Enantioselective Toxicity and Multilevel Effects of the Pyrethroid Insecticide Tefluthrin on the Silkworm, Bombyx mori
Sijuan Yin, Yuepeng Qiu, Yan Lv, Jun Xu, HuaiYuan Liu, Chang Li, Hongxin Wu, Ge Liu, Ting Tang, Lianshan Li, Fengsong LiuAbstract
Chiral pesticides often exhibit enantioselective toxicity, yet the enantiomer-specific effects of tefluthrin on silkworm (Bombyx mori) remain poorly understood. This study evaluated the toxicological impacts of racemic tefluthrin and its enantiomers, (1R,3R)- and (1S,3S)-tefluthrin, on silkworms using multilevel assays. Acute toxicity tests revealed strong enantioselectivity: (1R,3R)-tefluthrin was highly toxic (96-h LC50 = 1.27 mg/L), whereas (1S,3S)-tefluthrin showed low toxicity (LC50 > 200 mg/L). Sublethal exposure to (1R,3R)-tefluthrin and rac-tefluthrin significantly disrupted growth and reproduction, whereas (1S,3S)-tefluthrin exerted minimal effects. Histopathological and biochemical analyses showed that (1R,3R)-tefluthrin induced severe silk gland damage, DNA fragmentation, and oxidative stress, while (1S,3S)-tefluthrin had no significant impacts. Transcriptomic profiling further identified differential expression of genes associated with the p53 signaling pathway, cellular senescence, and voltage-gated sodium channels (Nav). These findings highlight the necessity of enantiomer-specific assessment in the ecological risk evaluation and rational management of chiral pesticides.