Peripheral nerve injury (PNI) leads to a series of cellular and molecular events necessary for axon regeneration and reinnervation of target tissues, among which inflammation is crucial for the orchestration of all these processes. Macrophage activation underlies the pathogenesis of PNI and is characterized by morphological/phenotype transformation from proinflammatory (M1) to an anti-inflammatory (M2) type with different functions in the inflammatory and reparative process. The aim of this study was to evaluate influence of the vitamin B (B1, B2, B3, B5, B6, and B12) complex on the process of neuroinflammation that is in part regulated by l-type CaV1.2 calcium channels. A controlled transection of the motor branch of the femoral peripheral nerve was used as an experimental model. Animals were sacrificed after 1, 3, 7, and 14 injections of vitamin B complex. Isolated nerves were used for immunofluorescence analysis. Treatment with vitamin B complex decreased expression of proinflammatory and increased expression of anti-inflammatory cytokines, thus contributing to the resolution of neuroinflammation. In parallel, B vitamins decreased the number of M1 macrophages that expressed the CaV1.2 channel, and increased the number of M2 macrophages that expressed this channel, suggesting their role in M1/M2 transition after PNI. In conclusion, B vitamins had the potential for treatment of neuroinflammation and neuroregeneration and thereby might be an effective therapy for PNI in humans.

It is well known that the peripheral nervous system has a good potential for regeneration. The aim of this study was to explore the effects of vitamin B therapy (with a complex of vitamins B1, B2, B3, B5, B6, and B12) on motor nerve recovery after femoral nerve injury. Our study was conducted on an experimental animal model of femoral nerve injury in rats. All animals used in the experiment were subjected to the same set of analyses. A behavior test was used for the assessment of motor function recovery. Body weight was measured and electromyography was performed in order to assess recovery of quadriceps muscle. Samples of muscles and nerves were used for counting nuclei and determining nuclear density. The results of this study showed enhanced functional recovery, including improved walking, a decreased level of muscle atrophy and better electromyography recovery after administration of vitamin B complex. Further, after 14 days of treatment with the vitamin B complex nuclear nerve and muscle density was significantly lowered. In conclusion, using a model of femoral nerve injury we demonstrated that the application of vitamin B complex improved recovery of motor nerve in rats. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 175033]

Peripheral nerve injury (PNI) triggers a complex multi-cellular response involving the injured neurons, Schwann cells (SCs), and immune cells, often resulting in poor functional recovery. The aim of this study was to investigate the effects of the treatment with vitamin B (B1, B2, B3, B5, B6, and B12) complex on the interaction between macrophages and SCs during the recovery period after PNI. Transection of the motor branch of the femoral nerve followed by reconstruction by termino-terminal anastomosis was used as an experimental model. Isolated nerves from the sham (S), operated (O), and operated groups treated with the B vitamins (OT group) were used for immunofluorescence analysis. The obtained data indicated that PNI modulates interactions between macrophages and SCs in a time-dependent manner. The treatment with B vitamins complex promoted the M1-to M2-macrophage polarization and accelerated the transition from the non-myelin to myelin-forming SCs, an indicative of SCs maturation. The effect of B vitamins complex on both cell types was accompanied with an increase in macrophage/SC interactions, all of which correlated with the regeneration of the injured nerve. Clearly, the capacity of B vitamins to modulate macrophages-SCs interaction may be promising for the treatment of PNI.

No abstract

The present study aimed to investigate the neuroprotective effects of the vitamin B complex (B1, B2, B3, B5, B6, and B12—VBC), by studying the changes in the femoral nerve, quadriceps muscle, popliteal lymph nodes and gut microbiota in the rat model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). VBC treatment attenuated clinical signs of EAE during the disease, and reduced the duration of EAE thereby contributing to a faster recovery. In VBC-treated EAE rats, a significant decrease in nerve and muscle nuclear density was revealed during the onset period of the disease, while a marked increase was detected at the end of the disease, compared with untreated EAE rats. In the lymph nodes of VBC-treated EAE rats, a fewer number of lymphoid follicles in the cortical area and smaller epithelioid granulomas were detected. The changes in microbiota composition were examined using 16S rRNA gene sequencing and bioinformatics analysis, which revealed the potential of VBC treatment in establishing and/or maintaining gut microbiota homeostasis. Finally, the present study demonstrated that VBC treatment ameliorated the cellular changes in the affected peripheral nerve, muscles innervated by this nerve, and the gut microbiota dysbiosis which occurred during the EAE.