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Replacement of peripheral nerve autografts with tissue engineered nerve grafts will potentially resolve the lack of nerve tissue especially in patients with severe concomitant soft tissue injuries. This study attempted to fabricate a tissue engineered nerve graft composed of electrospun PCL conduit filled with collagen-hyaluronic acid (COL-HA) sponge with different COL-HA weight ratios including 100:0, 98:2, 95:5 and 90:10. The effect of HA addition on the sponge porosity, mechanical properties, water absorption and degradation rate was assessed. A good cohesion between the electrospun PCL nanofibers and COL-HA sponges were seen in all sponges with different HA contents. Mechanical properties of PCL nanofibrous layer were similar to the rat sciatic nerve; the ultimate tensile strength was 2.23 ± 0.35 MPa at the elongation of 35%. Additionally, Schwann cell proliferation and morphology on three dimensional (3D) composite scaffold were evaluated by using MTT and SEM assays, respectively. Rising the HA content resulted in higher water absorption as well as greater pore size and porosity, while a decrease in Schwann cell proliferation compared to pure collagen sponge, although reduction in cell proliferation was not statistically significant. The lower Schwann cell proliferation on the COL-HA was attributed to the greater degradation rate and pore size of the COL-HA sponges. Also, dorsal root ganglion assay showed that the engineered 3D construct significantly increases axon growth. Taken together, these results suggest that the fabricated 3D composite scaffold provide a permissive environment for Schwann cells proliferation and maturation and can encourage axon growth.
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Nanofibras/química , Regeneración Nerviosa , Poliésteres/química , Andamios del Tejido/química , Animales , Proliferación Celular , Células Cultivadas , Nanofibras/ultraestructura , Ratas Wistar , Células de Schwann/citología , Ingeniería de Tejidos/métodosRESUMEN
Endoplasmic reticulum (ER) stress is strictly linked to neuroinflammation and involves in the development of neurodegenerative disorders. Protein disulfide isomerase (PDI) is an enzyme that catalyzes formation and isomerization of disulfide bonds and also acts as a chaperone that survives the cells against cell death by removal of misfolded proteins. Our previous work revealed that PDI is explicitly upregulated in response to myelin oligodendrocyte glycoprotein (MOG)-induced ER stress in the brain of experimental autoimmune encephalomyelitis (EAE) mice. The significance of overexpression of PDI in the apoptosis of neural cells prompted us to study the effect of CCF642, efficient inhibitor of PDI, in the recovery of EAE clinical symptoms. Using this in vivo model, we characterized the ability of CCF642 to decrease the expression of ER stress markers and neuroinflammation in the hippocampus of EAE mice. Our observations suggested that CCF642 administration attenuates EAE clinical symptomsand the expression of ER stress-related proteins. Further, it suppressed the inflammatory infiltration of CD4 + T cells and the activation of hippocampus-resident microglia and Th17 cells. We reported here that the inhibition of PDI protected EAE mice against neuronal apoptosis induced by prolonged ER stress and resulted in neuroprotection.
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The role of endoplasmic reticulum (ER) stress has been proposed in several neurodegenerative and autoimmune diseases and may contribute to neural apoptosis. The complex role of ER stress-mediated apoptosis introduces a novel angle on multiple sclerosis (MS) research. Nevertheless, the mechanisms through which ER stress intermediates apoptosis are not entirely understood. To this aim, we examined the expression of C/EBP homologous protein (CHOP), caspase-12, and protein disulfide isomerase (PDI) in mice with experimental autoimmune encephalomyelitis (EAE). We found the upregulated expression of CHOP, caspase-12, and PDI in the brain of EAE mice in comparison to healthy mice. Furthermore, immunofluorescent dual-label staining verified elevated levels of caspase-12/CHOP in astrocytes, oligodendrocytes, and microglia in the hippocampus section of EAE mice. This study highlighted the presence of ER stress and increased activation of caspase-12 in the hippocampus of mice in response to EAE induction. Higher levels of caspase-12/CHOP in hippocampal oligodendrocytes as compared with microglia and astrocytes denote that oligodendrocytes are particularly sensitive to ER-mediated apoptosis. In conclusion, the regulation of ER stress pathway would be beneficial for the survival of oligodendrocyte.
