OBJECTIVES: This study explores the differences in fluid flow within alveolar cancellous bone at various sites under orthodontic forces and elucidates the relationship between fluid shear stress and bone remodeling. These fin-dings lay the groundwork for understanding the biomechanical mechanisms of orthodontic tooth movement. METHODS: Stress relaxation tests were performed on human alveolar bone samples to determine material parameters by using the Prony series. An inverse model of alveolar bone was then developed for numerical simulations of fluid-structure interactions to calculate fluid flow within cancellous bone. Meanwhile, a rat model of tooth movement was established to investigate variations in bone remodeling speeds across different regions. RESULTS: The microstructural distribution of cancellous alveolar bone was similar in humans and rats. The bone volume fraction and trabecular thickness gradually decreased from root cervical region to root apical region, while the trabecular space gradually increased. Under the influence of orthodontic forces, fluid shear stress within cancellous bone showed spatial variability across different levels, with the highest shear stress occurring at the root apical region, ranging from 0 to 0.936 6 Pa. Additionally, the rat model of tooth movement indicated that bone remodeling occurred more rapidly at the root apical region. CONCLUSIONS Fluid stimulation has a remarkable effect on al-veolar bone remodeling, causing changes in the structure of alveolar bone and ultimately regulating the speed of structu-ral remodeling.
Bone Remodeling ; Animals ; Tooth Movement Techniques ; Rats ; Alveolar Process/physiology* ; Stress, Mechanical ; Humans ; Biomechanical Phenomena ; Cancellous Bone/physiology* ; Shear Strength

BACKGROUND:Tendinopathy is a musculoskeletal disorder characterized by pain and decreased mobility,with pathological changes of disturbed collagen and hyperplasia of the vasculature.Tendinopathy tends to occur in athletes,physical workers,and the elderly.One of the mechanisms of tendinopathy is the"failed healing response",and part of what causes the failed healing response is the erroneous differentiation of tendon stem/progenitor cells. OBJECTIVE:By reviewing the relevant literature,we introduce the characteristics of tendon stem/progenitor cells,summarize the factors that affect the differentiation of tendon stem/progenitor cells to tendon cells and those that lead to mis-differentiation of tendon stem/progenitor cells(differentiation to adipocytes,osteocytes and chondrocytes),and also describe the limitations of tendon stem/progenitor cells in clinical applications. METHODS:PubMed and Web of Science databases were searched for the terms"tendon stem/progenitor cells,tendinopathy,tendon injury,differentiation".The relevant literature was screened by reading and 109 articles were included for the analysis of the results. RESULTS AND CONCLUSION:(1)Tendon stem/progenitor cells are a type of stem cells that can spontaneously differentiate into tendons and have the ability to self-renew,clone,and multi-differentiate.Various external conditions acting on tendon stem/progenitor cells can lead them to differentiate in diverse directions.The specific factors that regulate the fate of tendon stem/progenitor cells are not known with certainty.When stem cell renewal and differentiation in tendons becomes abnormal,it can lead to failure of tendon healing and consequently to tendinopathy.(2)Aging,changes in extracellular matrix composition,excessive mechanical stimulation,prostaglandin E2 and interleukin-6 as well as interleukin-10 and some systemic diseases may be important in regulating the mis-differentiation of tendon stem/progenitor cells.(3)Possible favorable factors that promote the differentiation of tendon stem/progenitor cells to tenocytes are:some growth factors and cytokines,moderate mechanical stimulation and topography of the extracellular matrix,low oxygen tension,drugs,and several transcriptional genes and proteins.(4)The most desirable therapeutic tools are the regulation of endogenous tendon stem/progenitor cells or the stimulation of endogenous tendon stem/progenitor cell proliferation and differentiation by exogenous tendon stem/progenitor cells.(5)Understanding the factors that regulate mis-differentiation of tendon stem/progenitor cells may provide insight into the pathogenesis of tendinopathy and identify therapeutic targets.Elaborating on the induction of tendon stem/progenitor cell differentiation into tendons could facilitate their use in tissue engineering.

