Chloroxylenol (PCMX) at ≥0.4 mg/L induces ocular malformations and visual impairments, and at ≥1.2 mg/L disrupts circadian rhythms and sleep/wake behaviors in zebrafish larvae, with melatonin intervention alleviating sleep deficits.
Exposure to PCMX at concentrations ≥0.4 mg/L caused ocular malformations and suppressed photoreceptor development via disrupted thyroid hormone signaling in zebrafish larvae. At 2 and 2.8 mg/L, it impaired image-forming vision and visuomotor responses, while at ≥1.2 mg/L it disrupted circadian clock gene expression and induced daytime hyperactivity and insomnia-like sleep fragmentation, which were alleviated by melatonin treatment.
This article is automatically generated from the structured evidence profile behind the claim above. Scores reflect the quality and quantity of available research, not clinical advice.
Chloroxylenol (PCMX) at ≥0.4 mg/L induces ocular malformations and visual impairments, and at ≥1.2 mg/L disrupts circadian rhythms and sleep/wake behaviors in zebrafish larvae, with melatonin intervention alleviating sleep deficits. The current body of evidence comprises 1 study. EvidenceHub rates the overall confidence at 24/100 (low).
The Claim
Chloroxylenol (PCMX) at ≥0.4 mg/L induces ocular malformations and visual impairments, and at ≥1.2 mg/L disrupts circadian rhythms and sleep/wake behaviors in zebrafish larvae, with melatonin intervention alleviating sleep deficits.
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 expression of 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 visual-mediated behaviors; additionally, PCMX disrupts melanopsin gene rhythmicity and core clock gene expression, leading to circadian rhythm disorders and abnormal sleep/wake behaviors
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, limiting direct generalizability to humans or other mammals
- ▸No long-term exposure or recovery data provided; effects beyond larval stage not assessed
Frequently Asked Questions
What concentration of PCMX caused visual impairments in zebrafish?▼
Ocular malformations were observed at concentrations ≥0.4 mg/L, while impairments in image-forming vision and visuomotor responses occurred at 2 and 2.8 mg/L.
Did melatonin help with PCMX-induced sleep problems?▼
Yes, melatonin intervention effectively alleviated the sleep/wake behavioral deficits, including daytime hyperactivity and insomnia-like sleep fragmentation.
How does PCMX affect circadian rhythms?▼
At concentrations ≥1.2 mg/L, PCMX disrupted the rhythmic expression of core clock genes and melanopsin family genes in the non-image-forming visual system, leading to circadian rhythm disorders.
What is the ecological relevance of this study?▼
PCMX is frequently detected in aquatic environments, and this study shows it can impair vision, behavior, and circadian rhythms in zebrafish, indicating potential ecological risks to aquatic organisms.
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