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Caspasa 12/metabolismo , Encefalomielitis Autoinmune Experimental/metabolismo , Factor de Transcripción CHOP/metabolismo , Animales , Apoptosis/genética , Astrocitos/metabolismo , Encéfalo/metabolismo , Caspasa 12/genética , Modelos Animales de Enfermedad , Encefalomielitis Autoinmune Experimental/genética , Retículo Endoplásmico/metabolismo , Estrés del Retículo Endoplásmico/genética , Estrés del Retículo Endoplásmico/fisiología , Femenino , Hipocampo/metabolismo , Ratones , Ratones Endogámicos C57BL , Neuronas/metabolismo , Oligodendroglía/metabolismo , Proteína Disulfuro Isomerasas/genética , Proteína Disulfuro Isomerasas/metabolismo , Factor de Transcripción CHOP/genéticaRESUMEN
Multiple sclerosis (MS) is a disease of the central nervous system (CNS) in which both neuroinflammation and neurodegeneration play critical roles in the pathogenesis of the disease. A growing body of evidence indicates that some antibiotics have anti-inflammatory and neuroprotective properties. Rifampicin, commonly used for the treatment of mycobacteria, has been shown to exert neuroprotective activities in neurodegenerative diseases. In this study, we examined the efficacy of rifampicin on demyelination, gliosis, apoptosis, inflammation, behavioral dysfunction, and biochemical alterations in the cuprizone model of demyelination. For this aim, male C57BL/6J mice were fed a chow containing 0.2% cuprizone (w/w) for 6â¯weeks to induce reversible demyelination in the corpus callosum. Mice intraperitoneally received serial doses of rifampicin (10, 20, or 40â¯mg/kg body weight) in the last 7â¯days of a 6-week period of cuprizone treatment. The results showed that the administration of rifampicin led to the improvement in motor behavioral deficits. In line with this, rifampicin decreased the number of apoptotic cells in the corpus callosum thereby diminishing the expression of cleaved caspase-3 and Bax, as well as increasing Bcl-2. Moreover, rifampicin significantly lowered the levels of interleukin-6, interleukin-1ß, caspase-12 activity, heme oxygenase-1(HO-1), nitric oxide (NO), and malondialdehyde (MDA) in mice treated with cuprizone. Conversely, the activity of glutathione peroxidase (GPx) and the level of ferric reducing ability of plasma (FRAP) were increased in response to the treatment with rifampicin. Histopathological findings demonstrated that rifampicin statistically promoted remyelination and mitigated microgliosis and astrogliosis. It seems that rifampicin is able to be added to the armamentarium of therapies for multiple sclerosis.
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Conducta Animal/efectos de los fármacos , Cuerpo Calloso , Cuprizona/efectos adversos , Enfermedades Desmielinizantes , Rifampin/farmacología , Animales , Cuerpo Calloso/metabolismo , Cuerpo Calloso/patología , Cuprizona/farmacología , Enfermedades Desmielinizantes/inducido químicamente , Enfermedades Desmielinizantes/tratamiento farmacológico , Enfermedades Desmielinizantes/metabolismo , Enfermedades Desmielinizantes/patología , Masculino , RatonesRESUMEN
In the field of nerve tissue engineering, nanofibrous scaffolds could be a promising candidate when they are incorporated with electrical cues. Unique physico-chemical properties of gold nanoparticles (AuNPs) make them an appropriate component for increasing the conductivity of scaffolds to enhance the electrical signal transfer between neural cells. The aim of this study was fabrication of AuNPs-doped nanofibrous scaffolds for peripheral nerve tissue engineering. Polycaprolactone (PCL)/chitosan mixtures with different concentrations of chitosan (0.5, 1 and 1.5) were electrospun to obtain nanofibrous scaffolds. AuNPs were synthesized by the reduction of HAuCl4 using chitosan as a reducing/stabilizing agent. A uniform distribution of AuNPs with spherical shape was achieved throughout the PCL/chitosan matrix. The UV-Vis spectrum revealed that the amount of gold ions absorbed by nanofibrous scaffolds is in direct relationship with their chitosan content. Evaluation of electrical property showed that inclusion of AuNPs significantly enhanced the conductivity of scaffolds. Finally, after 5 days of culture, biological response of Schwann cells on the AuNPs-doped scaffolds was superior to that on as-prepared scaffolds in terms of improved cell attachment and higher proliferation. It can be concluded that the prepared AuNPs-doped scaffolds can be used to promote peripheral nerve regeneration.
