Histomorphometric study of the soleus muscle under conditions of modeling of spinal cord contusion injury: experimental morphological study

Objective. To conduct a morphometric analysis of the soleus muscle of rats after moderate spinal cord contusion injury.Material and Methods. Experiments were performed on female Wistar rats aged 8–12 months, weighing 270–320 g. Animals of the experimental group (n = 25) underwent laminectomy at the T9 level under general anesthesia and modeling of spinal contusion injury of moderate severity. Intact rats constituted the control group (n = 10). Euthanasia was performed on the 5th, 15th, 30th, 60th, 90th, and 180th days of the experiment. Paraffin sections were stained with hematoxylin-eosin and Masson, the diameters of muscle fibers were determined by computer morphometry, and histograms of their distribution were obtained.Results. In the soleus muscle, the signs of reversible reparative processes prevailed in response to neurotrophic damage. It was evidenced by a local increase in the diversity of myocyte diameters and the loss of polygonality of their profiles, focal destruction of muscle fibers, activation of the connective tissue component, disorganization of some intramuscular nerve conductors, and vascular fibrosis of perimysium. Nevertheless, the histostructure of an intact muscle prevailed in the course of the experiment, which was confirmed by the data of morphometric analysis. All histograms of the distribution of the muscle fiber diameters are unimodal with a mode in the range of 30–41 μm. On the 180th day, the maximum myocyte diameters in the histogram of the left limb muscle belonged to the range of 21–30 μm, which was typical for histograms in the intact group.Conclusion. The nature of the plastic reorganization of the soleus muscle when neurotrophic control is impaired indicates compensatory regeneration of muscle tissue by the type of restitution, which opens up the possibility of predicting the rehabilitation period. It is advisable to take this into account when developing medical and social programs and therapeutic measures, where the most important role is played by superficial neuromuscular and functional electrical stimulation.

Diagnosis and Simultaneous Treatment of Musculoskeletal Injury Using H2O2-Triggered Echogenic Antioxidant Polymer Nanoparticles in a Rat Model of Contusion Injury

Ultrasound is clinically used for diagnosis and interventions for musculoskeletal injuries like muscle contusion, but contrast of ultrasonography still remains a challenge in the field of the musculoskeletal system. A level of hydrogen peroxide (H2O2) is known to be elevated during mechanical tissue damage and therefore H2O2 can be exploited as a diagnostic and therapeutic marker for mechanical injuries in the musculoskeletal system. We previously developed poly(vanillin-oxalate) (PVO) as an inflammation-responsive polymeric prodrug of vanillin, which is designed to rapidly respond to H2O2 and exert antioxidant and anti-inflammatory activities. The primary aim of this study is to verify whether PVO nanoparticles could serve as contrast agents as well as therapeutic agents for musculoskeletal injuries simultaneously. In a rat model of contusion-induced muscle injury, PVO nanoparticles generated CO2 bubbles to enhance the ultrasound contrast in the injury site. A single intramuscular injection of PVO nanoparticles also suppressed contusion-induced muscle damages by inhibiting the expression of pro-inflammatory cytokines and inflammatory cell infiltration. We, therefore, anticipate that PVO nanoparticles have great translational potential as not only ultrasound imaging agents but also therapeutic agents for the musculoskeletal disorders such as contusion.

Morphological changes in the sciatic nerve in experimental modeling of contusion injury of the spinal cord in rats

Objective. To analyze morphological and morphometric changes in the sciatic nerve of rats after the spinal cord injury.Material and Methods. The Т9 moderately severe contusion injury of the spinal cord was simulated in 12 Wistar female rats. Functions of the pelvic limbs were assessed according to the standardized BBB scale. The animals were withdrawn from the experiment after nine and 13 weeks. Epoxy semi-thin (1 µm) sections were used to study sciatic nerve at the light-optical level.Results. Significant recovery of pelvic limb functions was observed within four weeks after surgery, the plateau was achieved by Week 5 (9.5 ± 0.28 points according to the BBB scale), the deterioration in the motor activity was observed by Week 9 (8.67 ± 0.33), its recovery was achieved by Week 13 of the experiment (9.5 ± 0.87). After 9 and 13 weeks, reactive-destructive changes were detected in the sciatic nerve in 9 % and 8 % of nerve conductors, an increase in the number density of myelin fibers by 28 % and 27 % (p < 0.05) and myelin-free fibers by 20 % and 49 % (p < 0.05), and a decrease in axon diameters by 8 % and 10 % (p < 0.05), respectively.Conclusions. The morphological and morphometric changes in the sciatic nerve revealed after the spinal cord injury in the form of destruction of a part of the fibers, axonal atrophy and a decrease in the proportion of large fibers negatively affect its conductive properties. The leveling of peripheral nerve damage, possibly, will accelerate the regression of the motor deficit caused by the spinal cord injury; therefore, it is necessary to develop a set of preventive measures aimed at preventing the reorganization of the peripheral nerve tissue.

