Experimental unilateral intracerebral hemorrhage induces delayed bilateral neurodegeneration of sciatic nerve fibres in rats.

Pathological processes, such as inflammatory effects, oxidative stress, apoptosis and cytotoxicity of blood after an intracerebral hemorrhage (ICH), generally contribute to a secondary injury. One of the secondary ICH consequences in the nervous system may be delayed neurodegeneration of the peripheral nerves. Therefore, the aim of our study was to investigate possible structural changes in the sciatic nerve and changes in the conduction velocity via this nerve at different terms after experimental ICH in male Wistar rats. Intracerebral hemorrhage was provided by direct injection of autologous blood into the capsula interna. On the 10th day after ICH mean conduction velocity in sciatic nerve was 15% smaller compared to the control. On the 30th and 90th days after ICH, highly significant decreases in the conduction velocity by 62% and 60%, respectively in comparison with the control group of animals were observed. The data of morphometric analysis demonstrated significant decreases in the mean diameter and density of myelinated fibres at all examined terms after ICH. A number of the myelin sheaths were swollen and lost their regular laminations. Axoplasmic and myelin degenerations were the most frequent events in these nerve fibres; reductions of the diameter of the axis cylinders were also observed. In the contralateral nerve (related to the hemisphere with ICH), negative changes were greater, while the ipsilateral nerve was also subjected to those. Our data demonstrate that the consequences of unilateral ICH in the capsula interna induce bilateral negative changes in the peripheral nervous system of rats.

Quantitative evaluation of the regenerated dura mater in a decompressive skull trepanation model in rats / Evaluación cuantitativa de la duramadre regenerada en un modelo de perforación cranial descompresiva en ratas

SUMMARY: Regeneration of the dura mater following duraplasty using a collagen film, a chitosan film, or a combination of both with gelatin, was studied in a craniotomy and penetrating brain injury model in rats. Collagen autofluorescence in the regenerated dura mater was evaluated using confocal microscopy with excitation at λem = 488 nm and λem = 543 nm. An increase in regeneration of the extracellular matrix of connective tissue and an increase in matrix fluorescence were detected at 6 weeks after duraplasty. The major contributors to dura mater regeneration were collagen films, chitosan plus gelatin-based films, and, to a much lesser extent, chitosan-based films. By using autofluorescence densitometry of extracellular matrix, the authors were able to quantify the degree of connective tissue regeneration in the dura mater following duraplasty.

RESUMEN: Se estudió la regeneración de la duramadre después de una duraplastía utilizando una lámina de colágeno, una lamina de quitosano o una combinación de ambas con gelatina en un modelo de craneotomía y lesión cerebral en ratas. La autofluorescencia del colágeno en la duramadre regenerada se evaluó mediante microscopía confocal con excitación a λem = 488 nm y λem = 543 nm. Se observó un aumento en la regeneración de la matriz extracelular del tejido conectivo y un aumento en la fluorescencia de la matriz a las 6 semanas después de la duraplastía. Se observe un efecto significativo en la regeneración de la duramadre con las láminas de colágeno, las láminas en base de quitosano más gelatina y, en un menor grado, las láminas a base de quitosano. Mediante el uso de densitometría de autofluorescencia de la matriz extracelular, los autores lograron cuantificar el grado de regenera- ción del tejido conectivo en la duramadre después de la duraplastía.

The efficacy of immediate implantation of macroporous poly(N-[2-hydroxypropyl]-methacrylamide) hydrogel after laceration spinal cord injury in young rats / Eficacia de la implantación inmediata de hidrogel macroporoso de poli (N- [2-hidroxipropil] - metacrilamida) después de una lesión de la médula espinal en ratas jóvenes

