Biology · Oct 12, 2026

Cigarette Smoke Extract Impairs Regeneration and Tissue Homeostasis in the Planarian Dugesia japonica and May Be Associated with Changes in MAPK-Related Signaling

By Zhao Z, Wang E, Yang K et al.

Cigarette smoke extract (CSE) is used to assess tobacco toxicity, but its effects on freshwater planarian regeneration remain incompletely characterized. We investigated CSE toxicity in Dugesia japonica using acute toxicity tests, phenotypic observation, biochemical assays, immunofluorescence, TUNEL staining, and transcriptomic and proteomic analyses. The 96 h median lethal concentration (LC₅₀) was 8.55% under the study-specific CSE definition. Exposure to 1% and 5% CSE impaired regeneration, with mortality and morphological abnormalities in the 5% group. CSE exposure also altered antioxidant and cholinergic enzyme activities, increased reactive oxygen species (ROS)-related fluorescence and malondialdehyde (MDA) content, and delayed neural remodeling. Fewer H3P-positive mitotic cells and more TUNEL-positive cells were observed, together with changes in proliferation- and apoptosis-related transcripts. Transcriptomic and proteomic analyses identified molecular responses involving stress, metabolism, and cellular homeostasis, although their overall concordance was low. Selected expression changes suggested mitogen-activated protein kinase (MAPK)-related signaling as a candidate response, but pathway activation and causal involvement were not established. These findings characterize regeneration impairment and associated cellular and molecular responses under laboratory CSE exposure conditions. They do not establish ecological risk at environmental exposure levels.

doi.org/10.3390/biology15201821 Open access PubMed 42939422 Mechanisms