Spinal Cord Injury Causes Reduction of Galanin and Gastrin Releasing Peptide mRNA Expression in the Spinal Ejaculation Generator of Male Rats

Spinal cord injury (SCI) in men is commonly associated with sexual dysfunction, including anejaculation, and chronic mid-thoracic contusion injury in male rats also impairs ejaculatory reflexes. Ejaculation is controlled by a spinal ejaculation generator consisting of a population of lumbar spinothalamic (LSt) neurons that control ejaculation through release of four neuropeptides including galanin and gastrin releasing peptide (GRP) onto lumbar and sacral autonomic and motor nuclei. It was recently demonstrated that spinal contusion injury in male rats caused reduction of GRP-immunoreactivity, but not galanin-immunoreactivity in LSt cells, indicative of reduced GRP peptide levels, but inconclusive results for galanin. The current study further tests the hypothesis that contusion injury causes a disruption of GRP and galanin mRNA in LSt cells. Male rats received mid-thoracic contusion injury and galanin and GRP mRNA were visualized 8 weeks later in the lumbar spinal cord using fluorescent in situ hybridization. Spinal cord injury significantly reduced GRP and galanin mRNA in LSt cells. Galanin expression was higher in LSt cells compared to GRP. However, expression of the two transcripts were positively correlated in LSt cells in both sham and SCI animals, suggesting that expression for the two neuropeptides may be co-regulated. Immunofluorescent visualization of galanin and GRP peptides demonstrated a significant reduction in GRP-immunoreactivity, but not galanin in LSt cells, confirming the previous observations. In conclusion, SCI reduced GRP and galanin expression in LSt cells with an apparent greater impact on GRP peptide levels. GRP and galanin are both essential for triggering ejaculation and thus such reduction may contribute to ejaculatory dysfunction following SCI in rats.

Organization and implementation of emergency ophthalmic surgical assistance in a specialized ophthalmic clinic during the Pandemic period COVID-19

Purpose. Evaluation of the frequency, structure and severity of the eye injuries, the effectiveness of the implementation of primary surgical treatment (PST) and the outcomes of their surgical treatment. Material and methods. In just a period from the end of March to December 2020, in the Khabarovsk branch the S. Fyodorov Eye Microsurgery Federal State Institution received 51 patients with various as penetrating (48 eyes) and imperriburing injuries of the eyeball (3 eyes). Their age varied widespread from 5 to 56 years (on average 35.5 years). Men were dominated among them – 44 people, women – 7 people. Adults were 49 people, children – 2 people. Results. Under the conditions of obtaining penetrating injuries, household injuries were isolated – 33 eyes (65%), production – 15 eyes (29%). The contusion injury of the eye was criminal, which was 6% (3 eyes). According to the localization of penetrating injuries or the impact of mechanical damage, they were presented: corneal wounds – 12 eyes, rootless – 17 eyes, scleral – 18 eyes. In 13 eyes, there was an intraocular foreign bodies (IFB). Conclusion. Thus, for the period from April to December 2020, in our branch, PST eyes were performed about 47 heavy penetrating injuries, including the introduction of IFB in 13 eyes, 4 eyes with extensive damage to conjunctiva. Among the victims were 49 adults and 2 children. Key words: penetrating eye wound, intraocular foreign body, microgery surgery, traumatic retinal detachment.

Microglia Stimulation by Protein Extract of Injured Rat Spinal Cord. A Novel In vitro Model for Studying Activated Microglia

Research on microglia has established the differentiation between the so-called M1 and M2 phenotypes. However, new frameworks have been proposed attempting to discern between meaningful microglia profiles. We have set up an in vitro microglial activation model by adding an injured spinal cord (SCI) lysate to microglial cultures, obtained from postnatal rats, in order to mimic the environment of the spinal cord after injury. We found that under the presence of the SCI lysate microglial cells changed their phenotype, developing less ramified but longer processes, and proliferated. The SCI lysate also led to upregulation of pro-inflammatory cytokines, such as IL-1β, IL-6, and TNF-α, downregulation of the anti-inflammatory cytokines IL-10 and IL-4, and a biphasic profile of iNOS. In addition, a latex beads phagocytosis assay revealed the SCI lysate stimulated the phagocytic capacity of microglia. Flow cytometry analysis indicated that microglial cells showed a pro-inflammatory profile in the presence of SCI lysate. Finally, characterization of the microglial activation in the spinal cord on day 7 after contusion injury, we showed that these cells have a pro-inflammatory phenotype. Overall, these results indicate that the use of SCI lysates could be a useful tool to skew microglia towards a closer phenotype to that observed after the spinal cord contusion injury than the use of LPS or IFNγ.

Multiple and early hyperbaric oxygen treatments enhance muscle healing after muscle contusion injury: a pilot study

Background: The optimal timing of hyperbaric oxygen (HBO2) treatments for the best recovery following muscle injury has yet to be determined. Thus, the optimal number and timing of HBO2 treatments for maximal muscle regeneration were explored. Methods: The HBO2 treatment protocol consisted of 2.5 ATA 100% oxygen for 120 minutes. Muscle-injured rats were randomized to one of 10 groups: single HBO2 treatment immediately after injury (HBO 1T day 0), one day (HBO 1T day 1), three days (HBO 1T day 3) and five days (HBO 1T day 5) after injury; three HBO2 treatments from immediately after injury to two days after injury (HBO 3T day 0-2), from one to three days after injury (HBO 3T day 1-3), from three to five days after injury (HBO 3T day 3-5), from five to seven days after injury (HBO 3T day 5-7); five daily HBO2 treatments (HBO 5T); and no treatment (NT). Results: HBO 5T and HBO 3T day 0-2, days 1-3 and days 3-5 significantly promoted CD206-positive cell infiltration, satellite cell differentiation and muscle regeneration compared to the NT group. Conclusion: Five HBO2 treatments and three HBO2 treatments within three days of injury promote muscle regeneration.