BACKGROUND:In 2019,the modified cortical bone trajectory technique was proposed by our team,significantly improving traditional methods.Previous studies have highlighted its superior biomechanical properties for segment fixation.However,a comprehensive systematic analysis of its specific biomechanical effects on adjacent segment degeneration is lacking,particularly regarding its influence on range of motion and intervertebral disc stress in posterior lumbar interbody fusion and transforaminal lumbar interbody fusion techniques.OBJECTIVE:To investigate the biomechanical effects of modified cortical bone trajectory screw techniques on adjacent segment degeneration in posterior lumbar interbody fusion and transforaminal lumbar interbody fusion.METHODS:CT scans were performed on three human cadaver specimens to establish and validate three-dimensional intact finite element models of the L1-S1 segment.For each of these,the posterior lumbar interbody fusion or transforaminal lumbar interbody fusion with three different fixation techniques was reconstructed at the L4-L5 segment.The L4-L5 segment was fixed using three different internal fixation techniques(modified cortical bone trajectory,cortical bone trajectory,and traditional pedicle screws).The range of motion and von Mises stress of the intervertebral disc of the L3-L4 and L5-S1 segments were recorded with a 400 N compressive load and 7.5 N moments in flexion,extension,left-right bending,and left-right rotation.The impacts of the three internal fixation techniques on adjacent segment degeneration in the two kinds of fusion were compared and analyzed.RESULTS AND CONCLUSION:(1)In the posterior lumbar interbody fusion model,the modified cortical bone trajectory screw group showed a reduced range of motion on adjacent segments(L3-L4,L5-S1)under six loading conditions compared to both the cortical bone trajectory screw group and traditional bone trajectory screw group.Specifically,the modified cortical bone trajectory screw group significantly reduced the maximum stress on the intervertebral disc in the superior adjacent segment(L3-L4)during extension compared to the traditional bone trajectory screw group(P=0.005),while the stress on the intervertebral disc in the inferior adjacent segment(L5-S1)exhibited greater dispersion.Similarly,the cortical bone trajectory screw group also significantly reduced the maximum stress on the intervertebral disc in the superior adjacent segment(L3-L4)during extension compared with the traditional bone trajectory screw group(P=0.03).(2)Compared with transforaminal lumbar interbody fusion,the three internal fixation techniques(modified cortical bone trajectory,cortical bone trajectory,and traditional pedicle screws)showed a trend of reduced range of motion in the inferior adjacent segment(L5-S1)under six loading conditions.In contrast,the maximum stress on the intervertebral discs in both the superior and inferior adjacent segments(L3-L4,L5-S1)exhibited an increasing trend in the posterior lumbar interbody fusion model.(3)It is concluded that in the posterior lumbar interbody fusion model,the modified cortical bone trajectory screw exhibited superior biomechanical properties in reducing the range of motion at adjacent segments,which may have a beneficial effect on reducing the risk of adjacent segment degeneration.

