Short-term exposure to polymethylmethacrylate nanoplastics alters muscle antioxidant response, development and growth in Sparus aurata. (November 2021) - Balasch, J.C.
Abstract: Polymethylmethacrylate (PMMA) plastic fragments have been found abundant in the environment, but the knowledge regarding its effects on the physiology of aquatic animals is still poorly studied. Here the short-term (96 h) effects of waterborne exposure to PMMA nanoplastics (PMMA-NPs) on the muscle of gilthead sea bream ( Sparus aurata ) fingerlings was evaluated at a concentration range that includes 0.001 up to 10 mg/L. The expression of key transcripts related to cell stress, tissue repair, immune response, antioxidant status and muscle development, together with several biochemical endpoints and metabolic parameters. Results indicate that exposure to PMMA-NPs elicit mildly antioxidant responses, enhanced the acetylcholinesterase (AChE) activity, and inhibited key regulators of muscle development (growth hormone receptors ghr-1/ghr-2 and myostatin, mstn-1 transcripts). However, no effects on pro-inflammatory cytokines (interleukin 1β, il1β and tumor necrosis factor α, tnfα ) expression nor on the levels of energetic substrates (glucose, triglycerides and cholesterol) were found. Highlights: Short-term (96 h) exposure to PMMA-NPs induces oxidative stress in S. aurata muscle. No pro-inflammatory responses or metabolic imbalances were observed. As a response to PMMA-NPs exposure, myostatin transcripts were inhibited. Myogenesis, however, does not seem to be extensively compromised. PMMA-NPs may induce mild short-term changes in muscle development and growth.