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Chen et al. Microbiome Res Rep 2025;4:6 https://dx.doi.org/10.20517/mrr.2024.38 Page 5 of 14

Figure 1. The BSH activity of L. johnsonii CCFM1376 and L. johnsonii QJSWX160M2. BSH: Bile salt hydrolase.

Statistical analyses
The results of the data are displayed as means ± standard deviations. SPSS software was employed for
analysis of variance (ANOVA), with Tukey’s test for subsequent inter-group comparisons. If the P-value
[18]
from the test for variance homogeneity is less than 0.05, a non-parametric alternative is considered . In
graphical representations, the lack of identical letters between groups denotes a significant discrepancy (P <
0.05).

RESULTS
BSH activity of L. johnsonii CCFM1376
BSH can catalyze the hydrolysis of conjugated bile acids to form unconjugated bile acid bile acids and
amino acids (taurine and glycine) during the bile acid synthesis process. Strains with high BSH activity can
promote the enterohepatic circulation of cholesterol and bile acids in the body. Therefore, BSH activity is
one of the key factors in assessing a strain’s ability to regulate cholesterol metabolism. This study measured
the BSH activity of L. johnsonii CCFM1376 and L. johnsonii QJSWX160M2 to assess their potential to
alleviate hypercholesterolemia. L. johnsonii CCFM1376 exhibits hydrolytic activities of
-1
-1
-1
0.2780 μmol·min ·mL for taurodeoxycholic acid (TDCA) and 0.3022 μmol·min ·mL for glycodeoxycholic
-1
acid (GDCA), which are significantly higher than those of L. johnsonii QJSWX160M2, with activities of
-1
-1
0.0664 μmol·min ·mL for TDCA and 0.1237 μmol·min ·mL for GDCA [Figure 1].
-1
-1
The impact of L. johnsonii CCFM1376 on serum lipid levels in hypercholesterolemic mice
The main characteristic of hypercholesterolemia is an excessive increase in plasma cholesterol, especially the
“bad” cholesterol known as LDL-C. Epidemiological studies consistently indicate that this contributes
significantly to the onset of atherosclerosis and a range of cardiovascular diseases. To explore the impact of
L. johnsonii CCFM1376 on the serum lipid levels in mice with hypercholesterolemia, this study measured
the levels of TC, LDL-C, HDL-C, and TG in mouse serum, with a particular focus on TC and LDL-C as key
indicators for assessing hypercholesterolemia. After 8 weeks of a high-cholesterol diet, the levels of serum
TC and LDL-C in the mice of the model group were significantly higher compared to those in the control
group mice [P < 0.05, Figure 2A and B]. Compared to the model group, mice supplemented with
L. johnsonii CCFM1376 demonstrated a considerable drop in the concentration of serum TC and LDL-C