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Quitosano/química , Oro/química , Nanopartículas del Metal/química , Regeneración Nerviosa , Poliésteres/química , Ingeniería de Tejidos/instrumentación , Andamios del Tejido/química , Animales , Animales Recién Nacidos , Materiales Biocompatibles/química , Proliferación Celular , Iones/química , Microscopía Electrónica de Rastreo , Nanofibras/química , Sistema Nervioso Periférico , Ratas , Ratas Wistar , Células de Schwann , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de Fourier , Rayos UltravioletaRESUMEN
Microglia are the resident macrophages patrolling the central nervous system (CNS) to find dangerous signals and infectious agents mediating catastrophic cascades resulting in neuronal degeneration. Their morphological and biochemical properties made them enable to swift activation in response to neural insults and site-directed phagocytosis. Beside of beneficial roles in homeostasis of the brain and spinal cord, microglia can be participating in neuronal destruction and propagation of inflammation when they are unregulated or hyper-activated. A large body of research indicates that various cluster of differentiations (CDs) contribute to flame/quench the inflammatory processes occurred in immune system. In this study, we investigated the expression of CD36 and CD44 in LPS-activated primary rat microglia in response to treatment of minocycline at the levels of protein and gene using flow cytometry and real-time PCR, respectively. The results showed that minocycline decreased the expression of CD36 in cells treated with minocycline with respect to cells treated with LPS. Inversely, the expression of CD44 was increased in cells treated with minocycline in comparison to LPS-induced microglia. It seems that minocycline can modulate the expression of CDs involved in inflammatory reactions and enrich the armamentarium of therapeutic agents used for the treatment of neuroinflammatory and neurodegenerative disorders.
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Antibacterianos/farmacología , Antígenos CD36/efectos de los fármacos , Receptores de Hialuranos/efectos de los fármacos , Microglía/efectos de los fármacos , Minociclina/farmacología , Animales , Antígenos CD36/biosíntesis , Células Cultivadas , Receptores de Hialuranos/biosíntesis , Inflamación/inducido químicamente , Inflamación/inmunología , Inflamación/metabolismo , Lipopolisacáridos/farmacología , Microglía/inmunología , Microglía/metabolismo , Ratas , Ratas WistarRESUMEN
The peripheral nerve regeneration is still one of the major clinical problems, which has received a great deal of attention. In this study, the electrospun silk fibroin (SF)/poly(ethylene oxide) (PEO) nanofibrous scaffolds were fabricated and functionalized their surfaces with laminin (LN) without chemical linkers for potential use in the peripheral nerve tissue engineering. The morphology, surface chemistry, thermal behavior and wettability of the scaffolds were examined to evaluate their performance by means of scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and water contact angle (WCA) measurements, respectively. The proliferation and viability of Schwann cells onto the surfaces of SF/PEO nanofibrous scaffolds were investigated using SEM and thiazolyl blue (MTT) assay. The results showed an improvement of SF conformation and surface hydrophilicity of SF/PEO nanofibers after methanol and O2 plasma treatments. The immunostaining observation indicated a continuous coating of LN on the scaffolds. Improving the surface hydrophilicity and LN functionalization significantly increased the cell proliferation and this was more prominent after 5 days of culture time. In conclusion, the obtained results revealed that the electrospun LN-functionalized SF/PEO nanofibrous scaffold could be a promising candidate for peripheral nerve tissue regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1595-1604, 2018.
