Probiotic Potential of Limosilactobacillus reuteri JS-51 from Traditional Fermented Jiangshui: Screening, Characterization, and Hypocholesterolemic Effects

Hypercholesterolemia is a major risk factor for cardiovascular and hepatic diseases. Recently, probiotics have garnered significant attention as a promising, non-pharmacological approach to regulate lipid metabolism. In this study, we screened potential cholesterol-lowering lactic acid bacteria from Jiangshui, a traditional Chinese fermented vegetable beverage. Initially, 52 acid-producing isolates were obtained using CaCO3-supplemented MRS agar. Subsequent screening for bile salt hydrolase (BSH) activity yielded five promising strains. These isolates were further evaluated for gastrointestinal tolerance, cell surface hydrophobicity, and in vitro cholesterol removal capacity. Strain JS-51, identified as Limosilactobacillus reuteri via 16S rRNA sequencing, exhibited superior probiotic properties. It demonstrated high cell surface hydrophobicity (72.36 ± 1.24%), robust survival under harsh conditions (pH 3.0 and 0.5% bile salts), and the highest in vitro cholesterol removal rate (55.15 ± 1.87% at 48 h). The in vivo hypocholesterolemic efficacy of L. reuteri JS-51 was then evaluated in a high-fat diet-induced Sprague Dawley rat model. Following a four-week daily oral administration at doses of 106, 107, and 108 CFU/mL, JS-51 elicited a dose-dependent reduction in serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol (p < 0.001), alongside an increase in high-density lipoprotein cholesterol. Histopathological analysis revealed observable morphological amelioration of hepatic steatosis, a reduction in the liver index by up to 5.56%, and the restoration of normal hepatocyte architecture. These phenotypic findings indicate that L. reuteri JS-51 possesses robust in vitro probiotic potential and effective in vivo lipid-lowering capabilities, highlighting its potential as a functional starter culture or dietary supplement for managing hypercholesterolemia.