Effects of Photoaged Polyethylene Microplastics on Cardiac Injury and Fibrosis-like Remodeling in Zebrafish

Q: What are the key findings of this study?

Photoaged polyethylene microplastics (25 mg/L) increased zebrafish myocardial Sirius Red collagen-positive area to 47.60% vs 22.38% in controls (p<0.0001) at 28 days.

Q: What is the clinical evidence from this study?

Population: Microplastic-induced cardiac injury and fibrosis-like remodeling in an animal model (n=900). Intervention: Photoaged and pristine polyethylene microplastics (PE-MPs, nominal diameter ~50 μm) vs. Unexposed E3 medium control group (Ctrl) and pristine unaged PE-MPs (U-MPs) at matched concentrations. Primary outcome: Myocardial collagen-positive area percentage via Sirius Red staining at day 28 (comparing 25 mg/L photoaged PE-MPs vs control) (p=<0.0001).

Q: What does this research mean for the field?

Photoaged polyethylene microplastics induce cardiac oxidative injury, structural disorganization, and fibrosis-like remodeling in adult zebrafish, increasing myocardial collagen deposition to 47.60% compared to 22.38% in controls. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To compare the cardiotoxicity, oxidative stress responses, and fibrosis-like myocardial remodeling induced by pristine versus photoaged polyethylene microplastics in adult zebrafish.

Churan Sun; Feifei Yan; 张继东; Jing Zhang

doi:10.3390/toxics14100889

October 5, 2026ToxicsOpen Access

Effects of Photoaged Polyethylene Microplastics on Cardiac Injury and Fibrosis-like Remodeling in Zebrafish

View Full Paper

Ask AI

Bookmark

Share

Key result

Photoaged polyethylene microplastics increase myocardial collagen deposition by ~25 percentage points in zebrafish.

P<0.0001
n=900

Why the study?

Environmental ultraviolet irradiation causes photoaging of polyethylene microplastics, which may alter their cardiotoxicity, but the effects on cardiac injury and remodeling are not well understood.

Does environmental UV photoaging of polyethylene microplastics enhance cardiac oxidative injury and fibrosis-like remodeling in adult male zebrafish compared to pristine microplastics?

Key Points

To compare the cardiotoxicity, oxidative stress responses, and fibrosis-like myocardial remodeling induced by pristine versus photoaged polyethylene microplastics in adult zebrafish.
Subjected polyethylene microplastics (PE-MPs) to 28 days of ultraviolet photoaging, characterizing physicochemical changes via scanning electron microscopy and Fourier-transform infrared spectroscopy.
Exposed adult zebrafish (n=3 replicates of 10 fish per group) for 28 days to pristine or photoaged PE-MPs at 5 mg/L and 25 mg/L following a 96-hour acute toxicity assessment (LC50: 787.1 mg/L).
Evaluated growth phenotypes, cardiac oxidative stress markers (T-SOD, CAT, MDA), myocardial histopathology, and collagen deposition using Sirius Red and Masson trichrome staining.
Photoaging increased PE-MP surface cracking, porosity, and oxidation, raising the apparent carbonyl index by 148.4% and the hydroxyl index by 42.2%.
By day 28, cardiac T-SOD activity remained suppressed by 68.5% to 78.8% across exposure groups versus controls (all p<0.001) and was 21.9% lower in the high-concentration photoaged group than the matched pristine group (p=0.0047).
Sirius Red staining showed mean collagen-positive area ratios rose from 22.38% in controls to 47.60% in the high-concentration photoaged group, representing a 97.8% increase compared with the matched pristine group (p<0.0001).

Structured PICO

Does environmental UV photoaging of polyethylene microplastics enhance cardiac oxidative injury and fibrosis-like remodeling in adult male zebrafish compared to pristine microplastics?

P

Population

900 healthy six-month-old male AB strain zebrafish (distributed across 15 tanks, n=3 independent biological replicate tanks per group across 5 groups) exposed to pristine or photoaged polyethylene microplastics for 28 days.

I

Intervention

Pristine (unaged, U-MPs) or UV-photoaged polyethylene microplastics (Aged-MPs; nominal diameter ~50 μm, photoaged under UVB 313 nm for 28 days) at low (5 mg/L) and high (25 mg/L) concentrations in E3 medium renewed daily for 28 days.

C

Comparator

Unexposed control group maintained in continuously aerated E3 medium under identical temperature, photoperiod, and handling conditions, as well as parallel comparison between pristine and photoaged polyethylene microplastics at matched concentrations.