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Fibroínas , Laminina , Nanofibras/química , Regeneración Nerviosa/efectos de los fármacos , Polietilenglicoles , Nervio Ciático , Animales , Adhesión Celular , Proliferación Celular/efectos de los fármacos , Fibroínas/química , Fibroínas/farmacología , Laminina/química , Laminina/farmacología , Polietilenglicoles/química , Polietilenglicoles/farmacología , Ratas , Ratas Wistar , Células de Schwann/metabolismo , Nervio Ciático/lesiones , Nervio Ciático/metabolismo , Nervio Ciático/fisiologíaRESUMEN
Microglia are one of the most important neural cells in the central nervous system (CNS) which account for 10-15% of all cells found in the brain. A vast majority of studies indicate that microglia play a pivotal role in protection and damage of the CNS. It has been shown that microglia are mainly scavenger cells but also produce a barrage of factors that are involved in tissue repair and neural regeneration. Several lines of evidence indicate that unregulated activation of microglia in response to either endogenous or exogenous insults results in the production of toxic factors that propagate neuronal injury. Studies demonstrated that the activated microglia secret the excessive amounts of quinolinic acid (QA) and kynurenic acid (KYNA) which are highly toxic for the neuronal cells. In line with this, indolamine 2, 3 dioxygenase (IDO), an enzyme producing KYNA and QA has been shown to be elevated during the inflammation in microglia. In this study, we established primary microglial cell cultures obtained from cerebral cortices of 1-day neonatal Wistar rats. Minocycline (20-60⯵M) or its vehicle was added to the culture media 60â¯min prior to 48â¯h incubation with lipopolysaccharide (LPS; 10â¯ng/mL). Using a specific process of adhesion and shaking of the cultured glial cells, a purified culture of approximately 94% enriched microglia was obtained and then, corroborated by immunocytochemistry (ICC). The cell viability after minocycline treatments was assessed using the MTT colorimetric assay. The expression of IDO was evaluated using qPCR. The levels of KYNA and QA were determined using enzyme-linked immunosorbent assay (ELISA). The results showed that minocycline significantly decreased the levels of both KYNA and QA in glia cells exposed to LPS. Moreover, minocycline decreased the expression of IDO in treated LPS-induced microglia. It seems that minocycline has a potent ability to oppress the inflammatory process via the decrease in production of IDO expression and the concentrations of KYNA and QA.
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Indolamina-Pirrol 2,3,-Dioxigenasa/metabolismo , Ácido Quinurénico/metabolismo , Lipopolisacáridos/farmacología , Microglía/efectos de los fármacos , Minociclina/farmacología , Ácido Quinolínico/metabolismo , Animales , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Microglía/metabolismo , Neuroglía/efectos de los fármacos , Neuroglía/metabolismo , Ratas , Ratas WistarRESUMEN
Treatment of spinal cord injury by exogenous cells has brought both successful and unsuccessful results. Olfactory ensheathing cells and Schwann cells have been widely used for transplantation purposes. In this study, we investigated the effects of these cells on contused spinal cord by introducing cells into subarachnoid space. Fifty thousand Schwann cells or olfactory ensheathing cells or a mixture of both cell types were transplanted one week after a 3-second clip compression injury at T-9 spinal cord level in rats. Starting from the day one of spinal cord injury, animals were assessed for six months by BBB test and then were sacrificed for immunohistochemistry labeling of the spinal cord injury site. There was no locomotor recovery in any of the treatment groups including controls. Immunohistochemistry assessment indicated positive labeling of P75 and S100 markers in the cell-transplanted groups compared with control. Our data suggest that transplantation of Schwann cells and/or olfactory ensheathing cells into the subarachnoid space does not improve motor recovery in severely injured spinal cord, at least with the number of cells transplanted here. This, however, should not be regarded as an essentially negative outcome, and further studies which consider higher densities of cells are required.
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Células de Schwann/trasplante , Traumatismos de la Médula Espinal/terapia , Espacio Subaracnoideo/citología , Animales , Células Cultivadas , Femenino , Ratas , Ratas Wistar , Recuperación de la FunciónRESUMEN
Background Extraneural scar formation is a challenging problem in nerve repair. Rodent models of scar induction, with their high regenerative capacity, suffer from lack of comparable similarities with human cases. In this study, we attempted to find a reliable and reproducible method of extraneural scarring with a significant impact on the peripheral nerve function. Methods A total of 60 rats were divided into three scar induction groups: abrasion (with a small piece of compressed steel wool), mincing (with extracorporeal mincing of adductor muscle and a 5-mm wide strip of the anterior border of the biceps femoris), and electrocoagulation (with a bipolar coagulator). Extraneural scarring was evaluated macroscopically and histologically during 8 weeks. The tibial functional index was used for behavioral analysis. Results Among three different physical methods of scar induction that were applied, electrocoagulation had the most functional impairment (p < 0.001, two-way analysis of variance); whereas mincing produced the most adhesive and intensive scar, morphologically (p < 0.001). Conclusion We conclude that: (1) the impact of the extraneural scar on the nerve is morphologically and functionally different, based on the method of scarring; (2) to achieve a scar model comparable to the human situation, a method in which the involved nerve is functionally impaired, is preferred over the ones that merely produce a bulky scar.
