Antiobesity Effect of Novel Probiotic Strains in a Mouse Model of High-Fat Diet–Induced Obesity

Obesity is one of the major causes of the development of metabolic diseases, particularly cardiovascular diseases and type-2 diabetes mellitus. Increased lipid accumulation and abnormal adipocyte growth, which is an increase in cell numbers and differentiation, have been documented as major pathological characteristics of obesity. Thus, the inhibition of adipogenic differentiation prevents and suppresses obesity. Recently, specific probiotic strains have been known to regulate lipid metabolism in vitro and/or in vivo. Previously, we demonstrated that Lactobacillus johnsonni 3121 and Lactobacillus rhamnosus 86 could act as novel probiotic strains and reduce cholesterol levels. Moreover, both strains significantly reduced lipid accumulation and inhibited adipocyte differentiation by downregulating the adipogenic transcription factor in 3T3-L1 adipocytes. Therefore, L. johnsonni 3121 and L. rhamnosus 86 were selected for in vivo evaluation of their anti-obesity effects using a high-fat diet-induced obese mouse model. Daily oral administration of L. johnsonni 3121 and L. rhamnosus 86 for 12 weeks significantly improved serum lipid profile and downregulated the expression of genes related to adipogenesis and lipogenesis in epididymal white adipose tissue of high-fat diet fed obese mice (p < 0.05). Fecal analysis also suggested that the two probiotic strains could normalize the altered obesity–related gut microbiota in high-fat diet–fed obese mice. These results collectively demonstrate that oral administration of L. johnsonni 3121 and L. rhamnosus 86 could prevent obesity, thereby improving metabolic health.