Objective·To preliminarily investigate the regulatory effect and underlying mechanism of fibroblast growth factor 2(FGF2)on R-spondin 1(Rspo1)expression in CD34+CD81+stromal cells from the mouse colon.Methods·Colonic CD45-CD326-CD31-GP38+CD81+Rspo1-tdTomato+stromal cells were sorted from Rspo1-tdTomato reporter mice by flow cytometry and subsequently cultured in vitro.The expression of surface protein markers was evaluated by flow cytometry after 14 d of culture.qPCR was employed to quantify Rspo1 expression in response to stimulation with FGF2,FGF9,epidermal growth factor(EGF),platelet-derived growth factor-bb(PDGF-bb),insulin-like growth factor 1(IGF1),or hepatocyte growth factor(HGF).RNA sequencing and bioinformatic analyses were used to identify the signaling pathways underlying FGF2-mediated regulation of Rspo1,followed by preliminary validation with pathway-specific inhibitors and qPCR.Results·After 14 d of culture,the sorted colonic stromal cells retained expression of CD34,CD81,and glycoprotein GP38,while remaining negative for other lineages markers CD45,CD326,and CD31.qPCR revealed that 20 ng/mL FGF2 significantly suppressed Rspo1 expression,whereas the other tested growth factors exerted no notable effect.RNA sequencing and bioinformatic analysis indicated that mitogen-activated protein kinase(MAPK)signaling pathway played a key role in the regulatory effect of FGF2 on Rspo1.qPCR further demonstrated that pretreatment with U0126,an inhibitor of mitogen extracellular kinase 1/2(MEK1/2),reversed FGF2-mediated suppression of Rspo1 expression.Conclusion·FGF2 may inhibit Rspo1 expression in mouse colonic CD34+CD81+stromal cells via the MEK1/2-extracellular regulated protein kinase 1/2(ERK1/2)signaling pathway.

Objective·To preliminarily investigate the regulatory effect and underlying mechanism of fibroblast growth factor 2(FGF2)on R-spondin 1(Rspo1)expression in CD34+CD81+stromal cells from the mouse colon.Methods·Colonic CD45-CD326-CD31-GP38+CD81+Rspo1-tdTomato+stromal cells were sorted from Rspo1-tdTomato reporter mice by flow cytometry and subsequently cultured in vitro.The expression of surface protein markers was evaluated by flow cytometry after 14 d of culture.qPCR was employed to quantify Rspo1 expression in response to stimulation with FGF2,FGF9,epidermal growth factor(EGF),platelet-derived growth factor-bb(PDGF-bb),insulin-like growth factor 1(IGF1),or hepatocyte growth factor(HGF).RNA sequencing and bioinformatic analyses were used to identify the signaling pathways underlying FGF2-mediated regulation of Rspo1,followed by preliminary validation with pathway-specific inhibitors and qPCR.Results·After 14 d of culture,the sorted colonic stromal cells retained expression of CD34,CD81,and glycoprotein GP38,while remaining negative for other lineages markers CD45,CD326,and CD31.qPCR revealed that 20 ng/mL FGF2 significantly suppressed Rspo1 expression,whereas the other tested growth factors exerted no notable effect.RNA sequencing and bioinformatic analysis indicated that mitogen-activated protein kinase(MAPK)signaling pathway played a key role in the regulatory effect of FGF2 on Rspo1.qPCR further demonstrated that pretreatment with U0126,an inhibitor of mitogen extracellular kinase 1/2(MEK1/2),reversed FGF2-mediated suppression of Rspo1 expression.Conclusion·FGF2 may inhibit Rspo1 expression in mouse colonic CD34+CD81+stromal cells via the MEK1/2-extracellular regulated protein kinase 1/2(ERK1/2)signaling pathway.

Flash radiotherapy (FLASH-RT) is an advanced radiotherapy technique known for its ultra-high dose rate (>40 Gy/s) irradiation. Preclinical studies have demonstrated that FLASH-RT is highly effective in reducing radiation damage to normal tissues, while still effectively killing tumors. This wider therapeutic window in terms of dose rate makes FLASH-RT a promising and disruptive technique for the future of radiotherapy. However, the biological mechanisms underlying FLASH-RT are not yet fully understood, and there are multiple technical challenges to be addressed before its clinical application. In this article, we provide a brief overview of the recent research progress in FLASH-RT, covering its biological mechanisms, preclinical studies, and the status and challenges in clinical application, aiming to offer valuable reference and inspiration for the future translation of FLASH-RT into clinical practice.

