Phoxim-induced damages of Bombyx mori larval midgut and titanium dioxide nanoparticles protective role under phoxim-induced toxicity

Environ Toxicol. 2014 Dec;29(12):1355-66. doi: 10.1002/tox.21866. Epub 2013 Apr 18.


Phoxim (O,O-diethyl O-(alpha-cyanobenzylideneamino) phosphorothioate) is a powerful organophosphorus pesticide with high potential for Bombyx mori larvae of silkworm exposure. However, it is possible that during the phoxim metabolism, there is generation of reactive oxygen species (ROS) and phoxim may produce oxidative stress and neurotoxicity in an intoxicated silkworm. Titanium dioxide nanoparticles (TiO2 NPs) pretreatment has been demonstrated to increase antioxidant capacity and acetylcholinesterase (AChE) activity in organisms. This study was, therefore, undertaken to determine phoxim-induced oxidative stress and neurotoxicity to determine whether phoxim intoxication alters the antioxidant system and AChE activity in the B. mori larval midgut, and to determine whether TiO2 NPs pretreatment attenuates phoxim-induced toxicity. The findings suggested that phoxim exposure decreased survival of B. mori larvae, increased malondialdehyde (MDA), carbonyl and 8-OHdG levels, and ROS accumulation in the midgut. Furthermore, phoxim significantly decreased the activities of AChE, superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione-S-transferase (GST), and levels of ascorbic acid (AsA), reduced glutathione (GSH), and thiol in the midgut. TiO2 pretreatment, however, could increase AChE activity, and remove ROS via activating SOD, CAT, APX, GR, and GST, and accelerating AsA-GSH cycle, thus attenuated lipid, protein, and DNA peroxidation and improve B. mori larval survival under phoxim-induced toxicity. Moreover, this experimental system would help nanomaterials to be applied in the sericulture.

Keywords: Bombyx mori; antioxidative capacity; midgut; phoxim insecticide; survival; titanium dioxide nanoparticles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / metabolism
  • Ascorbic Acid / metabolism
  • Bombyx / drug effects
  • Bombyx / growth & development
  • Bombyx / metabolism
  • Gastrointestinal Tract / drug effects
  • Gastrointestinal Tract / pathology
  • Glutathione Transferase / metabolism
  • Insecticides / toxicity*
  • Larva / drug effects
  • Larva / metabolism
  • Nanoparticles*
  • Organothiophosphorus Compounds / toxicity*
  • Oxidative Stress
  • Protective Agents / pharmacology
  • Reactive Oxygen Species / metabolism
  • Titanium / pharmacology*


  • Antioxidants
  • Insecticides
  • Organothiophosphorus Compounds
  • Protective Agents
  • Reactive Oxygen Species
  • titanium dioxide
  • phoxim
  • Titanium
  • Glutathione Transferase
  • Ascorbic Acid