BACKGROUND:In 2019,the modified cortical bone trajectory technique was proposed by our team,significantly improving traditional methods.Previous studies have highlighted its superior biomechanical properties for segment fixation.However,a comprehensive systematic analysis of its specific biomechanical effects on adjacent segment degeneration is lacking,particularly regarding its influence on range of motion and intervertebral disc stress in posterior lumbar interbody fusion and transforaminal lumbar interbody fusion techniques.OBJECTIVE:To investigate the biomechanical effects of modified cortical bone trajectory screw techniques on adjacent segment degeneration in posterior lumbar interbody fusion and transforaminal lumbar interbody fusion.METHODS:CT scans were performed on three human cadaver specimens to establish and validate three-dimensional intact finite element models of the L1-S1 segment.For each of these,the posterior lumbar interbody fusion or transforaminal lumbar interbody fusion with three different fixation techniques was reconstructed at the L4-L5 segment.The L4-L5 segment was fixed using three different internal fixation techniques(modified cortical bone trajectory,cortical bone trajectory,and traditional pedicle screws).The range of motion and von Mises stress of the intervertebral disc of the L3-L4 and L5-S1 segments were recorded with a 400 N compressive load and 7.5 N moments in flexion,extension,left-right bending,and left-right rotation.The impacts of the three internal fixation techniques on adjacent segment degeneration in the two kinds of fusion were compared and analyzed.RESULTS AND CONCLUSION:(1)In the posterior lumbar interbody fusion model,the modified cortical bone trajectory screw group showed a reduced range of motion on adjacent segments(L3-L4,L5-S1)under six loading conditions compared to both the cortical bone trajectory screw group and traditional bone trajectory screw group.Specifically,the modified cortical bone trajectory screw group significantly reduced the maximum stress on the intervertebral disc in the superior adjacent segment(L3-L4)during extension compared to the traditional bone trajectory screw group(P=0.005),while the stress on the intervertebral disc in the inferior adjacent segment(L5-S1)exhibited greater dispersion.Similarly,the cortical bone trajectory screw group also significantly reduced the maximum stress on the intervertebral disc in the superior adjacent segment(L3-L4)during extension compared with the traditional bone trajectory screw group(P=0.03).(2)Compared with transforaminal lumbar interbody fusion,the three internal fixation techniques(modified cortical bone trajectory,cortical bone trajectory,and traditional pedicle screws)showed a trend of reduced range of motion in the inferior adjacent segment(L5-S1)under six loading conditions.In contrast,the maximum stress on the intervertebral discs in both the superior and inferior adjacent segments(L3-L4,L5-S1)exhibited an increasing trend in the posterior lumbar interbody fusion model.(3)It is concluded that in the posterior lumbar interbody fusion model,the modified cortical bone trajectory screw exhibited superior biomechanical properties in reducing the range of motion at adjacent segments,which may have a beneficial effect on reducing the risk of adjacent segment degeneration.

Objective To make a comparative analysis on mechancial properties of the modified cortical bone trajectory(MCBT)nailing technique using a novel variable-diameter screw and the traditional pedicle nailing technique using the cement-augmented pedicle screw(CAPS)in the L4 vertebral body.Merthods CAPS and MCBT instrumentation in the L4 vertebral body model were established by obtaining CT scan data from osteoporotic patients.The finite element method was used to compare the stability,screw axial pull-out force and lumbar spine motion under four working conditions(upper,lower,left and right loads)by using different nailing techniques.Results The axial pull-out force of the screws in MCBT group was 25.3％higher than that of the CAPS group(P＜0.05);the load-displacement ratios of the screws in MCBT group were 14.9％(P＞0.05),23.2％(P＞0.05),and 19.1％(P＜0.05)higher than those of CAPS group under the lower,left,and right working conditions,respectively;the load-displacement ratios of the screws in MCBT group were slightly lower than those of CAPS group under the upper working condition,but the differences were not statistically significant(P＞0.05);under the anterior and posterior flexion conditions,the lumbar spine motion of MCBT group was reduced by 13.3％and 2.5％,respectively,compared with CAPS group;under the left lateral bending,right lateral bending,and axial rotational conditions,the lumbar spine motion of MCBT group was improved by 69.1％,74.6％,and 118.1％,respectively,compared with CAPS group,but these differences were not statistically significant(P＞0.05).Conclusions MCBT screw was slightly better than CAPS in axial resistance to extraction force,and stability of vertebral anterior flexion under lower,left and right working conditions,and slightly weaker than CAPS in stability under upper,left lateral bending,right lateral bending,and axial rotational conditions.This study demonstrates that MCBT screw has certain advantages over CAPS,providing a pre-basic foundation for the clinical application of MCBT nailing technique for treating osteoporosis.

