An integrated cell isolation and purification method for rat dorsal root ganglion neurons

Establishment of pseudorabies virus latency and reactivation model in mice dorsal root ganglia culture

Pseudorabies virus (PRV) belongs to the alpha herpesvirus family and is responsible for Aujeszky's disease in pigs. Similar to other alpha herpesviruses, PRV establishes a lifelong latent infection in trigeminal ganglion. These latently infected pigs serve as a reservoir for recurrent infections when reactivation is triggered, making the eradication of PRV a challenging task. However, the molecular mechanism underlying PRV latency and reactivation in neurons is still poorly understood due to limitations in the in vitro model. To establish a pseudorabies virus latency and reactivation model in primary neuron cultures, we isolated dorsal root ganglion (DRG) from newborn Kunming mice using a method named epineurium-pulling for DRG collection (EPDC) and cultured primary neurons in vitro. A dual-colour recombinant PRV BAC mRuby-VP16 was constructed and 0.5 multiplicity of infection (MOI) was found as an appropriate dose in the presence of aciclovir to establish latency. Reactivation was induced using UV-inactivated herpesviruses or a series of chemical inhibitors. Interestingly, we found that not only UV-PRV, but also UV-HSV-1 and UV-BHoV-5 were able to induce rapid PRV reactivation. The efficiency of reactivation for LY294002, forskolin, etoposide, dexamethasone, and acetylcholine was found to be dependent on their concentration. In conclusion, we developed a valuable model of PRV latency and reactivation, which provides a basis for future mechanism research.

The Chick Embryo and Its Structures as a Model System for Experimental Ophthalmology

The possibilities of using the chick embryo and its individual structures as a model system in experimental ophthalmology are considered. Cultures of the retina and spinal ganglia from chick embryos are used in the development of new methods for the treatment of glaucomatous optic neuropathy and ischemic optic neuropathy. The chorioallantoic membrane is used for modelling vascular pathologies of the eye, screening of anti-VEGF drugs, and assessing biocompatibility of implants. Co-culturing of chick embryo nervous tissue and human corneal cells makes it possible to study the processes of corneal reinnervation. The use of chick embryo cells and tissues in the "organ-on-a-chip" system opens up wide opportunities for fundamental and applied ophthalmological studies.

Dapsone improves the vincristine-induced neuropathic nociception by modulating neuroinflammation and oxidative stress

BACKGROUND

Peripheral neuropathy is a dose-limiting adverse effect of vincristine (VCR) in cancer chemotherapies. Dapsone is commonly used for the prevention of opportunistic infections following cancer therapies. Therefore, a high rate of VCR and dapsone co-administration has occurred in leukemias. Recently neuroprotective effects of dapsone have been reported in various diseases.

OBJECTIVES

Regarding the physiopathology of VCR-induced peripheral neuropathy (VIPN) and dapsone neuroprotection, this study evaluated the effect of dapsone on VIPN.

METHODS

VIPN was induced by VCR injection (0.5 mg/kg IP, every other day, 1 week) in male Wistar rats. In the treatment group, dapsone(12.5 mg/kg IP, 1 week) was injected 30 min before VCR. Hot plate, Von Frey, motor neuron conduction velocity (MNCV), and histopathological tests were applied. The levels of TNF-α and NF-kB in the sciatic nerve and caspase-3 activity in dorsal root ganglion were measured by the ELISA method. The levels of malondialdehyde (MDA) and Glutathione (GSH) in the sciatic nerve were measured by spectrophotometry and colorimetric assays.

RESULTS

VIPN was observed as araised thermal and mechanical threshold, reduced MNCV, and sciatic nerve demyelination. However, dapsone reduced the mechanical and thermal threshold and improved the MNCV. Also, dapsone reduced TNF-α, NF-kB, MDA, and Caspase-3 activity, and increased the GSH level in the sciatic nerve. Moreover, dapsone prevented VCR-induced demyelination in the sciatic nerve.

CONCLUSION

This research demonstrated that dapsone could be used as a protective drug against VIPN. It improves the impaired thermal and mechanical sensations by reducing inflammatory, oxidant, and apoptosis factors and preventing demyelination in the sciatic nerve.

