Dose-Dependent Relationship between Protection of Thioacetamide-Induced Acute Liver Injury and Hyperammonemia and Concentration of Lactobacillus salivarius Li01 in Mice

Recently, probiotics have been widely used as an adjuvant therapy to cure, prevent, or improve certain diseases. However, no research has been carried out into the dose of probiotics, especially the maximum dose. Therefore, the effective and safe dosage of probiotics needs to be studied. Recently, L. Yang, X. Bian, W. Wu, L. Lv, et al. (Microb Biotechnol 13:1860–1876, 2020, https://doi.org/10.1111/1751-7915.13629) discovered that Lactobacillus salivarius Li01 had a protective effect on thioacetamide-induced acute liver injury and hyperammonemia, and a fixed concentration (3 × 10(9) CFU/mL) of L. salivarius Li01 was applied in their study. However, the most effective treatment concentration of L. salivarius Li01 remains unknown. Therefore, four concentration gradients of L. salivarius Li01 suspension were prepared for groups of mice to have different levels of bacterial colonization by gavage. Then, acute liver injury and hyperammonemia were induced via thioacetamide administration. By observation and detection, an inverted U-shaped protective effect from L. salivarius Li01 existed in thioacetamide-induced acute liver injury and hyperammonemia. Of note, significant deterioration was confirmed within the group that was orally administered with an excessive concentration of L. salivarius Li01 suspension, and this was attributed to endotoxemia that resulted from compromised immunity, a damaged intestinal barrier, and bacterial translocation. IMPORTANCE This research investigated the relationship between the concentration of Lactobacillus salivarius Li01 and its impact on mice that had a thioacetamide-induced acute liver injury and hyperammonemia. These findings could provide new insights into the effective, proper, and safe use of probiotics.