Severe peripheral nerve injury (PNI) remains a major clinical challenge, and functional recovery after conventional neurorrhaphy is often unsatisfactory due to fascicular mismatch, suture tension, and Show more
Severe peripheral nerve injury (PNI) remains a major clinical challenge, and functional recovery after conventional neurorrhaphy is often unsatisfactory due to fascicular mismatch, suture tension, and limited Schwann cell viability. To address these limitations, we previously developed a small-gap chitosan-based conduit that provides a controlled microenvironment for regenerative interventions. This study aimed to investigate whether SOX5 overexpression enhances Schwann cell regenerative potential and, when combined with this conduit, synergistically promotes peripheral nerve regeneration. Schwann cells were transduced with SOX5 lentivirus and assessed for proliferation, migration, and neurotrophic factor secretion in vitro. In a rat sciatic nerve transection model (2-mm gap), animals received a chitosan conduit with intraluminal injection of SOX5 lentivirus. Histological, electrophysiological, and behavioral assessments were conducted at 12 weeks post-surgery. SOX5 overexpression significantly enhanced Schwann cell proliferation, migration, and secretion of BDNF, NGF, CNTF, and VEGF, while maintaining the dedifferentiated repair phenotype. In vivo, the combination of SOX5 lentivirus and chitosan conduit improved axonal regeneration, reduced muscle atrophy, and increased conduction velocity and locomotor recovery relative to the empty conduit group. Lentivirus-mediated SOX5 overexpression drives Schwann cells toward a repair phenotype and, when integrated with a small-gap chitosan-based conduit, effectively promotes structural and functional nerve regeneration. Show less
Peripheral nerve injuries often lead to significant functional impairment. While autografts remain the gold standard for repairing critical-sized nerve defects, donor site morbidity and limited graft Show more
Peripheral nerve injuries often lead to significant functional impairment. While autografts remain the gold standard for repairing critical-sized nerve defects, donor site morbidity and limited graft availability have prompted the exploration of alternative strategies. Although studies investigating nerve regeneration using nerve conduits and biological agents are present in the literature, research investigating the effect of neurotrophic factors enriched secretome with biocompatible 3D conduits combination is insufficient. The aim of this study is to evaluate the regenerative potential of 3D biodegradable chitosan-PCL nerve conduit combined with BDNF-enriched secretome in peripheral nerve defects. In this study, biodegradable three-dimensional (3D) nerve conduits composed of polycaprolactone (PCL) and chitosan (75:25 wt/wt) were fabricated and used to bridge 10 mm sciatic nerve defects in rats. The conduits were evaluated alone or in combination with the secretome derived from Wharton's Jelly mesenchymal stem cells (WJ-MSC), either in the native form or enriched with brain-derived neurotrophic factor (BDNF). Thirty-two adult male Wistar Albino rats (mean weight 300-400 g) were randomized into four groups: Autograft (Group 1), conduit only (Group 2), conduit and WJ-MSC derived secretome (Group 3), and conduit combined with BDNF-enriched WJ-MSC derived secretome (Group 4). Functional recovery was assessed using the sciatic functional index (SFI), electromyography (EMG), and gastrocnemius muscle wet weight. Morphological and histological evaluations were performed at 12 weeks postoperatively. At the end of 12 weeks, Group 4 (-49.48 ± 2.82) exhibited significantly improved SFI values compared to Group 2 (-66.62 ± 5.31) and Group 3 (-60.60 ± 5.34) (p < 0.05). Electromyographic analysis revealed higher compound muscle action potential amplitutes in Group 4 (19.72 ± 3.62 mV) than Group 2 and Group 3 (p < 0.05), with values compared to the autograft group. Gasrtrocnemius muscle wet weight ratios were also significantly higher in Group 4 (69.09% ± 9.88%) than in Groups 2 and 3. Histological analyses showed enhanced axonal regeneration, reduced inflammation, and better myelination in Group 4. Scanning electron microscopy confirmed the conduit structural integrity and stability over the 12-week period. The combination of a 3D biodegradable chitosan-PCL conduit with BDNF-enriched WJ-MSC-derived secretome significantly enhanced peripheral nerve regeneration in a rat model. This strategy shows strong potential as an alternative to autografts for treating critical-sized nerve defects. Show less
