Gut remediation: a potential approach to reducing chromium accumulation using Lactobacillus plantarum TW1-1

Some lactobacilli have protective effects against some heavy metals in mammals, but the underlying mechanism is not fully understood. To evaluate the remediation potency and the mechanism of Lactobacillus against chromium (Cr) in mice, Lactobacillus plantarum TW1-1 was orally administrated to Kunming mice for 7 weeks during exposure to 1 mM K₂Cr₂O₇ in drinking water. Results showed that TW1-1 helped to decrease Cr accumulation in tissues and increase Cr excretion in feces, and may also attenuate alterations in oxidative stress and histopathological changes caused by Cr exposure. Moreover, the chromate reduction ability of fecal bacteria doubled after administration of TW1-1 upon Cr induction. MiSeq sequencing of fecal bacterial 16S rRNA genes revealed that the overall structures of gut microbiota was shifted by Cr exposure and partially restored by TW1-1. The abundances of 49 of the 79 operational taxonomic units altered by Cr were reversed by TW1-1. Based on these, we proposed a working model of TW1-1 against Cr: TW1-1 helps to remove Cr from the host and meanwhile acts as a regulator of gut microbiota, which aids in chromate reduction and provide protection against Cr. We call this process of remediation of heavy metal in the gut "gut remediation".