Live and Heat-Inactivated Streptococcus thermophilus MN-ZLW-002 Mediate the Gut–Brain Axis, Alleviating Cognitive Dysfunction in APP/PS1 Mice
Yujie Zhang, Yimei Wang, Zhimo Zhou, Yang Yang, Jincheng Zhao, Xiaohong Kang, Zhouyong Li, Xi Shen, Fang He, Ruyue Cheng
Abstract
Research on regulating brain functions with probiotics and postbiotics through the gut–brain axis is attracting attention, offering the possibility of adjuvant therapy for Alzheimer’s disease (AD). Three-month-old male APP/PS1 mice were gavaged with live and heat-inactivated S. thermophilus MN-002 for three months. This study demonstrated that live and heat-inactivated S. thermophilus MN-002 improved cognitive dysfunctions in APP/PS1 mice, especially in spatial memory. However, the main effects of live S. thermophilus MN-002 directly altered the intestinal microbiota composition and increased serum IL-1β and IL-6. Heat-inactivated S. thermophilus MN-002 increased colonic propionic acid levels and enhanced the hippocampus’s antioxidant capacity. Furthermore, the changes were more obvious in the high-dose group, such as astrogliosis in the hippocampus. These results indicate that different forms and doses of the same strain, S. thermophilus MN-002, can partly improve cognitive functions in AD model mice via the gut–brain axis.