关键词: 乳酸杆菌, 降胆固醇, 小鼠, 筛选

Abstract:

Objective: To screen Lactobacillus with high cholesterol-degrading capacity from fresh sheep feces and
explore the effect of the screened strain on serum cholesterol level in hypercholesterolemic mice. Methods: We screened
Lactobacillus with high cholesterol-reducing capacity using Calcium Carbonate-Man-Rogosa-Sharp (MRS) medium
and cholesterol-MRS medium. The screened strain, named as L-3, was identified by colony morphology, physiological
and biochemical tests and 16S rDNA sequencing. A feeding experiment was conducted on forty Kunming male mice
(eight weeks old). The mice were randomly divided 4 groups: A, B, C and D, which were fed with normal diet, high
fat diet (HFD), HFD plus normal saline and HFD plus strain L-3, respectively. The serum levels of total cholesterol
(TC), triglyceride (TG), and high density lipoprotein-cholesterol (HDL-C) were determined on the 15th and 30th day of
the experiment. Results: This selected strain was identified as Lactobacillus plantarum L-3 and the degradation rate
of cholesterol by the stain could reach up to (35.93 ± 0.43)%. A hypercholesterolemic mice model was successfully
constructed after feeding a high-cholesterol diet for 15 days. Compared with group B, serum TC, TG and AI levels
were extremely significantly decreased in group D after 30 days of oral administration of strain L-3 (P < 0.01), HDL-C
levels of group D was significantly increased (P < 0.05), and HDL-C/TC levels were extremely significantly increased
(P < 0.01). However, the negative control group did not show cholesterol degradation (P > 0.05). Conclusion: L. plantarum
L-3 has probiotic potential as indicated by its hypocholesterolemic effect both in vivo and in vitro.

Key words: Lactobacillus, cholesterol degradation, mice, screening