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Cicatriz/patología , Miembro Posterior/patología , Traumatismos de los Nervios Periféricos/patología , Nervios Periféricos/patología , Animales , Modelos Animales de Enfermedad , Femenino , Miembro Posterior/irrigación sanguínea , Neovascularización Fisiológica , Complicaciones Posoperatorias , Ratas , Cicatrización de HeridasRESUMEN
In this study, we report the apoptosis induction in HER2 overexpressed breast cancer cells using pulsed, continuous wave lasers and polyvinylpyrrolidone (PVP)-stabilized magneto-plasmonic nanoshells (PVP-MPNS) delivered by immunoliposomes. The immunoliposomes containing PVP-MPNS were fabricated and characterized. Heating efficiency of the synthesized nanostructures was calculated. The effect of functionalization on cellular uptake of nanoparticles was assessed using two cell lines of BT-474 and Calu-6. The best uptake result was achieved by functionalized liposome (MPNS-LAb) and BT-474. Also, the interaction of 514 nm argon (Ar) and Nd/YAG second harmonic 532-nm lasers with nanoparticles was investigated based on the temperature rise of the nanoshell suspension and the release value of 5(6)-carboxyfluorescein (CF) from CF/MPNS-loaded liposomes. The temperature increase of the suspensions after ten consecutive pulses of 532 nm and 5 min of irradiation by Ar laser were measured approximately 2 and 12 °C, respectively. The irradiation of CF/MPNS-loaded liposomes by Ar laser for 3 min resulted in 24.3 % release of CF, and in the case of 532 nm laser, the release was laser energy dependent. Furthermore, the comparison of CF release showed a higher efficiency for the Ar laser than by direct heating of nanoshell suspension using circulating water. The percentage of cell apoptosis after irradiation by Ar and 532 nm lasers were 44.6 and 42.6 %, respectively. The obtained results suggest that controlling the NP-laser interaction using optical properties of nanoshells and the laser parameters can be used to develop a new cancer therapy modality via targeted nanoshell and drug delivery.
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Neoplasias de la Mama/terapia , Láseres de Estado Sólido/uso terapéutico , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Química Farmacéutica , Femenino , Fluoresceínas/metabolismo , Colorantes Fluorescentes/metabolismo , Humanos , Hipertermia Inducida , Liposomas , Nanocáscaras/química , Nanocáscaras/ultraestructura , Fotoquimioterapia , Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/farmacología , Povidona/química , Receptor ErbB-2/metabolismo , Trastuzumab/química , Trastuzumab/farmacologíaRESUMEN
BACKGROUND: Peripheral nerve repair outcomes are suboptimal in the presence of severe soft tissue injury and excessive scarring paralleling the process in tendon reconstruction of the hand. Inspired by the advantages of the two-stage technique in tendon grafting and with encouraging preliminary results, we aimed to investigate the two-stage nerve grafting technique as an alternative method of secondary nerve repair. METHODS: Thirty female rats (~200 g) were randomly distributed into two groups (n=15). A 15 mm gap was created in the sciatic nerve of the animals and an excessive extraneural scar was induced using the "mincing" method. In this method, a thin strip of muscle was removed, minced in a petri dish and returned to the peripheral nerve. In the two-stage nerve graft group, a silicone tube was interposed in the first stage. After 4 weeks, in the second stage, the silicone tube was removed and a median nerve autograft was interposed through the newly formed vascularized sheath. In the conventional graft group, two nerve ends were protected with silicone caps in the first stage. After 4 weeks the caps were removed and the median graft was interposed. Behavioral assessments were performed at week 15 after surgery with the withdrawal reflex latency (WRL) and extensor postural thrust (EPT) and at the 3, 6 and 15-week time points with the TOA (toe out angle). Masson Trichrome staining method was used for histological assessments at week 15. RESULTS: According to the EPT and WRL, the two-stage nerve graft showed significant improvement (P=0.020 and P=0.017 respectively). The TOA showed no significant difference between the two groups. The total vascular index was significantly higher in the two-stage nerve graft group (P<0.001). CONCLUSIONS: Two-stage nerve graft using a silicone tube enhances vascularity of the graft and improves functional recovery.
