Phoxim-induced damages ofBombyx morilarval midgut and titanium dioxide nanoparticles protective role under phoxim-induced toxicity

Abstract

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.

Studies on combined effect of Aeromonas hydrophila and cadmium on lipid peroxidation and antioxidant status in selected tissues of Indian freshwater major carp, Catla catla: role of silver nanoparticles

“…Moreover, it has also been shown that AgNPs with organic additive 1 exhibited cytotoxicity of mammalian cells, HepG2 cells as compared to AgNPs with organic additive 3 which exhibited lower cell toxicity of HepG2 cells (34). It is noteworthy to mention that TiO 2 NPs enhanced the antioxidant system against phoxim-induced oxidative stress in Bombyx mori (25). Further, it has been suggested that TiO 2 NPs have ability to act at the level of expression of resistancerelated genes and their proteins, including those encoding SOD, CAT, GPX, and GST, which in turn mitigate ROS in B. mori larvae under BmNPV infection (35).…”

“…Previously, we demonstrated that citrate-coated AgNPs plays an important role in energy metabolism as evidenced by a balance between aerobic to anaerobic marker enzymes succinate dehydrogenase and lactate dehydrogenase, respectively in AH infected fishes (8). Further, titanium dioxide nanoparticles protect silkworm, Bombyx mori against phoxim induced oxidative stress and neurotoxicity (24,25). Thus, it seems obvious that response of biological systems towards different combinations of NPs differ at the perspective of toxicological aspects.…”

“…Previous studies from our laboratory indicate that AgNPs showed enhanced activity levels of mitochondrial marker enzyme succinate dehydrogenase in AH infected gills, kidney and liver of fishes indicating the normal functional activity of mitochondria. Recently, studies of Xie et al and Su et al (24,25) reported that Titanium dioxide nanoparticles (TiO 2 NPs) protected brain tissue from oxidative stress induced by organophosphorus pesticide, phoxim in silk worm, Bombyx mori. The same authors indicated that TiO 2 NPs suppressed oxidative stress in selected tissues of insects might be due to regulation of expression of genes such as caspases which are believed to be important in oxidative stress and mitochondria and respiratory chain (24,25).…”

“…Recently, studies of Xie et al and Su et al (24,25) reported that Titanium dioxide nanoparticles (TiO 2 NPs) protected brain tissue from oxidative stress induced by organophosphorus pesticide, phoxim in silk worm, Bombyx mori. The same authors indicated that TiO 2 NPs suppressed oxidative stress in selected tissues of insects might be due to regulation of expression of genes such as caspases which are believed to be important in oxidative stress and mitochondria and respiratory chain (24,25). Recently, studies of Oliveira et al (34), indicated that AgNPs with organic additives such as (1) 5-Aminoisoquinoline, (2) 7-amino-4-methylcoumarin, and (3) 2-Aminoanthraceneas did not elicit same responses in pro-(malondialdehyde levels) and antioxidant enzymes such as CAT and GST in intestine and liver tissues of gold fish, Carassius auratus.…”

Application Of Nanotechnology In Agriculture And Food Industry, Its Prospects And Risks

“…Pre-treatment by TiO 2 NPs increased antioxidant capacity and acetylcholinesterase (AChE) activity in intoxicated silkworm and improved B. mori larval survival under phoxim-induced toxicity [199]. TiO 2 NPs pre-treatment also reduced the phoxim-induced brain damage of the 5th larval instar of B. mori; under phoxim exposure they relieved severe brain damage and oxidative stress in the brain and inhibited the down-regulated expression of H + -transporting ATP synthase and vacuolar ATP synthase that are involved in ion transport and energy metabolism [200].…”