A Lactiplantibacillus plantarum AL6-1 Strain Isolated From Air-Dried Meat Mitigates N-Dimethylnitrosamine-Induced Hepatic Injury in Mice

Excessive intake of N-dimethylnitrosamine (NDMA) can lead to liver damage and carries a potential carcinogenic risk. This study screened a strain of Lactiplantibacillus plantarum (L. plantarum) AL6-1 from traditional fermented products in Inner Mongolia. The strain not only has the ability to degrade NDMA efficiently (the degradation rate is 73.62%), but also has better tolerance than other strains, and it has strong adhesion. These functional characteristics were further verified by genome-wide sequencing. Functional genes related to antioxidant activity, DNA repair, and metabolic regulation were also identified in the genome data, which provided a molecular basis for the protection of the strain against liver injury. Animal experiment results showed that intervention with L. plantarum AL6-1 slowed weight gain in mice, reduced liver index, significantly improved liver tissue structure and reduced the degree of inflammatory cell infiltration, and significantly decreased serum alanine aminotransferase and aspartate aminotransferase levels (p < 0.05). Meanwhile, malondialdehyde and NDMA levels in mouse plasma were significantly reduced (p < 0.05), while superoxide dismutase and reduced glutathione levels were significantly increased (p < 0.05). Additionally, this strain ameliorated liver damage by regulating the expression of hepatic metabolic enzymes Cytochrome P450 2E1, Cytochrome P450 2C37, and Cytochrome P450 1A2. Therefore, the findings of this study provide a theoretical basis for the potential application of L. plantarum AL6-1 in alleviating NDMA-related liver damage.