SUMMARY: Spinal cord regeneration after mechanical injury is one of the most difficult biomedical problems. This article evaluates the effect of poly(N-[2-hydroxypropyl]-methacrylamide) hydrogel (PHPMA-hydrogel) on spinal cord regeneration in young rats after lateral spinal cord hemi-excision (laceration) at the level of segments T12-T13 (TrGel group). The locomotor function score (FS) and the paretic hindlimb spasticity score (SS) were assessed according to Basso-Beattie-Bresnahan (BBB) and Ashworth scales, respectively, and compared to a group of animals with no matrix implanted (Tr group). Regeneration of nerve fibers at the level of injury was evaluated at ~5 months after spinal cord injury (SCI). One week after the SCI induction, the FS on the BBB scale was 0.9±0.5 points in the Tr group and 3.6±1.2 points in the TrGel group. In the Tr group, the FS in 5 months was significantly lower than in 2 weeks after SCI, while no significant changes in FS were detected in the TrGel group over the entire observation period. The final FS was 0.8±0.3 points in the Tr group and 4.5±1.8 points in the TrGel group. No significant changes in SS have been observed in the TrGel group throughout the experiment, while the Tr group showed significant increases in SS at 2nd week, 6th week, 3th month and 5th month. The SS in 5 months was 3.6±0.3 points on the Ashworth scale in the Tr group and 1.8±0.7 points in the TrGel group. Throughout the observation period, significant differences in FS between groups were observed only in 5 weeks after SCI, whereas significant differences in SS were observed in 2, 3 and 6-8 weeks post-injury. Glial fibrous tissue containing newly formed nerve fibers, isolated or grouped in small clusters, that originated from the surrounding spinal cord matter have been found between the implanted hydrogel fragments. In conclusion, PHPMA-hydrogel improves recovery of the hindlimb locomotor function and promotes regenerative growth of nerve fibers. Further research is needed to clarify the mechanism of this PHPMA-hydrogel effect.

RESUMEN: La regeneración de la médula espinal después de una lesión mecánica es uno de los problemas biomédicos más difíciles. Este artículo evalúa el efecto del hidrogel de poli (N- [2-hidroxipropil] -metacrilamida) (PHPMA-hidrogel) sobre la regeneración de la médula espinal en ratas jóvenes después de la hemiescisión lateral de la médula espinal (lesión) a nivel de los segmentos T12 - T13 (Grupo TrGel). La puntuación de la función locomotora (FS) y la puntuación de espasticidad parética de las patas traseras (SS) se evaluaron de acuerdo con las escalas de Basso- Beattie-Bresnahan (BBB) y Ashworth, respectivamente, y se compararon con un grupo de animales sin matriz implantada (grupo Tr). Se evaluó la regeneración de las fibras nerviosas al nivel de la lesión ~ 5 meses después de la lesión de la médula espinal (LME). Una semana después de la inducción de SCI, el FS en la escala BBB fue 0,9 ± 0,5 puntos en el grupo Tr y 3,6 ± 1,2 puntos en el grupo TrGel. En el grupo Tr, el FS en 5 meses fue significativamente menor que en 2 semanas después de SCI, mientras que no se detectaron cambios significativos en FS en el grupo TrGel durante el período de observación. El FS final fue de 0,8 ± 0,3 puntos en el grupo Tr y de 4,5 ± 1,8 puntos en el grupo TrGel. No se han obser- vado cambios significativos en SS en el grupo TrGel durante el experimento, mientras que el grupo Tr mostró aumentos significativos en SS en la 2ª semana, 6ª semana, 3º mes y 5º mes. La SS en 5 meses fue de 3,6 ± 0,3 puntos en la escala de Ashworth en el grupo Tr y de 1,8 ± 0,7 puntos en el grupo TrGel. A lo largo del período de observación, se observaron diferencias significativas en FS entre los grupos solo en 5 semanas después de la LME, mientras que se observaron diferencias significativas en SS en 2, 3 y 6-8 semanas después de la lesión. Entre los fragmentos de hidrogel implantados se observó tejido fibroso glial que contenía fibras nerviosas recién formadas, aisladas o agrupadas en pequeños grupos, que se originaban a partir de la materia de la médula espinal circundante. En conclusión, PHPMA-hydrogel mejora la recuperación de la función locomotora de las patas traseras y promueve el crecimiento regenerativo de las fibras nerviosas. Se requieren más estudios para aclarar el mecanismo del efecto de hidrogel PHPMA.