Stem cells play a crucial role in maintaining tissue regenerative capacity and homeostasis. However, mechanisms associated with stem cell senescence require further investigation. In this study, we conducted a proteomic analysis of human dental pulp stem cells (HDPSCs) obtained from individuals of various ages. Our findings showed that the expression of NUP62 was decreased in aged HDPSCs. We discovered that NUP62 alleviated senescence-associated phenotypes and enhanced differentiation potential both in vitro and in vivo. Conversely, the knocking down of NUP62 expression aggravated the senescence-associated phenotypes and impaired the proliferation and migration capacity of HDPSCs. Through RNA-sequence and decoding the epigenomic landscapes remodeled induced by NUP62 overexpression, we found that NUP62 helps alleviate senescence in HDPSCs by enhancing the nuclear transport of the transcription factor E2F1. This, in turn, stimulates the transcription of the epigenetic enzyme NSD2. Finally, the overexpression of NUP62 influences the H3K36me2 and H3K36me3 modifications of anti-aging genes (HMGA1, HMGA2, and SIRT6). Our results demonstrated that NUP62 regulates the fate of HDPSCs via NSD2-dependent epigenetic reprogramming.
Humans ; Dental Pulp/cytology* ; Nuclear Pore Complex Proteins/genetics* ; Cellular Senescence/genetics* ; Stem Cells/metabolism* ; Epigenesis, Genetic ; Cell Proliferation ; Cell Differentiation ; Histone-Lysine N-Methyltransferase/metabolism* ; Cells, Cultured ; Cellular Reprogramming ; Cell Movement ; Proteomics

Background:Acute pancreatitis(AP)is a common clinical gastrointestinal emergency with a high mortality rate.Intestinal dysfunction is one of the common complications of AP and can aggravate the disease condition.Therefore,early and accurate assessment of the disease severity and intestinal dysfunction of AP is of great significance for improving the prognosis of patients.Aims:To investigate the correlation of early serum levels of interleukin-1β(IL-1β),C-reactive protein(CRP),endotoxin(ET),D-lactic acid(D-LA),and diamine oxidase(DAO)with disease severity and intestinal dysfunction in AP patients.Methods:A total of 52 AP patients admitted to the Second Affiliated Hospital of Baotou Medical College from September 2023 to September 2024 were enrolled,and 10 healthy individuals recruited during the same period were served as the control group.AP patients were classified into mild acute pancreatitis(MAP),moderately severe acute pancreatitis(MSAP)and severe acute pancreatitis(SAP)groups according to the severity of the disease.Intestinal function was evaluated using the acute gastrointestinal injury(AGI)grading system.ELISA was used to detect the early serum levels of IL-1β,CRP,ET,D-LA,and DAO,and the correlation of these indicators with the severity of AP and AGI grade were analyzed by Spearman correlation coefficient.Results:Serum levels of IL-1β,CRP,ET,D-LA,and DAO in the MAP,MSAP,and SAP groups were significantly higher than those in the control group(all P<0.05);serum levels of IL-1β,CRP,ET,D-LA,and DAO in the MSAP group were significantly higher than those in the MAP group(all P<0.05);serum levels of IL-1β,CRP,ET,D-LA,and DAO in the SAP group were significantly higher than those in the MAP and MSAP groups(all P<0.05).Compared with AGI grade 0-Ⅰ subjects,serum levels of IL-1β,CRP,ET,D-LA,and DAO in patients with AGI grade Ⅱ,Ⅲ and Ⅳ were significantly increased(all P<0.05).Compared with AGI grade Ⅱ patients,serum D-LA level in patients with AGI grade Ⅲ was significantly increased(P<0.05).Compared with AGI grade Ⅲ patients,serum D-LA level in patients with AGI grade Ⅳ was significantly increased(P<0.05).Serum levels of IL-1β,CRP,ET,D-LA,and DAO were positively correlated with the severity of AP and AGI grade(all P<0.05).Conclusions:Early serum levels of IL-1β,CRP,ET,D-LA,and DAO in AP patients are significantly increased and closely related to the disease severity and intestinal dysfunction.

