Gut Dysbiosis and Neurobehavioral Alterations in Rats Exposed to Silver Nanoparticles

Abstract

Due to their antimicrobial properties, silver nanoparticles (AgNPs) are being used in non-edible and edible consumer products. It is not clear though if exposure to these chemicals can exert toxic effects on the host and gut microbiome. Conflicting studies have been reported on whether AgNPs result in gut dysbiosis and other changes within the host. We sought to examine whether exposure of Sprague-Dawley male rats for two weeks to different shapes of AgNPs, cube (AgNC) and sphere (AgNS) affects gut microbiota, select behaviors, and induces histopathological changes in the gastrointestinal system and brain. In the elevated plus maze (EPM), AgNS-exposed rats showed greater number of entries into closed arms and center compared to controls and those exposed to AgNC. AgNS and AgNC treated groups had select reductions in gut microbiota relative to controls. Clostridium spp., Bacteroides uniformis, Christensenellaceae, and Coprococcus eutactus were decreased in AgNC exposed group, whereas, Oscillospira spp., Dehalobacterium spp., Peptococcaeceae, Corynebacterium spp., Aggregatibacter pneumotropica were reduced in AgNS exposed group. Bacterial reductions correlated with select behavioral changes measured in the EPM. No significant histopathological changes were evident in the gastrointestinal system or brain. Findings suggest short-term exposure to AgNS or AgNC can lead to behavioral and gut microbiome changes.

Dietary exposure to silver nitrate compared to two forms of silver nanoparticles in rainbow trout: bioaccumulation potential with minimal physiological effects

“…33 Rats receiving a daily administration of 3.6 mg kg −1 by gavage of cubic or spherical Ag NPs (20 mL kg −1 body weight) for 14 days also showed no evidence of histological disturbance to the stomach, small intestine, cecum or colon. 34 Exposure to dissolved silver via the water is known to interfere with branchial sodium homeostasis in trout. 35 However, dietary silver generally does not.…”

Toward Synthesis-derived Applications of Silver Nanoparticles

“…It is generally accepted that silver nanoparticles, as well as many other engineered nanoparticles alter the human and animal microbiota. This alteration is mostly associated with dysfunctions which are correlated with the size and shape of the silver nanoparticles (AgNC -silver nanocubes and AgNSsilver nanospheres) [132][133][134][135][136]. Considering the most representative species of the microbiota it was found that Clostridium spp., Bacteroides uniformis, Christensenellaceae, and Coprococcuseutactus were decreased in AgNC exposed group, whereas, Oscillospira spp., Dehalobacterium spp., Peptococcaeceae, Corynebacterium spp., Aggregatibacterpneumotropica were reduced in AgNS exposed group.…”

Toward Synthesis-derived Applications of Silver Nanoparticles

“…It is generally accepted that silver nanoparticles, as well as many other engineered nanoparticles alter the human and animal microbiota. This alteration is mostly associated with dysfunctions which are correlated with the size and shape of the silver nanoparticles (AgNC -silver nanocubes and AgNSsilver nanospheres) [130][131][132][133][134]. Considering the most representative species of the microbiota it was found that Clostridium spp., Bacteroides uniformis, Christensenellaceae, and Coprococcuseutactus were decreased in AgNC exposed group, whereas, Oscillospira spp., Dehalobacterium spp., Peptococcaeceae, Corynebacterium spp., Aggregatibacterpneumotropica were reduced in AgNS exposed group.…”