The effect of hyaluronic acid on the periodontium in spontaneous periodontitis in rats / El efecto del ácido hialurónico sobre el periodonto en periodontitis espontánea en ratas

SUMMARY: The aim of the article was to study changes in periodontal tissues in rats with spontaneous periodontitis (SP) and to evaluate the effect of hyaluronic acid (HA) on the state of the periodontium. Wistar rats with signs of SP were divided into 6 groups: 1) intact group; 2) intact animals with HA "HD-1,0 MDa"; 3) SP group; 4) SP with HA "S-2,4 MDa"; 5) SP with HA "ST-2,4 MDa"; 6) SP with HA "HD-1,0 MDa". The study of the periodontium rats with SP noted the main structural changes (collagen reduction, resorption of alveolar bone, dilatation and stasis of the vessels of the periodontium, gingival papilla and tooth pulp), which were assessed as moderate. Morphological evidence of inflammation was infiltration of neutrophils into the connective tissue of the gums, without the formation of abscesses. Local administration of HA did not cause additional structural damage in periodontal tissues of rats with SP, but also did not affect changes in the microvascular system of periodontium and tooth pulp, periodontal ligaments, only a tendency to inhibit alveolar bone resorption in rats was noted. One can consider the tendency to improve the condition of periodontal tissues in the group of rats injected with high molecular HA and HA with mannitol (2.4 MDa).

RESUMEN: El objetivo del artículo fue estudiar los cambios en los tejidos periodontales en ratas con periodontitis espontánea (PE) y evaluar el efecto del ácido hialurónico (HA) sobre el estado del periodonto. Las ratas Wistar con signos de PE se dividieron en 6 grupos: 1) grupo intacto; 2) animales intactos con HA "HD-1,0 MDa"; 3) grupo PE; 4) PE con HA "S-2,4 MDa"; 5) PE con HA "ST-2,4 MDa"; 6) PE con HA "HD-1,0 MDa". En las ratas con PS se observaron los principales cambios estructurales (reducción de colágeno, reabsorción del hueso alveolar, dilatación y estasis de los vasos del periodonto, papila gingival y pulpa dentaria), que fueron evaluados como moderados. La evidencia morfológica de inflamación fue la infiltración de neutrófilos en el tejido conectivo de las encías, sin la formación de abscesos. La administración local de HA no causó daño estructural adicional en los tejidos periodontales de las ratas con PE, pero tampoco se produjo cambios en el sistema microvascular del periodonto y en la pulpa dental y ligamentos periodontales.Se observó una tendencia a inhibir la resorción del hueso alveolar. Se puede considerar la tendencia a mejorar el estado de los tejidos periodontales en el grupo de ratas inyectadas con HA de alto peso molecular y HA con manitol (2,4 MDa).

Morphometric study of rat sciatic nerve recovery after three nerve repair techniques: epineural suture, polyethylene glycol hydrogel and fibrin sealant / Estudio morfométrico de la recuperación del nervio ciático de rata después de tres técnicas de reparación nerviosa: sutura epineural, hidrogel de polietilenglicol y sellante de fibrina

SUMMARY: The effectiveness of microsurgical technique has a direct impact on the recovery of the injured peripheral nerve. The aim of our study was to investigate the result of sciatic nerve regeneration in rats after complete neurotomy and after nerve repair techniques including: 1) epineural suture; 2) polyethylene glycol hydrogel (PEG) (DuraSeal); 3) fibrin sealant (Tisseel). The cross-section of distal sciatic nerve was studied at 14th, 30th and 60th days after nerve repair. Morphometry of myelinated nerve fibers in the distal stump of the sciatic nerve was performed. A significant increase in the number of myelinated nerve fibers was found, especially between 14 and 30 days. The density of myelinated nerve fibers in the distal stump at day 60 was significantly higher after using nerve repair technique including PEG and fibrin versus epineural suture (29.2 % and 32.1 % versus 21.5 %, P <0.05), and a higher level of remyelination of nerve fibers observed in the group with PEG. On day 60, complete elimination of PEG and fibrin sealant was not observed, encapsulation was found around the clusters of hydrogel. Thereby, three peripheral nerve repair techniques were equally effective, only with the use of PEG remyelination of nerve fibers was increasing.