AIM:To investigate the protective effect and mechanism of zinc ions on lung ischemia/reperfusion injury(LIRI)in rats.METHODS:SPF SD rats aged 6～8 weeks were divided randomly into 4 groups:control(control)group,ischemia/reperfusion(I/R)group,zinc chloride(ZnCl2)+I/R group,and PI3K inhibitor(LY294002)+ZnCl2+I/R group.Inductively coupled plasma mass spectrometry(ICP-MS)was used to measure the concentration of zinc ions in lung tissues,while the degree of lung tissue injury was assessed by HE staining,the alveolar damage index,and the lung wet/dry weight ratio.qPCR was used to detect the mRNA expression of solute carrier family 39 member 8(SLC39A8/ZIP8),with the TUNEL assay used to determine the level of apoptosis in lung tissue.The phosphorylation levels of caspase3,PI3K,AKT,GSK-3β,ZIP8,and solute carrier family 30 member 9(SLC30A9/ZNT9)were detected by Western blot,while the mitochondrial membrane potential was measured by the mitochondrial extraction kit and JC-1 mitochondrial mem-brane potential detection kit.RESULTS:Compared with the I/R group,the zinc ion level in the ZnCl2+I/R group in-creased(P<0.01),with the qPCR results showing that the expression level of ZIP8 also increased(P<0.01).The West-ern blot results demonstrated that the phosphorylation levels of PI3K/AKT/GSK-3β and cleaved caspase-3/pro were both in-creased(P<0.01 or P<0.05).In addition,the level of caspase-3 was decreased(P<0.01),the ZIP8 level was increased(P<0.05),whereas the level of ZNT9 was not significantly different(P>0.05).The mitochondrial membrane potential was increased(P<0.01)and the level of apoptosis was decreased(P<0.01).The results of HE staining,total lung water(TLW),lung index of quantitative assessment of histology(IQA),and lung tissue wet/dry weight ratio showed that the de-gree of injury was reduced significantly(P<0.05 or P<0.01).Compared with the ZnCl2+I/R group,the LY294002+Zn-Cl2+I/R group had a significant reduction in zinc ion levels(P<0.05),while qPCR showed a significant reduction in ZIP8 expression(P<0.01).Western blot showed that the phosphorylation level of PI3K/AKT/GSK-3β was decreased(P<0.01),the level of caspase-3/pro-caspase-3 was increased(P<0.01)the level of ZIP8 was decreased(P<0.05),al-though there was no significant difference in ZNT9(P>0.05).Measurements of the mitochondrial membrane potential demonstrated a significant decrease(P<0.01),while the TUNEL results showed that the level of apoptosis had increased(P<0.05).HE staining,TLW,IQA and lung tissue wet/dry weight ratio indicated that the degree of injury was aggravated significantly(P<0.05 or P<0.01).CONCLUSION:Administration of zinc chloride in rats has a protective role in lung ischemia/reperfusion injury by activating the PI3K/AKT pathway,leading to inactivation of GSK-3β,stabilization of the mitochondrial membrane potential level,and inhibition of cell apoptosis.

Background:Acute pancreatitis(AP)is a common clinical gastrointestinal emergency with a high mortality rate.Intestinal dysfunction is one of the common complications of AP and can aggravate the disease condition.Therefore,early and accurate assessment of the disease severity and intestinal dysfunction of AP is of great significance for improving the prognosis of patients.Aims:To investigate the correlation of early serum levels of interleukin-1β(IL-1β),C-reactive protein(CRP),endotoxin(ET),D-lactic acid(D-LA),and diamine oxidase(DAO)with disease severity and intestinal dysfunction in AP patients.Methods:A total of 52 AP patients admitted to the Second Affiliated Hospital of Baotou Medical College from September 2023 to September 2024 were enrolled,and 10 healthy individuals recruited during the same