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Denervation of the hind limb is a technique used to study peripheral nerve regeneration. Autotomy or autophagia is an undesirable response to denervation in such studies. Application of a commercially available lotion used to deter nail biting in humans reduced autotomy in rats after denervation but did not completely prevent it. In this study, this authors evaluated the application of picric acid to prevent autotomy in rats in peripheral nerve experiments. They carried out sciatic nerve transection in 41 adult female Wistar rats and then applied either bite-deterrent lotion (n = 26) or saturated picric acid solution (n = 15) topically to the affected hind limb immediately after surgery and every day for 1 month. Autotomy scores were lower for rats treated with picric acid than for rats treated with bite-deterrent lotion 1 week and 2 weeks after surgery but were not different between the two groups 4 weeks after surgery. The authors conclude that application of picric acid could be used as an alternative strategy to prevent autotomy in peripheral nerve studies.
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Desnervación/efectos adversos , Picratos/farmacología , Compuestos de Amonio Cuaternario/farmacología , Automutilación/prevención & control , Administración Tópica , Animales , Femenino , Miembro Posterior/cirugía , Ratas , Ratas Wistar , Nervio Ciático/cirugía , Crema para la Piel/farmacologíaRESUMEN
OBJECTIVE: The use of fibrin adhesives has a broad background in nerve repair. Currently the suboptimal physical properties of single- donor fibrin adhesives have restricted their usage. The present experiment studies the performance and physical characteristics of a modified fibrin glue prepared from single-donor human plasma in the repair of posterior tibial nerve of rat. METHODS: Forty Wistar rats were divided into 5 groups; in the control group, tibial nerve was completely transected and no treatment was done, while in the four experimental groups the nerve stumps were reconnected by one suture, three sutures, one suture with fibrin glue and fibrin glue alone respectively. During 8 weeks of follow-up, Tibial Function Index was measured weekly and adhesive strength, inflammation and scar formation were assessed at the end of the study. RESULTS: Nerve stumps dehiscence rate and adhesive strength were similar in all experimental groups and significantly differed from control group (P<0.05). By the end of the eighth follow-up week, functional recovery of one and three sutures groups were significantly higher than groups in which fibrin glue was used for repair (P<0.05). The amount of inflammation and scar tissue formation was similar among all groups. CONCLUSION: The study results show that the prepared single-donor fibrin adhesive has acceptable mechanical properties which could provide required adhesiveness and hold nerve stumps in the long term; yet, we acknowledge that more studies are needed to improve functional outcome of single donor fibrin adhesive repair.
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Adhesivo de Tejido de Fibrina/uso terapéutico , Nervio Tibial/cirugía , Animales , Humanos , Regeneración Nerviosa , Ratas , Ratas WistarRESUMEN
UNLABELLED: Objective (s): Scar formation in injured peripheral nerve bed causes several consequences which impede the process of nerve regeneration. Several animal models are used for scar induction in preclinical studies which target prevention and/or suppression of perineural scar. This study evaluates the translational capacity of four of physical injury models to induce scar formation around the sciatic nerve of rat: laceration, crush, mince and burn. MATERIALS AND METHODS: Functional (Toe out angle), macroscopic, and microscopic evaluations were performed weekly for four weeks and correlation of findings were analyzed. RESULT: While macroscopic and microscopic findings suggested a well-developed and adhesive fibrosis surrounding the sciatic nerve, functional assessment did not reveal any significant difference between control and experimental groups (P>0.05). CONCLUSION: Our study suggests that none of the applied animal models reproduce all essential features of clinical perineural scar formation. Therefore, more studies are needed to develop optimal animal models for translating preclinical investigations.