RESUMEN: La efectividad de la técnica microquirúrgica tiene un impacto directo en la recuperación del nervio periférico lesionado. El objetivo de nuestro estudio fue investigar el resultado de la regeneración del nervio ciático en ratas después de una neurotomía completa y después de técnicas de reparación nerviosa que incluyeron: 1) sutura epineural; 2) hidrogel de polietilenglicol (PEG) (DuraSeal); 3) sellante de fibrina (Tisseel). La sección transversal del nervio ciático distal se estudió a los 14, 30 y 60 días después de la reparación del nervio. Se realizó la morfometría de fibras nerviosas mielinizadas en el muñón distal del nervio ciático. Se observó un aumento significativo en el número de fibras nerviosas mielinizadas, especialmente entre los 14 y 30 días. La densidad de las fibras nerviosas mielinizadas en el muñón distal en el día 60 fue significativamente mayor después de usar una técnica de reparación nerviosa que incluye PEG y fibrina en comparación con la sutura epineural (29,2 % y 32,1 % versus 21,5 %, P <0,05), y un mayor nivel de remielinización del nervio en fibras observadas en el grupo con PEG. El día 60, no se observó la eliminación completa de PEG y sellador de fibrina, se encontró encapsulación alrededor de los grupos de hidrogel. Por lo tanto, tres técnicas de reparación de nervios periféricos fueron igualmente efectivas, solo que aumentaba la remielinización de fibras nerviosas con PEG.

Reparative regeneration by substitution of bone tissue defects with bioglass, using regeneration technologies / Regeneración reparadora mediante sustitución de defectos del tejido óseo por biovidrio, utilizando tecnologías de regeneración

SUMMARY: Bioactive glass (BG) induces osteogenesis of damaged bone, causing excessive bone formation. This study included a morphological and morphometrical data of the bone tissue regeneration by filling bone defects with BG with autologous native platelet rich plasma (PRP) or fibrin (PRF) and aspirate of bone marrow (ABM). The parameters of newly formed bone in rabbits bone defect were analyzed and compared with terms 4th and 12th week. The groups with ABM-BG, PRF-BG and PRP-BG have shown common tendency: development of newly formed bone tissue, the external contour of the bone has been enlarged; an additional trabecular bone has been formed under the cortical layer, which has often been limited by a solid compact bone from the bone marrow. The induced osteogenesis resulted in the appearance of a significant amount of bone tissue exceeding the original size of the defect. Increased density of the newly formed tissue at the defect level relative to ABM-BG was detected in the PRF-BG group at 12 weeks and PRP-BG at 4 and 12 weeks (p<0.05). In this case, the bone thickness in the substituted defect was greater in the ABM-BG group. The number of newly formed bone tissue in the ABM-BG group at 4 weeks also exceeded the value of the BG group, but the density of such bone did not differ between the groups. That is, ABM-BG stimulated greater trabecular bone formation and fibrous reticular tissue was located in the lacunae between trabeculae. These results indicate that the additional use of tissue technology (ABM, platelet plasma) facilitated osteogenesis, and the newly formed bone tissue was tightly coupled and remodeled to the cortical bone layer in the form of compact bone tissue. PRP, to a greater extent than ABM, promoted the formation of compact bone tissue.

RESUMEN: El vidrio bioactivo (VB) induce la osteogénesis del hueso dañado, provocando una formación excesiva de hueso. Este estudio incluyó datos morfológicos y morfométricos de la regeneración del tejido óseo mediante el llenado de defectos óseos con VB con plasma rico en plaquetas (PRP) nativo autólogo o fibrina (PRF) y aspirado de médula ósea (AMO). Se analizaron los parámetros de hueso recién formado en el defecto óseo de conejos y se compararon a las 4 y 12 semanas. Se observó una tendencia similar en los grupos con AMO-VB, PRF-VB y PRP-VB: el desarrollo de tejido óseo recién formado, aumentó el contorno externo del hueso; formación de un hueso trabecular adicional debajo de la capa cortical, que a menudo ha estado limitada por un hueso sólido compacto de la médula ósea. La osteogénesis inducida dio como resultado la aparición de una cantidad significativa de tejido óseo que excedía el tamaño original del defecto. Se detectó un aumento de la densidad del tejido recién formado a nivel del defecto en relación con AMO-VB en el grupo PRF-VB a las 12 semanas y PRP-VB a las 4 y 12 semanas (p <0,05). En este caso, el grosor óseo en el defecto sustituido fue mayor en el grupo AMO-VB. El número de tejido óseo recién formado en el grupo AMO- VB a las 4 semanas también excedió el valor del grupo VB, pero la densidad de dicho hueso no cambió entre los grupos. Es decir, AMO-VB estimuló una mayor formación de hueso trabecular y se localizó en el tejido reticular fibroso en las lagunas entre trabéculas. Estos resultados indican que el uso adicional de tecnología de tejidos (AMO, plasma plaquetario) facilitó la osteogénesis, y el tejido óseo recién formado se acopló y remodeló estrechamente a la capa de hueso cortical en forma de tejido óseo compacto. El PRP, en mayor medida que el AMO, promovió la formación de tejido óseo compacto.