Objective To make sciatic nerve traction injury models of rabbit , in order to prospectively evaluate possibility and accuracy of diffusion tensor tracking (DTT) in sciatic nerve injures. Methods The right sciatic nerves of 32 New Zealand white rabbits were selected for traction injury , and the left sciatic nerves were the sham operation side. DTI scan was performed before and after the operation on 1st day , 3rd day, and 1 week, 2, 3, 4, 6 and 8th week respectively, and DTT was reconstructed. Then the length of reconstructed fiber tracts and fiber density index were calculated. After the MRI scan , the sciatic nerve was removed to perform pathologic examination at different time points. Results The difference of the length of reconstructed fiber tracts between nerve traction injury and sham operation side was significant at 1 day~2weeks after operation (P<0.05), while the difference was not significant at 3~8 weeks.The fiber density index of nerve traction injury and sham operation side was significantly different at 1 day~8 weeks(P<0.05). 1day after operation, myelin sheath of traction portion was obviously twisting. 3 days after operation , a large amount of myelin sheath broke down. 2 weeks after operation , axon, myelin sheath degeneration and regeneration coexisted at the same time. 8 weeks after operation , nerve fibers regenerated and restored to normal structure. Conclusion The length time curve and density index-time curve of nerve traction injury are consistent with the changes of pathology , which can be used as a supplementary method to evaluate the degeneration and regeneration in nerve injury.

Objective To investigate the correlation between eigenvalues(λ∥ andλ⊥)of sciatic nerve and limb function in a rabbit model of acute nerve traction inj ury for finding the role ofλ∥ andλ⊥ on diagnosis of nerve inj uries.Methods The right sciatic nerves of 32 Newland rabbits were selected to be performed as traction injury,and then left sciatic nerves were treated as control for the sham operation side.MRI DTI scan was performed before and after the operation on 1 day ,3 day,and 1 week,2,3,4,6 and 8 weeks respectively.Theλ∥ andλ⊥ of inj ured sciatic nerves and sham operated nerves were measured,meanwhile functional exami-nations were evaluated,and then analyzing the correlation betweenλ⊥ of inj ured sciatic nerves and the score of inj ured limb function in the periods of 3 days to 8 weeks;finally different portions of sciatic nerve were removed for histological examinations.Results Theλ⊥ of inj ured sciatic nerves in the proximal portion was slightly increased at 3 days and recovered to the normal at 2 weeks.Theλ⊥ of inj ured sciatic nerves in the traction portion and distal portion were slightly raised at 1 day,reached to its maximum value at 3 days,and then decreased gradually after 1 week and dropped to the pre-operation level after 4 weeks.Theλ⊥ of inj ured sciatic nerves in the proximal portions was significantly higher than that of the sham-operated nerves from 1 day to 1 week(F=7.275,P=0.000). Theλ⊥ of inj ured sciatic nerves in the traction portion and distal portion were significantly higher than that of the sham-operated nerves from 1 day to 3 weeks(F=5.851,F=3.794,P=0.001,P=0.000).However,there was no significantly difference between theλ∥ of inj ured nerves in each portion and sham-operated nerves .The negative correlation between theλ⊥ of inj ured sciatic nerves in the distal portion and the score of the nerve function in the injured limb was found (r=-0.938,r=-0.897,P<0.01).Conclu-sion Theλ⊥ of inj ured nerves in the traction portion and distal portion could monitor the process of degeneration and regeneration of sciatic nerve in traction inj ury,while theλ∥ plays no obvious role in diagnosis of nerve inj uries.