Glutamine Maintains Satellite Glial Cells Growth and Survival in Culture

Satellite glial cells (SGCs) tightly surround neurons and modulate sensory transmission in dorsal root ganglion (DRG). At present, the biological property of primary SGCs in culture deserves further investigation. To reveal the key factor for SGCs growth and survival, we examined the effects of different culture supplementations containing Dulbecco's Modified Eagle Medium (DMEM)/F12, DMEM high glucose (HG) or Neurobasal-A (NB). CCK-8 proliferation assay showed an increased proliferation of SGCs in DMEM/F12 and DMEM/HG, but not in NB medium. Bax, AnnexinV, and propidium iodide (PI) staining results showed that NB medium caused cell death and apoptosis. We showed that glutamine was over 2.5 mM in DMEM/F12 and DMEM/HG, whereas it was absence in NB medium. Interestingly, exogenous glutamine application significantly reversed the poor proliferation and cell death of SGCs in NB medium. These findings demonstrated that DMEM/F12 medium was optimal to get high-purity SGCs. Glutamine was the key molecule to maintain SGCs growth and survival in culture. Here, we provided a novel approach to get high-purity SGCs by changing the key component of culture medium. Our study shed a new light on understanding the biological property and modulation of glial cells of primary sensory ganglia.

A Dual-Modal Magnetic Resonance/Photoacoustic Imaging Tracer for Long-Term High-Precision Tracking and Facilitating Repair of Peripheral Nerve Injuries

Neuroanatomical tracing is considered a crucial technique to assess the axonal regeneration level after injury, but traditional tracers do not meet the needs of in vivo neural tracing in deep tissues. Magnetic resonance (MR) and photoacoustic (PA) imaging have high spatial resolution, great penetration depth, and rich contrast. Fe₃ O₄ nanoparticles may work well as a dual-modal diagnosis probe for neural tracers, with the potential to improve nerve regeneration. The present study combines antegrade neural tracing imaging therapy for the peripheral nervous system. Fe₃ O₄ @COOH nanoparticles are successfully conjugated with biotinylated dextran amine (BDA) to produce antegrade nano-neural tracers, which are encapsulated by microfluidic droplets to control leakage and allow sustained, slow release. They have many notable advantages over traditional tracers, including dual-modal real-time MR/PA imaging in vivo, long-duration release effect, and limitation of uncontrolled leakage. These multifunctional anterograde neural tracers have potential neurotherapeutic function, are reliable and may be used as a new platform for peripheral nerve injury imaging and treatment integration.

Tissue-Specific Hydrogels for 3D Printing and Potential Application in Peripheral Nerve Regeneration

Decellularized extracellular matrix hydrogel (dECM-G) has demonstrated its significant tissue-specificity, high biocompatibility, and versatile utilities in tissue engineering. However, the low mechanical stability and fast degradation are major drawbacks for its application in 3D printing. Herein, we report a hybrid hydrogel system consisting of dECM-Gs and photocrosslinkable gelatin methacrylate (GelMA), which resulted in significantly improved printability and structural fidelity. These pre-mixed hydrogels retained high bioactivity and tissue-specificity due to their containing dECM-Gs. More specifically, it was realized that the hydrogel containing dECM-G derived from porcine peripheral nerves (GelMA/pDNM-G) effectively facilitated neurite growth and Schwann cell migration from 2D cultured dorsal root ganglion explants. The nerve cells were also encapsulated in the GelMA/pDNM-G hydrogel for 3D culture or underwent cell-laden bioprinting with high cell viability. The preparation of such GelMA/dECM-G hydrogels enabled the recapitulation of functional tissues through extrusion-based bioprinting, which holds great potential for applications in regenerative medicine.

Self-Assembling Peptide Scaffold Carrying Neural-Cell Adhesion Molecule-Derived Mimetic-Peptide Transplantation Promotes Proliferation and Stimulates Neurite Extension by Modulating Tau Phosphorylation and Calpain/Glycogen Synthase Kinase 3 beta (GSK-3β) in Neurons

BACKGROUND Self-assembling peptide scaffolds have been extensively applied in tissue engineering. Many investigations have modified self-assembling peptide scaffolds by integrating functional motifs, with promising applications. This study aimed to generate a novel RADA16 self-assembling peptide scaffold integrating a neural-cell adhesion molecule-derived mimetic-peptide (SIDRVEPYSSTAQ) and evaluated the effects on neuron proliferation. MATERIAL AND METHODS A 37-amino-acids peptide of RADA16-activation motif containing neural-cell adhesion molecule-derived mimetic-peptide (SIDRVEPYSSTAQ) was synthesized and self-assembled into a scaffold. Dorsal root ganglion (DRG) and spinal cord motor neurons (SCMN) were primarily isolated and identified. Neurons (DRG and SCMN) were divided into FRM, FRM-MP, and FRM-MP-LiCl groups. The adherence ability of neurons was evaluated using toluidine blue staining. Proliferation and apoptosis of neurons were assessed using CCK-8 and flow cytometry assay, respectively. Immunofluorescence assay was used to measure neurite extension. Western blot assay was used to assess GSK-3ß/p-GSK-3ß, Tau/p-Tau, and calpain expression in neurons. RESULTS FRM-MP-LiCl released multiple-peptide with higher efficiency. FRM-MP-LiCl significantly enhanced proliferation and inhibited apoptosis compared to FRM and FRM-MP groups (p.