period were served as the control group.AP patients were classified into mild acute pancreatitis(MAP),moderately severe acute pancreatitis(MSAP)and severe acute pancreatitis(SAP)groups according to the severity of the disease.Intestinal function was evaluated using the acute gastrointestinal injury(AGI)grading system.ELISA was used to detect the early serum levels of IL-1β,CRP,ET,D-LA,and DAO,and the correlation of these indicators with the severity of AP and AGI grade were analyzed by Spearman correlation coefficient.Results:Serum levels of IL-1β,CRP,ET,D-LA,and DAO in the MAP,MSAP,and SAP groups were significantly higher than those in the control group(all P<0.05);serum levels of IL-1β,CRP,ET,D-LA,and DAO in the MSAP group were significantly higher than those in the MAP group(all P<0.05);serum levels of IL-1β,CRP,ET,D-LA,and DAO in the SAP group were significantly higher than those in the MAP and MSAP groups(all P<0.05).Compared with AGI grade 0-Ⅰ subjects,serum levels of IL-1β,CRP,ET,D-LA,and DAO in patients with AGI grade Ⅱ,Ⅲ and Ⅳ were significantly increased(all P<0.05).Compared with AGI grade Ⅱ patients,serum D-LA level in patients with AGI grade Ⅲ was significantly increased(P<0.05).Compared with AGI grade Ⅲ patients,serum D-LA level in patients with AGI grade Ⅳ was significantly increased(P<0.05).Serum levels of IL-1β,CRP,ET,D-LA,and DAO were positively correlated with the severity of AP and AGI grade(all P<0.05).Conclusions:Early serum levels of IL-1β,CRP,ET,D-LA,and DAO in AP patients are significantly increased and closely related to the disease severity and intestinal dysfunction.

Objective To make a comparative analysis on mechancial properties of the modified cortical bone trajectory(MCBT)nailing technique using a novel variable-diameter screw and the traditional pedicle nailing technique using the cement-augmented pedicle screw(CAPS)in the L4 vertebral body.Merthods CAPS and MCBT instrumentation in the L4 vertebral body model were established by obtaining CT scan data from osteoporotic patients.The finite element method was used to compare the stability,screw axial pull-out force and lumbar spine motion under four working conditions(upper,lower,left and right loads)by using different nailing techniques.Results The axial pull-out force of the screws in MCBT group was 25.3％higher than that of the CAPS group(P＜0.05);the load-displacement ratios of the screws in MCBT group were 14.9％(P＞0.05),23.2％(P＞0.05),and 19.1％(P＜0.05)higher than those of CAPS group under the lower,left,and right working conditions,respectively;the load-displacement ratios of the screws in MCBT group were slightly lower than those of CAPS group under the upper working condition,but the differences were not statistically significant(P＞0.05);under the anterior and posterior flexion conditions,the lumbar spine motion of MCBT group was reduced by 13.3％and 2.5％,respectively,compared with CAPS group;under the left lateral bending,right lateral bending,and axial rotational conditions,the lumbar spine motion of MCBT group was improved by 69.1％,74.6％,and 118.1％,respectively,compared with CAPS group,but these differences were not statistically significant(P＞0.05).Conclusions MCBT screw was slightly better than CAPS in axial resistance to extraction force,and stability of vertebral anterior flexion under lower,left and right working conditions,and slightly weaker than CAPS in stability under upper,left lateral bending,right lateral bending,and axial rotational conditions.This study demonstrates that MCBT screw has certain advantages over CAPS,providing a pre-basic foundation for the clinical application of MCBT nailing technique for treating osteoporosis.

