Juntao Chen,1,2,* Chunjiao Lu,2,* Wenjie Xie,1,2 Xiaoqian Cao,1 Jiannan Zhang,1 Juanjuan Luo,2 Juan Li1 

1Key Laboratory of Bioresources and Eco-Environment of Ministry of Education, College of Life Science, Sichuan University, Chengdu, People’s Republic of China; 2Engineering Research Center of Key Technique for Biotherapy of Guangdong Province, Shantou University Medical College, Shantou, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Juan Li, Key Laboratory of Bioresources and Eco-environment of Ministry of Education, College of Life Science, Sichuan University, No. 24 South Section 1, Yihuan Road, Chengdu, 610065, People’s Republic of China, Email lijuanscuhk@163.com Juanjuan Luo, Engineering Research Center of Key Technique for Biotherapy of Guangdong Province, Shantou University Medical College, 22 Xinling Road, Shantou, 515041, People’s Republic of China, Email 15jjluo1@stu.edu.cn

Introduction: The proliferation of nanoplastics (NPs) has emerged as a significant environmental concern due to their extensive use, raising concerns about potential adverse effects on human health. However, the exact impacts of NPs on the early development of hematopoietic organs remain poorly understood.
Methods: This investigation utilized fluorescence microscopy to observe the effects of various NP concentrations on the caudal vein plexus (CVP) development in zebrafish embryos. Subsequent RNA sequencing (RNA-seq) identified genes related to CVP deformities and hematopoietic stem/progenitor cells (HSPCs) in zebrafish embryos exposed to NPs. Additionally, single cell RNA sequencing (scRNA-seq) analysis identified genes associated with the development of CVP and HSPCs. RT-qPCR assessed changes in expression of these genes in zebrafish embryos exposed to different NP concentrations.
Results: The impact of NPs on zebrafish embryos was investigated, revealing significant reductions in survival and hatching rates and decreases in body length alongside increased heart rates. Exposure to NPs at 8 mg/L severely impaired zebrafish CVP development. RNA-seq revealed that NPs exposure altered the activity of oxidative enzymes, hydrolases, and the extracellular matrix in zebrafish embryos. Treatment with 10 μM NAC effectively rescued the CVP defects induced by NPs. Additionally, scRNA-seq identified genes associated with EC and HSPC development, and subsequent RT-qPCR validation confirmed significant expression changes in these genes.
Conclusion: The results of this study suggest that NPs induce oxidative stress in vascular ECs and HSPCs, which mediates CVP damage and impairs hematopoiesis in zebrafish embryos.

Keywords: nanoplastics, caudal vein plexus, oxidative stress, endothelial cells, hematopoietic stem/progenitor cells, zebrafish, single cell RNA sequencing