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Prior animal models have shown that rats sustaining 3-second immediate spinal cord compression had significantly better functional recovery and smaller lesion volumes than rats subjected to compression times of 1 hour, 6 hours, 3 weeks, and 10 weeks after spinal cord injury. We compare locomotor rating scales and spinal cord histopathology after 3 seconds and 10 minute compression times. . Ten rats were assigned into two early (3-second) and late (10-minute) compressive surgery groups. Compressive injury was produced using an aneurysmal clip method. Rats were followed-up for 11 weeks, and behavioral assessment was done by inclined plane test and tail-flick reflex. At the end of the study, the rats were sacrificed, and spinal cord specimens were studied in light and EM. Basso, Beattie and Bresnahan (BBB) locomotor rating scales were significantly better in the early compression group after the 4th week of evaluation (P<0.05) and persisted throughout the remainder of the study. Histopathology demonstrated decreased normal tissue, more severe gliosis and cystic formation in the late group compared to the early group (P<0.05). In EM study, injuries in the late group including injury to the myelin and axon were more severe than the early compression group, and there was more cytoplasmic edema in the late compression group. Spinal cord injury secondary to 3-second compression improves functional motor recovery, spares more functional tissue, and is associated with less intracellular edema, less myelin and axon damage and more myelin regeneration in rats compared to those with 10 minutes of compression. Inclined plane test and tail-flick reflex had no significant difference.
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Descompresión Quirúrgica , Compresión de la Médula Espinal/cirugía , Animales , Modelos Animales de Enfermedad , Femenino , Microscopía Electrónica , Actividad Motora , Regeneración Nerviosa , Ratas , Compresión de la Médula Espinal/patología , Compresión de la Médula Espinal/fisiopatología , Factores de TiempoRESUMEN
OBJECT: Many experimental studies on spinal cord injuries (SCIs) support behavioral improvement after Schwann cell treatment. This study was conducted to evaluate safety issues 2 years after intramedullary Schwann cell transplantation in 33 consecutively selected patients with SCI. METHODS: Of 356 patients with SCIs who had completed at least 6 months of a conventional rehabilitation program and who were screened for the study criteria, 33 were enrolled. After giving their informed consent, they volunteered for participation. They underwent sural nerve harvesting and intramedullary injection of a processed Schwann cell solution. Outcome assessments included a general health questionnaire, neurological examination, and functional recordings in terms of American Spinal Injury Association (ASIA) and Functional Independence Measure scoring, which were documented by independent observers. There were 24 patients with thoracic and 9 with cervical injuries. Sixteen patients were categorized in ASIA Grade A, and the 17 remaining participants had ASIA Grade B. RESULTS: There were no cases of deep infection, and the follow-up MR imaging studies obtained at 2 years did not reveal any deformity related to the procedure. There was no case of permanent neurological worsening or any infectious or viral complications. No new increment in syrinx size or abnormal tissue and/or tumor formation were observed on contrast-enhanced MR imaging studies performed 2 years after the treatment. CONCLUSIONS: Preliminary results, especially in terms of safety, seem to be promising, paving the way for future cell therapy trials.
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Trasplante de Células/efectos adversos , Células de Schwann/trasplante , Traumatismos de la Médula Espinal/terapia , Adulto , Trasplante de Células/métodos , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Examen Neurológico , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/rehabilitación , Resultado del TratamientoRESUMEN
The p75 pan-neurotrophin receptor (p75(NTR)) plays a pivotal role in linking the immune system with the nervous system. p75(NTR) is required for the development of several characteristic features of allergic asthma. Also p75(NTR) upregulated by reactive Schwann cells after peripheral nerve injury. Moreover p75(NTR) and RhoA play a critical role in the regulation of apoptosis. To determine whether the designed siRNA for p75(NTR) can downregulates both p75(NTR) and Rho-A at RNA level in rats and, if so, at what magnitude, Schwann cell apoptosis occurs. Isolation and purification of neonate Schwann cells were prepared from rat sciatic nerve. Specific siRNA duplex was designed for p75(NTR) . To investigate the role of siRNA-mediated knockdown of p75(NTR) , the gene expression in p75(NTR) was examined with reverse transcription-polymerase chain reaction (RT-PCR) and Real-Time RT-PCR. Schwann cell apoptosis was performed by Annexin and TUNEL assays after 24 hours. Following p75(NTR) Transfection siRNA, p75(NTR) gene, compared with control, was downregulated by 73%. Without using siRNA for Rho-A, Rho-A gene was downregulated by 89% at the same time. Based on Annexin assay, apoptosis of Schwann cells occurred in siRNA+NGF and control+NGF by 16.76%±2.27 and 92.39%±1.82, respectively. TUNEL data showed that apoptosis of Schwann cells occurred in siRNA and control by 12.91%±6.39 and 78.55%±11.85, respectively. Thus, p75-siRNA downregulated both p75(NTR) and Rho-A at RNA level in rats and showed a role on decreased cell apoptosis compared to the controls.