Chloroxylenol (PCMX) impairs visual system development and induces circadian rhythm disorders with sleep/wake behavioral abnormalities in zebrafish larvae, which can be ameliorated by melatonin intervention.
Exposure to PCMX at concentrations ≥0.4 mg/L caused ocular malformations and suppressed photoreceptor development in zebrafish larvae, while higher concentrations (≥1.2 mg/L) disrupted circadian clock gene expression and led to daytime hyperactivity and insomnia-like sleep fragmentation at night. Melatonin intervention effectively alleviated the sleep/wake behavioral deficits.
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Chloroxylenol (PCMX) impairs visual system development and induces circadian rhythm disorders with sleep/wake behavioral abnormalities in zebrafish larvae, which can be ameliorated by melatonin intervention. The current body of evidence comprises 1 study. EvidenceHub rates the overall confidence at 24/100 (low).
The Claim
Chloroxylenol (PCMX) impairs visual system development and induces circadian rhythm disorders with sleep/wake behavioral abnormalities in zebrafish larvae, which can be ameliorated by melatonin intervention.
This conclusion is most relevant to: Zebrafish (Danio rerio) larvae.
What the Research Shows
The conclusion draws on 1 linked study. Highlights from the cited literature:
- ▸Chloroxylenol impairs the visual system, induces visually-mediated behavioral abnormalities and circadian rhythm disorders in zebrafish (Danio rerio). (Comparative biochemistry and physiology. Toxicology & pharmacology : CBP, 2026) —
How It Works
The proposed biological pathway:
- ▸PCMX suppresses key genes regulating photoreceptor proliferation and differentiation
- ▸PCMX disrupts thyroid hormone signaling
- ▸This inhibits photoreceptor development and causes retinal pathology
- ▸Result: Impaired image-forming vision and visuomotor responses, plus disrupted circadian rhythms and sleep/wake behavior
Who Might Benefit
Evidence fit by population:
- ▸Zebrafish (Danio rerio) larvae
Recommended Dose
N/A
Limitations & Caveats
Important context when interpreting this evidence:
- ▸Study conducted in zebrafish larvae, not directly translatable to humans or mammals
- ▸Only acute exposure effects reported; chronic or low-dose effects not assessed
Frequently Asked Questions
What is PCMX and where is it found?▼
PCMX (p-Chloro-m-xylenol) is a broad-spectrum antimicrobial agent widely used in disinfectants and personal care products, frequently detected in aquatic environments.
Does melatonin help with PCMX-induced sleep problems?▼
Yes, the study found that melatonin intervention effectively alleviated the sleep/wake behavioral deficits caused by PCMX exposure in zebrafish larvae.
What concentrations of PCMX caused visual damage in this study?▼
Ocular malformations were observed at concentrations as low as 0.4 mg/L, with more severe visual impairments at 2 and 2.8 mg/L.
What behavioral changes were seen in PCMX-exposed zebrafish?▼
Zebrafish showed daytime hyperactivity and insomnia-like sleep fragmentation at night, along with impaired visuomotor responses to light-dark transitions.
References
- 1.Man X, Bao Y, Feng X. “Chloroxylenol impairs the visual system, induces visually-mediated behavioral abnormalities and circadian rhythm disorders in zebrafish (Danio rerio)..” Comparative biochemistry and physiology. Toxicology & pharmacology : CBP, 2026. PMID: 42442645 DOI: 10.1016/j.cbpc.2026.110616