BACKGROUND:Magnetic resonance diffusion tensor imaging can display the dispersion changes of peripheral nerve injury and be used to conduct quantitative research, so it has good application prospects in displaying the nerve injury and regeneration. OBJECTIVE:To investigate the possibility of magnetic resonance diffusion tensor imaging of rabbit acute sciatic nerve traction injury, and to figure out the value of diffusion tensor parameters in the diagnosis of peripheral nerve injuries and to reveal the pathologic basis. METHODS:The right hind limb sciatic nerves of 32 New Zealand white rabbits were selected to make the regeneration and repair models, the left hind limb nerves as the sham-operation side. Diffusion tensor imaging examination of sciatic nerves were performed at 1 and 3 days, 1, 2, 3, 4, 6 and 8 weeks after operation with 1.5 T MRI. Fractional anisotropy and apparent diffusion coefficient were measured through diffusion tensor tracing
reconstruction, and then the pathological examination was performed. RESULTS AND CONCLUSION:Diffusion tensor imaging revealed only the proximal nerve, injured nerve as wel as the middle of the distal nerve at 1 day after traction injury. At 1 week, the nerve of distal portion appeared thinner and shorter fiber bundle. At 2-6 weeks after operation, the fiber bundle was increased and thickened. At 8 weeks after operation, the distal nerve fibers had nearly restored to the level before injury. There was significant difference in the fractional anisotropy value of traction portion and distal portions between traction injury and sham-operation group at 1 day-8 weeks after operation (P<0.05). While there was significant difference in the fractional anisotropy value of proximal traction portion between traction injury and sham-operation group 1 day-1 week after operation (P<0.05). There were no significant differences in the apparent diffusion coefficient values between traction injury and sham-operation group at 1 day-8 weeks after operation. Fal of fractional anisotropy value in the early stage of nerve traction injury was the result of myelin sheath broke down and axonal disintegrated;recovery of fractional anisotropy value resulted from myelin sheath proliferated and myelin sheath grew slowly to mature. Diffusion tensor tracing can show the abnormal change of the sciatic nerve with traction injury in rabbit clearly and early, and the measurement of fractional anisotropy value can be used as the sensitive method to monitor the degeneration and regeneration after nerve traction injury.

This paper is aimed to investigate the feasibility of applying the small intestine submucosa (SIS) as the scaffold in constructing tissue engineering cartilage in vitro. We obtained SIS from the small intestine of specific pathogen-free pigs. Then we isolated tunica submucosa layer from the mucosal, muscular, and serosal layers by gentle mechanic abrasion. The SIS was made acellular by combination of detergent and enzyme digestion. The chondrocytes were seeded onto the SIS and were cultured for 3 weeks. The cell growth, attachment and distribution were detected by histochemical stain, immunohistochemical stain and scan electron microscope. The chondrocytes could adhere and grow well on the matrix surface, and synthesize a large of the GAG and type U collagen. However, the chondrocytes grew only on the surface andsuperficial layer of the scaffold, they did not move into the inner part of the scaffold. It could be concluded that SIS has good cellular compatibility without cytotoxicity and provides temporary substrate to which these anchorage-dependent cells can adhere, and stimulate the chondrocytes anchored on the scaffold to proliferate and keep differentiated phenotype. Further study will be needed to promote the ability of chondrocyte chemotaxis in order to distribute the chondrocytes into the whole scaffold uniformly.
Animals ; Cell Adhesion ; Cell Culture Techniques ; Cell Proliferation ; Chondrocytes ; cytology ; Chondrogenesis ; physiology ; Intestinal Mucosa ; cytology ; Intestine, Small ; cytology ; Swine ; Tissue Engineering ; methods ; Tissue Scaffolds

This study was aimed to evaluate the cellular compatibility of the small intestinal submucosal(e) (SIS). Prepared by use of pig jejunum. SIS were cocultured with human embryonic periosteal osteoblasts (HEPOB), human embryonic skin fibroblasts (HESFB) and rabbit renal vascular endothelial cells (RRVEC) respectively. The cell growth, attachment, cell cycle, cell apoptosis rate were detected to evaluate the cellular compatibility of SIS. The three kinds of cells attached onto SIS and grew well. SIS accelerated the growth of RRVEC. No effects of SIS were detected on cell cycle and cell apoptosis rate in the three kinds of cells. SIS has good cellular compatibility without cytotoxicity. The porous structure of SIS is suited for the growth of HEPOB, HESFB and RRVEC in three dimensions in the scaffold. SIS is a good bio-derived material of tissue engineering.
Animals ; Cell Differentiation ; physiology ; Cell Division ; physiology ; Cells, Cultured ; Coculture Techniques ; Extracellular Matrix ; physiology ; Histocompatibility ; Intestinal Mucosa ; cytology ; Jejunum ; cytology ; Osteoblasts ; cytology ; physiology ; Swine ; Tissue Engineering

Titanium alloy material (TC4) samples were treated with nitriding technique. The dynamic friction and wear behavior of the modified layer were examined on a reciprocating sliding rig in artificial saliva. Microhardness, depth profile and wear mechanisms were investigated by means of MVK-H12, TALYSURF6, XPS and microscopy. The results demonstrate that after being treated with nitriding technique the titanium alloy material (TC4) has better tribological behavior and up-graded wear resistance. The wear mechanism involves adhesion.
Adsorption ; Biocompatible Materials ; Dental Alloys ; chemistry ; Dental Materials ; Dental Prosthesis ; Electricity ; Friction ; Humans ; Materials Testing ; Surface Properties ; Titanium ; chemistry