Ultrasound Stimulation Inhibits Morphological Degeneration of Motor Endplates in the Denervated Skeletal Muscle of Rats

Recovery of motor function after peripheral nerve injury requires treatment of the neuromuscular junction (NMJ), as well as the injured nerve and skeletal muscle. The purpose of this study was to examine the effects of ultrasound (US) stimulation on NMJ degeneration after denervation using a rat model of peroneal nerve transection. Twelve-week-old male Wistar rats were randomly assigned to 3 groups: US stimulation, sham stimulation, and intact. US or sham stimulation was performed on the left tibialis anterior (TA) muscle starting the day after peroneal nerve transection for 5 minutes daily under anesthesia. Four weeks later, the number and morphology of the motor endplates were analyzed to assess NMJ in the TA muscle. The endplates were classified as normal, partially fragmented, or fully fragmented for morphometric analysis. In addition, the number of terminal Schwann cells (tSCs) per endplate and percentage of endplates with tSCs (tSC retention percentage) were calculated to evaluate the effect of tSCs on NMJs. Our results showed that endplates degenerated 4 weeks after transection, with a decrease in the normal type and an increase in the fully fragmented type in both the US and sham groups compared to the intact group. Furthermore, the US group showed significant suppression of the normal type decrease and a fully fragmented type increase compared to the sham group. These results suggest that US stimulation inhibits endplate degeneration in denervated TA muscles. In contrast, the number of endplates and tSC and tSC retention percentages were not significantly different between the US and sham groups. Further investigations are required to determine the molecular mechanisms by which US stimulation suppresses degeneration

Regenerative Rehabilitation for Stroke Recovery by Inducing Synergistic Effects of Cell Therapy and Neurorehabilitation on Motor Function: A Narrative Review of Pre-Clinical Studies

Neurological diseases severely affect the quality of life of patients. Although existing treatments including rehabilitative therapy aim to facilitate the recovery of motor function, achieving complete recovery remains a challenge. In recent years, regenerative therapy has been considered as a potential candidate that could yield complete functional recovery. However, to achieve desirable results, integration of transplanted cells into neural networks and generation of appropriate microenvironments are essential. Furthermore, considering the nascent state of research in this area, we must understand certain aspects about regenerative therapy, including specific effects, nature of interaction when administered in combination with rehabilitative therapy (regenerative rehabilitation), and optimal conditions. Herein, we review the current status of research in the field of regenerative therapy, discuss the findings that could hold the key to resolving the challenges associated with regenerative rehabilitation, and outline the challenges to be addressed with future studies. The current state of research emphasizes the importance of determining the independent effect of regenerative and rehabilitative therapies before exploring their combined effects. Furthermore, the current review highlights the progression in the treatment perspective from a state of compensation of lost function to that of a possibility of complete functional recovery

Effects of in vivo cyclic compressive loading on the distribution of local Col2 and superficial lubricin in rat knee cartilage

This study aimed to examine the effects of an episode of in vivo cyclic loading on rat knee articular cartilage (AC) under medium-term observation, while also investigating relevant factors associated with the progression of post-traumatic osteoarthritis (PTOA). Twelve-week-old Wistar rats underwent one episode comprising 60 cycles of 20 N or 50 N dynamic compression on the right knee joint. Spatiotemporal changes in the AC after loading were evaluated using histology and immunohistochemistry at 3 days and 1, 2, 4, and 8 weeks after loading (n = 6 for each condition). Chondrocyte vitality was assessed at 1, 3, 6, and 12 hours after loading (n = 2 for each condition). A localized AC lesion on the lateral femoral condyle was confirmed in all subjects. The surface and intermediate cartilage in the affected area degenerated after loading, but the calcified cartilage remained intact. Expression of type II collagen in the lesion cartilage was upregulated after loading, whereas the superficial lubricin layer was eroded in response to cyclic compression. However, the distribution of superficial lubricin gradually recovered to the normal level 4 weeks after loading-induced injury. We confirmed that 60 repetitions of cyclic loading exceeding 20 N could result in cartilage damage in the rat knee. Endogenous repairs in well-structured joints work well to rebuild protective layers on the lesion cartilage surface, which may be the latent factor delaying the progression of PTOA

Holes in the valence band of superconducting boron-doped diamond film studied by soft X-ray absorption and emission spectroscopy

Carbon- and boron-2$p$ states of superconducting and non-superconducting boron-doped diamond samples are measured using soft X-ray emission and absorption spectroscopy. For the superconducting sample, a large density of hole states is observed in the valence band in addition to the states in the impurity band. The hole states in the valence band is located at about 1.3 eV below the valence band maximum regardless of the doping level, which cannot be interpreted within a simple rigid band model. Present experimental results, combined with the first principles calculations, suggest that superconductivity is to be attributed to the holes in the valence band.Comment: 4 pages, 4 figure

Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO1−x_{1-x}Fx_x}

For a newly discovered iron-based high $T_c$ superconductor LaFeAsO$_{1-x}$F$_x$, we have constructed a minimal model, where inclusion of all the five Fe $d$ bands is found to be necessary. Random-phase approximation is applied to the model to investigate the origin of superconductivity. We conclude that the multiple spin fluctuation modes arising from the nesting across the disconnected Fermi surfaces realize an extended s-wave pairing, while d-wave pairing can also be another candidate.Comment: 5 pages, 2 figures, to be published in Phys. Rev. Let

Culture temperature affects human chondrocyte messenger RNA expression in monolayer and pellet culture systems

Cell-based therapy has been explored for articular cartilage regeneration. Autologous chondrocyte implantation is a promising cell-based technique for repairing articular cartilage defects. However, there are several issues such as chondrocyte de-differentiation. While numerous studies have been designed to overcome some of these issues, only a few have focused on the thermal environment that can affect chondrocyte metabolism and phenotype. In this study, the effects of different culture temperatures on human chondrocyte metabolism- and phenotype-related gene expression were investigated in 2D and 3D environments. Human chondrocytes were cultured in a monolayer or in a pellet culture system at three different culture temperatures (32° C, 37° C, and 41° C) for 3 days. The results showed that the total RNA level, normalized to the threshold cycle value of internal reference genes, was higher at lower temperatures in both culture systems. Glyceraldehyde-3- phosphate dehydrogenase (GAPDH) and citrate synthase (CS), which are involved in glycolysis and the citric acid cycle, respectively, were expressed at similar levels at 32° C and 37° C in pellet cultures, but the levels were significantly lower at 41° C. Expression of the chondrogenic markers, collagen type IIA1 (COL2A1) and aggrecan (ACAN), was higher at 37° C than at 32° C and 41° C in both culture systems. However, this phenomenon did not coincide with SRY (sex-determining region Y)-box 9 (SOX9), which is a fundamental transcription factor for chondrogenesis, indicating that a SOX9-independent pathway might be involved in this phenomenon. In conclusion, the expression of chondrocyte metabolism-related genes at 32° C was maintained or enhanced compared to that at 37° C. However, chondrogenesis-related genes were further induced at 37° C in both culture systems. Therefore, manipulating the culture temperature may be an advantageous approach for regulating human chondrocyte metabolic activity and chondrogenesis