Anti-adipogenesis and metabolism-regulating effects of heat-inactivated Streptococcus thermophilus MN-ZLW-002

Metabolic syndrome and obesity have become serious threats to public health worldwide. This study was conducted to evaluate the anti-adipogenesis and metabolism-regulating effects of heat-inactivated Streptococcus thermophilus MN-ZLW-002 (MN-ZLW-002), which can be used as a yogurt starter. In vitro study suggested that MN-ZLW-002 stimulated the RAW264.7 macrophages to produce significant amounts of interleukin (IL)-6, IL-10 and tumour necrosis factor (TNF)-α and induced intense phosphorylation of P38, p44/42 MAPK and nuclear factor κB. MN-ZLW-002-stimulated RAW264.7-conditioned medium (CM) notably suppressed the differentiation and adipogenesis of 3T3-L1 pre-adipocytes. The 12-week in vivo study suggested that orally administered MN-ZLW-002 significantly reduced the weight gain of mice caused by the high-fat diet (HFD) at weeks 3–8; decreased fasting blood glucose levels at week 4 and week 8; decreased serum total triglyceride level at week 12. MN-ZLW-002 also reduced serum IL-1β and chemokine ligand 3 levels in the HFD-fed mice. These findings suggest that heat-inactivated MN-ZLW-002 can suppress adipocytes differentiation and lipid accumulation by regulating the immune response, possibly via the release of cytokines, particularly TNF-α; MN-ZLW-002 can improve metabolism-related indicators in the early stage of HFD intervention and regulate the related pro-inflammatory immune response.