Lactobacillus Rhamnosus GG and Bifidobacterium Bifidum TMC3115 Can Affect the Development of Hippocampal Neurons Cultured in Vitro in a Strain-dependent Manner (P20-009-19)

Abstract

Abstract Objectives This study aimed to examine whether probiotics could morphologically or physiologically influence hippocampal neuron development. Methods Hippocampal neurons cultured in vitro were exposed to live or heat-inactivated Lactobacillus rhamnosus GG (LGG), or live or heat-inactivated Bifidobacterium bifidum TMC3115 (TMC3115), for either 6 or 24 h. Neuron viability was then tested using the methyl thiazolyl tetrazolium assay. Neuronal morphological changes and drebrin (DRB) and synaptophysin (SYP) protein levels were monitored using immunofluorescence. And the levels of DRB, SYP, and brain-derived neurotrophic factor (BDNF), and cAMP-response element binding protein (CREB) mRNA were detected using RT-PCR. The BDNF, CREB and phosphorylated-CREB (P-CREB) protein levels were detected by ELISA or Western blot assays. Results We found exposure to probiotics could enhance neuron viability, although no significant differences were found in neuronal morphology among the groups following exposure to the test bacteria. However, the synapse development-related proteins, DRB and SYP, as well as BDNF and P-CREB protein levels, were significantly altered in this specific culture system. Conclusions These results demonstrated that LGG and TMC3115 exposure can affect neuronal viability, along with synaptic and brain function development, in a strain-dependent manner, which may also be closely associated with the physiological and cultural conditions of each strain, The up-regulated P-CREB protein level may be one of the underlying mechanisms by which the tested bacteria, especially live TMC3115 following exposure for 24 h, are able to regulate neuronal BDNF protein production. Further studies are needed to explore other possible effects probiotic exposure may have on hippocampal neurons, as well as the corresponding mechanisms that underlie them. Funding Sources This work was funded by the National Natural Science Foundation of China (Grant number 81872606).