O

Outcome

Cardiotoxicity evaluated via organismal growth phenotypes (body length and body weight at day 28), cardiac oxidative stress (total superoxide dismutase [T-SOD] and catalase [CAT] activities, malondialdehyde [MDA] content at days 7 and 28), myocardial histopathology (HE staining at day 28), myocardial collagen deposition (Sirius Red and Masson trichrome staining at day 28), and cardiac gene expression (il1b, acta2, ccn2a, col1a1a, mmp9 via qPCR at days 7 and 28).surrogate

Main Result

Absolute Event Rate: 47.6% vs 22.38%

p-value: p=<0.0001

Both pristine and photoaged polyethylene microplastics induce cardiac oxidative stress, structural disorganization, and fibrosis-like remodeling in adult zebrafish, with environmental UV photoaging selectively exacerbating certain cardiotoxic endpoints.

Limitations

Particle size distribution, specific surface area, zeta potential, contact angle, aggregation or sedimentation kinetics, additives, and soluble photooxidation products were not measured.
UV irradiance was based on a calculated nominal value (10 mW/cm2) rather than an independent measurement at the sample plane.
No control corresponding to the soluble fraction or leachate from photoaged microplastics was included.
Reactive oxygen species (ROS) levels were not measured directly and no antioxidant intervention was performed to establish causality.
CAT activity and MDA content were only measured on day 7, while only T-SOD was measured on both days 7 and 28 due to limited cardiac tissue and resource constraints.
Small statistical sample size of n = 3 independent exposure tanks per group.
HE histopathological evaluation was strictly descriptive without a semiquantitative severity scoring system.
Laboratory-accelerated UV aging was not designed to quantitatively reproduce environmental aging under natural sunlight.
Exposure concentrations (5 and 25 mg/L) were selected to establish an experimental gradient for hazard assessment and are not representative of typical exposure levels in natural aquatic environments.
Because SEM accelerating voltages differed between groups, SEM images were used only for qualitative comparison without quantitative evaluation of parameters like crack depth.
The study did not infer particle size distribution, specific surface area, zeta potential, surface charge, wettability, aggregation, or sedimentation behavior.
No semiquantitative histopathological severity scoring system was established a priori for HE staining, so findings were treated solely as qualitative.

Ask about this paper

Answers are grounded in this paper and cite their sources.

Implication

Photoaged microplastics may exacerbate zebrafish myocardial fibrosis; hypothesis-generating for human exposures and should not change practice.

Abstract

Polyethylene microplastics (PE-MPs) undergo photoaging under environmental ultraviolet irradiation, which may alter their surface morphology, chemical properties, and biological toxicity. This study used adult zebrafish to compare cardiac injury induced by pristine and photoaged PE-MPs. Changes in particle physicochemical properties were characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy. Cardiotoxicity was evaluated using organismal phenotypes, cardiac oxidative stress, histopathology, collagen deposition, and related gene expression. Photoaging increased surface roughness, pores, cracks, and oxidation, confirming marked changes in particle structure and chemistry. High-concentration PE-MP exposure inhibited growth. All exposure groups showed decreased cardiac antioxidant enzyme activities and increased lipid peroxidation, with more pronounced oxidative injury in the high-concentration photoaged group. This group also exhibited abnormal myocardial structural disorganization, inflammatory cell infiltration, and fibrosis-like changes. Genes involved in inflammation, profibrotic transcription, and extracellular matrix remodeling were also altered. Overall, PE-MPs induced cardiac oxidative injury, structural abnormalities, and changes associated with collagen remodeling in adult zebrafish, with the combined findings being consistent with fibrosis-like remodeling. Photoaging selectively enhanced some cardiac endpoints, but this effect was not consistently observed across all measured indicators. These findings indicate that environmental aging can modify the cardiotoxicity of PE-MPs and provide experimental evidence for assessing the potential cardiovascular hazards and identifying aging-related changes in toxicity of aged microplastics.

Discussion

No takes yet. Share an insight, caveat, or question.

Cite This Study

Sun et al. (2026) studied Microplastic-induced cardiac injury and fibrosis-like remodeling in an animal model (n=900). Photoaged and pristine polyethylene microplastics (PE-MPs, nominal diameter ~50 μm) vs. Unexposed E3 medium control group (Ctrl) and pristine unaged PE-MPs (U-MPs) at matched concentrations was evaluated on Myocardial collagen-positive area percentage via Sirius Red staining at day 28 (comparing 25 mg/L photoaged PE-MPs vs control) (p=<0.0001). Photoaged polyethylene microplastics (25 mg/L) increased zebrafish myocardial Sirius Red collagen-positive area to 47.60% vs 22.38% in controls (p<0.0001) at 28 days.

synapsesocial.com/papers/6ac5e0d1b2dceb1c429fb334 https://doi.org/10.3390/toxics14100889

View Full Paper

Ask AI

Bookmark

Share

Effects of Photoaged Polyethylene Microplastics on Cardiac Injury and Fibrosis-like Remodeling in Zebrafish

Key Points

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Effects of Photoaged Polyethylene Microplastics on Cardiac Injury and Fibrosis-like Remodeling in Zebrafish

Key Points

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Keep reading

Keep reading