaguanidine (SGD) have been detected in the water, sediment, and aquatic organisms of Qinghai Lake. In order to investigate the toxic effects of combined exposure to PP-MPs and SGD on the G. przewalskii, we divided the fish into six groups: a control group (C), three singly exposed groups (1 g/L SGD, 1 mg/L PP-MPs, and 5 mg/L PP-MPs, labeled as S, PL, and PH), and two combined exposed groups (1 mg/L PP-MPs+1g/L SGD and 5 mg/L PP-MPs+1 g/L SGD, labeled as SPL and SPH) for a 28d exposure treatment. The enrichment characteristics of PP-MPs in different tissues were determined using tissue acid digestion, and the toxic effects were evaluated through hematoxylin-eosin staining, as well as measurements of intestinal digestive enzyme and liver oxidative enzyme activities. The growth index analysis showed that single and combined exposure to PP-MPs and SGD had little effect on the body length and weight of the G. przewalskii. However, PP-MPs were detected in the gills, intestines, liver, and brain tissues of the exposed groups, with higher concentrations in the gills and intestines increasing with exposure time. Histological analysis revealed that as PP-MPs accumulated, the length of intestinal villi and the villus height to crypt depth ratio decreased. In the liver tissue, cell nuclear shrinkage and disintegration, reduced cytoplasm, and infiltration of inflammatory cells were observed. The damage was more severe in the PH group compared to the PL group and was more pronounced in the combined exposure group than that in the single exposure group. Enzyme activity measurements indicated an increasing trend in intestinal lipase activity in the exposed groups compared to the control group, while amylase activity decreased, and there was no significant change in pancreatic enzyme activity. Hydrogen peroxide enzyme activity in liver tissue significantly increased, while superoxide dismutase activity was significantly higher in the S group and the SPL and SPH combined groups. In summary, both single and combined exposure to PP-MPs and SGD resulted in the enrichment of microplastics in various tissues of the G. przewalskii, causing damage to intestinal and liver tissues and oxidative stress reactions. The severity of the damage increased with higher concentrations of microplastics, and combined exposure was more severe than single exposure. This study provides a theoretical basis for exploring the toxicological harm of coexisting microplastics and other pollutants on G. przewalskii and is of great significance for assessing potential risks to the Qinghai Lake ecosystem.

     

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