Lactobacillus rhamnosus GG and Bifidobacterium bifidum TMC3115 Can Affect Development of Hippocampal Neurons Cultured In Vitro in a Strain-Dependent Manner.

This study examined whether Lactobacillus rhamnosus GG (LGG) and Bifidobacterium bifidum TMC3115 (TMC3115) could morphologically or physiologically influence hippocampal neuronal development in vitro. Hippocampal neurons cultured in vitro were exposed to live or heat-inactivated LGG or TMC3115 for either 6 or 24 h. 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 extraction-enzyme-linked immunosorbent assay (ELISA) or Western blot assays. Heat-inactivated LGG and TMC3115 could enhance neuron viability, DRB and SYP protein levels, and BDNF mRNA level were significantly altered after exposure to the tested bacteria with 6 h or 24 h. There were no significant differences in neuronal morphology or DRB, SYP, or CREB mRNA levels among the groups following bacterial exposure. However, following exposure of live TMC3115 for 24 h, the neuronal BDNF and P-CREB protein levels were both significantly up-regulated as detected by western blot assays. These results demonstrated that LGG and TMC3115 could affect neuronal viability, along with hippocampal synaptic and functional development, in a strain-dependent manner, which may also be closely associated with the physiological and culture conditions of each strain. Up-regulated P-CREB may be one of the underlying mechanisms by which the bacteria, especially neurons following exposure of live TMC3115 for 24 h, are able to regulate neuronal BDNF protein production.

[Study on using a new biodegradable conduit to repairing rat's peripheral nerve defect].

OBJECTIVE: Nerve conduit, a new way to repair peripheral nerve, has good prospect. Now, the main obstacle of the conduit's clinical using is the absence of material with both ideal physical property and good biocompatibility. In this study, the PLA is added to chitosan to form a novel material used to make a new nerve conduit. And the rat modal is used to get the data of the nerve conduit made of new material to repair the defect of peripheral nerve in vivo. METHODS: Chitosan-PLA Composite Biodegradable material was used to produce a nerve conduit with depth of 200 um, diameter of 1.5 mm. This new conduit was used to repair the sciatic nerve's defect of 5 mm long. The other two groups as control groups repairs the same defects using silicon conduit or nerve's autograft respectively. 12 weeks after operation, normal assessments were performed including movement of hindlimb, hindlimb's retraction after being pricked by needle and ulcer in claw's palm. Special assessment was performed including histology, ECG, image analysis and weighing of triceps muscle of calf. The data of three groups was statistically analyzed by group t test. RESULTS: As the normal observation showing: after 12 weeks, the regenerating nerve succeeded to path through the gap and dominated the muscle. Special assessment including ECG, image analysis and weighing of triceps muscle of calf showed that the group using Chitosan-PLA Composite conduit had the nervous regeneration better than silicon conduit group both in the nerve's quality and in axon's quantity. And the nervous regeneration of Chitosan-PLA Composite conduit group was as good as that of nervous autograft's group. CONCLUSIONS: Chitosan-PLA Composite Biodegradable conduit could repair the defect of peripheral nerves successfully. It is an ideal material for nerve conduit.