AIM:To investigate the protective effect and mechanism of zinc ions on lung ischemia/reperfusion injury(LIRI)in rats.METHODS:SPF SD rats aged 6～8 weeks were divided randomly into 4 groups:control(control)group,ischemia/reperfusion(I/R)group,zinc chloride(ZnCl2)+I/R group,and PI3K inhibitor(LY294002)+ZnCl2+I/R group.Inductively coupled plasma mass spectrometry(ICP-MS)was used to measure the concentration of zinc ions in lung tissues,while the degree of lung tissue injury was assessed by HE staining,the alveolar damage index,and the lung wet/dry weight ratio.qPCR was used to detect the mRNA expression of solute carrier family 39 member 8(SLC39A8/ZIP8),with the TUNEL assay used to determine the level of apoptosis in lung tissue.The phosphorylation levels of caspase3,PI3K,AKT,GSK-3β,ZIP8,and solute carrier family 30 member 9(SLC30A9/ZNT9)were detected by Western blot,while the mitochondrial membrane potential was measured by the mitochondrial extraction kit and JC-1 mitochondrial mem-brane potential detection kit.RESULTS:Compared with the I/R group,the zinc ion level in the ZnCl2+I/R group in-creased(P<0.01),with the qPCR results showing that the expression level of ZIP8 also increased(P<0.01).The West-ern blot results demonstrated that the phosphorylation levels of PI3K/AKT/GSK-3β and cleaved caspase-3/pro were both in-creased(P<0.01 or P<0.05).In addition,the level of caspase-3 was decreased(P<0.01),the ZIP8 level was increased(P<0.05),whereas the level of ZNT9 was not significantly different(P>0.05).The mitochondrial membrane potential was increased(P<0.01)and the level of apoptosis was decreased(P<0.01).The results of HE staining,total lung water(TLW),lung index of quantitative assessment of histology(IQA),and lung tissue wet/dry weight ratio showed that the de-gree of injury was reduced significantly(P<0.05 or P<0.01).Compared with the ZnCl2+I/R group,the LY294002+Zn-Cl2+I/R group had a significant reduction in zinc ion levels(P<0.05),while qPCR showed a significant reduction in ZIP8 expression(P<0.01).Western blot showed that the phosphorylation level of PI3K/AKT/GSK-3β was decreased(P<0.01),the level of caspase-3/pro-caspase-3 was increased(P<0.01)the level of ZIP8 was decreased(P<0.05),al-though there was no significant difference in ZNT9(P>0.05).Measurements of the mitochondrial membrane potential demonstrated a significant decrease(P<0.01),while the TUNEL results showed that the level of apoptosis had increased(P<0.05).HE staining,TLW,IQA and lung tissue wet/dry weight ratio indicated that the degree of injury was aggravated significantly(P<0.05 or P<0.01).CONCLUSION:Administration of zinc chloride in rats has a protective role in lung ischemia/reperfusion injury by activating the PI3K/AKT pathway,leading to inactivation of GSK-3β,stabilization of the mitochondrial membrane potential level,and inhibition of cell apoptosis.

AIM:To investigate the regulatory role of retinoid X receptor(RXR)in oxidative stress response of rat type Ⅱ alveolar epithelial cells(AECII)induced by hypoxia/reoxygenation(HR).METHODS:The AECII were di-vided into control(C)group,HR group,HR+solvent dimethyl sulfoxide(DMSO)group(HD group),HR+RXR agonist 9-cis-retinoic acid(9-RA)group(RA group),and HR+RXR antagonist HX531 group(HX group).Cell Counting Kit-8(CCK-8)method was used to measure the cell viability.Immunofluorescence staining was used to detect the expression of surfactant protein A(SP-A)and RXRα in AECII.Kits were detected to the levels of superoxide dismutase(SOD)and malondialdehyde(MDA)in cells.Transmission electron microscopy was used to observe the ultrastructural changes of the cells.Western blot was used to detect the protein level of nuclear factor E2-related factor 2(Nrf2).RT-PCR was used to detect the expression level of Nrf2 mRNA.RESULTS:Compared with C group,the cell viability and SOD activity in HR,HD,RA and HX groups were decreased significantly(P<0.05),the MDA content were increased significantly(P<0.05),the Nrf2 mRNA and protein expression levels were decreased significantly(P<0.05 or P<0.01),and the immuno-fluorescence expression of RXRα was significantly increased(P<0.01).Compared with HR and HX groups,the cells in RA group showed significantly increased cell viability(P<0.05),increased SOD activity(P<0.05),decreased MDA con-tent(P<0.05),increased Nrf2 mRNA and protein expression levels(P<0.01),and significantly increased immunofluo-rescence expression of RXRα(P<0.01).CONCLUSION:Hypoxia/reoxygenation can aggravate the oxidative stress re-sponse of rat AECII,and RXR agonist intervention can alleviate HR-induced rat AECII injury by inhibiting oxidative stress.