Brain aging is a multifactorial process associated with oxidative stress, chronic neuroinflammation, and synaptic dysfunction, ultimately leading to cognitive decline and increased susceptibility to n Show more
Brain aging is a multifactorial process associated with oxidative stress, chronic neuroinflammation, and synaptic dysfunction, ultimately leading to cognitive decline and increased susceptibility to neurodegenerative disorders. Epigallocatechin gallate (EGCG) is a potent antioxidant and anti-inflammatory agent, but its therapeutic potential is limited by poor stability and bioavailability. In this study, a dual nano delivery system was developed by loading chitosan-EGCG nanoparticles into mesenchymal stem cell-derived exosomes (Ex-Chit-EGCG NPs) and evaluated for neuroprotective efficacy in a D-galactose-induced brain aging model. Intranasal administration of Ex-Chit-EGCG NPs significantly improved cognitive and locomotor performance compared with exosomes alone, as evidenced by enhanced outcomes in Y-maze and open field tests. Biochemical analyses revealed that Ex-Chit-EGCG NPs effectively reduced lipid peroxidation, restored glutathione levels, and reactivated the LKB1/AMPK/SIRT1 signaling pathway. Molecular investigations demonstrated upregulation of Nrf2, BDNF, and SIRT1 together with suppression of NF-κB and Iba-1 expression, indicating attenuation of oxidative and inflammatory responses. Histopathological and immunohistochemical evaluations confirmed these findings, showing preservation of cortical and brain stem architecture with marked reductions in neuronal necrosis, gliosis, BAX, GFAP, and NLRP3 expression. Collectively, the results demonstrate that Ex-Chit-EGCG NPs exert superior neuroprotective effects compared with exosomes alone, highlighting the therapeutic advantage of combining EGCG with chitosan nanocarriers and exosomal delivery. This dual nanotherapeutic strategy offers a promising and non-invasive approach for mitigating brain aging and holds potential for translation into therapies targeting age-related neurodegenerative disorders. Show less
Post-traumatic stress disorder (PTSD) is a stressful mental illness that arises after exposure to unforeseen traumatic events. The majority of PTSD cases are often refractory to pharmacological interv Show more
Post-traumatic stress disorder (PTSD) is a stressful mental illness that arises after exposure to unforeseen traumatic events. The majority of PTSD cases are often refractory to pharmacological interventions. Herein, considering the neuroprotective effects of quercetin and chitosan in several brain disorders, we examined the effect of quercetin-loaded chitosan nanoparticles (QCNPs), administered via nose-to-brain delivery, on PTSD-like phenotypes in mice. QCNPs were synthesized using the ethanol injection method. We observed uniform spherical structure and 120-170 nm diameter of nanoparticles in transmission-electron microscopy analysis. The polydispersity index, zeta potential, and entrapment efficiency were 0.36 ± 0.0104, 39.05 mV, and 81.86 ± 1.60 %, respectively. Male C57BL/6 mice subjected to controlled-cortical impact (CCI) surgery followed by single-prolonged stress (SPS) exhibited PTSD-like symptoms, including deficits in sociability, anxiety and cognition. The CCI + SPS-driven neurobehavioral dysfunctions related to sociability index, anxiety-like phenotype, and cognition were evaluated employing social-approach social avoidance (SASA), elevated zero maze (EZM), Y-maze, and novel object recognition task (NORT). Intranasal delivery of QCNPs, at 0.06 mg/kg of body weight for 14 days, ameliorated CCI + SPS-generated PTSD-like behaviors in mice. The depleted levels of postsynaptic-density protein 95 (PSD-95), brain-derived neurotrophic factor (BDNF), and doublecortin in the hippocampus of CCI + SPS-exposed mice were restored following QCNPs treatment. Moreover, QCNPs administration reduced the expression of astrocyte marker glial-fibrillary acidic protein (GFAP), IBA-1, c-Fos, and proinflammatory cytokines (C-reactive protein, IL-6, TNF-α, and IL-1β) in the hippocampus of CCI + SPS group. These results suggest that nose-to-brain delivery of QCNPs reverses CCI + SPS-generated PTSD-like phenotypes by modulating neuroinflammatory mediators and enhancing neuronal and synaptic proteins. Show less