Comparison of reproductive toxicity between pristine and aged polylactic acid microplastics in Caenorhabditis elegans

J Hazard Mater. 2024 Mar 15:466:133545. doi: 10.1016/j.jhazmat.2024.133545. Epub 2024 Jan 17.

Abstract

Caenorhabditis elegans was employed as model to compare reproductive toxicity between pristine and aged polylactic acid microplastics (PLA-MPs). Aged PLA-MPs induced by UV irradiation showed degradation reflected by decrease in size and alteration in morphological surface. Aged PLA-MPs also exhibited some certain changes of chemical properties compared to pristine PLA-MP. Compared with pristine PLA-MPs, more severe toxicity on reproductive capacity and gonad development was detected in 1-100 μg/L aged PLA-MPs. Meanwhile, aged PLA-MPs caused more severe enhancement in germline apoptosis and alterations in expressions of ced-9, ced-4, ced-3, and egl-1 governing cell apoptosis. In addition, aged PLA-MPs resulted in more severe increase in expression of DNA damage related genes (cep-1, mrt-2, hus-1, and clk-2) compared to pristine PLA-MPs, and the alterations in expression of ced-9, ced-4, ced-3, and egl-1 in pristine and aged PLA-MPs could be reversed by RNAi of cep-1, mrt-2, hus-1, and clk-2. Besides this, enhanced germline apoptosis in pristine and aged PLA-MPs exposed animals was also suppressed by RNAi of cep-1, mrt-2, hus-1, and clk-2. Therefore, our results suggested the more severe exposure risk of aged PLA-MPs than pristine PLA-MPs in causing reproductive toxicity, which was associated with the changed physicochemical properties and DNA damage induced germline apoptosis.

Keywords: Aged microplastics; C. elegans; Polylactic acid; Reproductive toxicity.

MeSH terms

  • Animals
  • Caenorhabditis elegans* / genetics
  • Caenorhabditis elegans* / metabolism
  • Microplastics* / metabolism
  • Plastics / metabolism
  • Polyesters

Substances

  • Microplastics
  • Plastics
  • poly(lactide)
  • Polyesters