Ultrastructural features of herpesvirus-induced aortic intima damage in mice fed the high-fat diet.

OBJECTIVE: The aim: To study the effect of a high-fat diet (HFD) on the structural changes in the aortic intima in intact and HSV-1-infected mice using Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). PATIENTS AND METHODS: Materials and methods: In experiments Balb/c mice were infected with the HVS-1 and fed high-fat diet and 12 weeks later aortic ultrastructure was examined by SEM and TEM methods. The animals were subdivided into four experimental groups: 1st group - HSV-1-infected animals; 2nd - animals consuming high-fat diet (HFD); 3rd - infected animals that were subsequently consuming a high-fat diet (HSV / HFD); 4th - animals consuming a high-fat diet that were subsequently infected with HSV-1 (HFD / HSV) (n = 6); and control group - intact animals. RESULTS: Results: HVS-1 impaired ultrastructural changes in aorta greater than high-fat diet and HVS-1 alone (higher density of lipid inclusions in the subendothelial space, necrosis of endothelial cells), and infection of mice after high-fat diet ended 100% mortality. The formation of atheroma in the aortic wall during HFD was not detected, but the initiative manifestations of atherogenesis have been identified and restricted in the aortic intima. These structural changes included lipid inclusions in the subendothelial space, cell damage and destruction, which lead to an increase cellular detritus in the 3rd (HSV / HFD) group. CONCLUSION: Conclusions: HSV infection potentiates the accumulation of lipid inclusions in the aortic intima during a HFD, facilitates infection and contributes to the development of acute infection.

Experimental study of the liver ultrastructure in the presence of infection with herpes simplex virus 1.

OBJECTIVE: Introduction: Understanding of HSV-1liver infection pathogenesis is of great scientific, social and economic significance, since this is one of the main latent infections in population. However reactivation of this infection remains understudied. The aim: This experimental research aimed at studying the ultrastructure changes occurring in the liver in the presence of HSV-1infection. PATIENTS AND METHODS: Materials and methods: Experiments were conducted on 12 BALB/c line mice weighing 18-20 g. They were divided into 2 groups: experimental, and control. Experimental animals were infected with the attenuated HSV-1. On day 40 the animals were withdrawn from the experiment by decapitation. Liver fragments were excised and studied ultramicroscopically. RESULTS: Results: Liver disorders were represented by the focal damage of hepatic lobuli cells. Ultrastructure changes were found both in the microvascular endothelium and hepatocytes. The vascular disorders included swelling of endotheliocytes, their demise and desquamation into the lumen, disruption of the basal lamina integrity and diapedesis of blood cells into the subendothelial space. Finding virions in the endotheliocytes allowed to explain the possible pathway of the infection into the interstitium and hepatocytes via systemic circulation from the primary source of infection. Electron microscopy has not revealed any virions in hepatocytes, with only the following changes: significant cytosole density of the osmiophylic granules, lisosomes and lamellar bodies found. These were considered to be the consequence of the infectious process. Findings of the experimental study enable understanding of the causal relationship between the acute infection and liver damage. CONCLUSION: Conclusions: Ultrastructure changes in the liver of mice infected with HSV-1 were focal, and more rarely diffuse in nature. Non-specific cytopathological changes (swelling of the cytoplasm and reduction of the endoplasmatic reticulum, and mitochondria) were found both in the endotheliocytes of the sinusoid capillaries and hepatocytes. Endotheliocytes of the sinusoid liver capillaries in mice infected with HSV-1 lose their barrier function, which leads to direct and indirect damage of hepatocytes and development of dystrophic changes in the liver.