Purpose To explore the ability of proton density fat fraction(PDFF)and decay constant T2* values in MRI to reflect skeletal muscle aging.Materials and Methods 3T MRI data of skeletal muscle in the middle thigh of 211 healthy adults from the Third Affiliated Hospital of Southern Medical University from August to December 2023 were prospectively collected.Gender,age,height,weight and body mass index(BMI)were recorded.PDFF value and T2* value of thigh skeletal muscle were measured at post-processing workstation,and statistical differences among different age,gender and BMI groups were analyzed.The correlation between PDFF value and T2* value of thigh skeletal muscle and age and BMI was analyzed.Results There were statistically significant differences in PDFF values of thigh skeletal muscle among different age groups(H=18.476-85.619,all P<0.01).There were significantly differences in T2*values of the left and right quadriceps muscles,hamstrings and adductors among different age groups(H=13.342-47.566,all P<0.05).There were statistically significant differences in the PDFF values of right quadriceps,left and right hamstring,adductor and sartor muscles between male and female groups(Z=-4.929--1.626,all P<0.05),while there were statistically significant differences in T2* values of left sartor muscle(Z=-2.971,P=0.003).There was no statistical significance in PDFF value of skeletal muscle of thigh in different BMI groups(P>0.05),but there were statistically significant differences in T2* value of left and right quadriceps muscle,hamstring muscle and adductor muscle(H=9.542-24.495,all P<0.05).There was a moderate positive correlation between age and PDFF value of thigh skeletal muscle(r=0.635,P<0.01),but a slight negative correlation with T2* value of left and right quadriceps,hamstring and sarcoleus(r=-0.451--0.189,all P<0.01).There was a slight positive correlation between BMI and T2* values of thigh skeletal muscle(r=0.317,P<0.01).There was a moderate negative correlation between the PDFF value and T2* value of all thigh skeletal muscles(r=-0.749--0.624,P<0.01).The PDFF and T2* values of the front and back thigh muscles(quadriceps,hamstring)were most significantly correlated with age and BMI.Conclusion PDFF based on MRI can reflect the age-related changes in the microenvironment of thigh skeletal muscle,and is a potential imaging biological marker for accurate and non-invasive quantitative evaluation of thigh skeletal muscle aging.

Heracleum candicans is extensively utilized for its abundant medicinal components,which are applied in various treatments,including insecticides,hemostatic agents,dispersing wind,relieving cough,and alleviating rheumatic pain.This paper reviewed the various chemical constituents and pharmacological effects of Heracleum candicans.It aims to provide new insights for its promotion and application,as well as to provide a basis for establishing quality standards for Heracleum candicans.

Frailty in elderly patients undergoing arthroplasty increases the risk of postoperative complications, prolongs hospital stays, delays the rehabilitation process, and aggravates the economic burden. Frailty is a dynamic condition, and early detection and effective intervention can delay its progression. Therefore, early assessment of frailty status in patients is necessary. Currently, there are numerous frailty assessment tools, but the selection of these tools lacks a solid basis. This paper reviews the impact of frailty on the physical condition of elderly arthroplasty patients, as well as the content, application, advantages, and limitations of existing frailty assessment tools at home and abroad. Furthermore, it summarizes the problems in the process of frailty assessment and puts forward prospects, aiming to provide reference for the identification and assessment of frailty in elderly arthroplasty patients in the future.

OBJECTIVES: The magnesium depletion score (MDS) is considered more reliable than traditional approaches for predicting magnesium deficiency in humans. We explored the associations of MDS and dietary magnesium intake with diabetes. METHODS: We obtained data from 18,853 participants in the National Health and Nutrition Examination Survey 2011-2018. Using multivariate regression and stratified analysis, we investigated the relationships of both MDS and magnesium intake with diabetes. To compute prevalence ratios (PRs), we employed modified Poisson or log-binomial regression. We characterized the non-linear association between magnesium intake and diabetes using restricted cubic spline analysis. RESULTS: Participants with MDS ≥2 exhibited a PR of 1.26 (95% confidence interval [CI], 1.19 to 1.34) for diabetes. Per-standard deviation (SD) increase in dietary magnesium intake was associated with a lower prevalence of diabetes (PR, 0.91; 95% CI, 0.87 to 0.96). Subgroup analyses revealed a positive association between MDS ≥2 and diabetes across all levels of dietary magnesium intake, including the lowest (PR, 1.35; 95% CI, 1.18 to 1.55), middle (PR, 1.23; 95% CI, 1.12 to 1.35), and highest tertiles (PR, 1.25; 95% CI, 1.13 to 1.37; pinteraction<0.001). Per-SD increase in magnesium intake was associated with lower diabetes prevalence in participants with MDS <2 (PR, 0.92; 95% CI, 0.87 to 0.98) and those with MDS ≥2 (PR, 0.91; 95% CI, 0.84 to 0.98; pinteraction=0.030). CONCLUSIONS MDS is associated with diabetes, particularly among individuals with low magnesium intake. Adequate dietary magnesium intake may reduce diabetes risk, especially in those with high MDS.

OBJECTIVES: To investigate the role of mitochondrial autophagy disorder caused by deletion of E3 ubiquitin ligase Parkin in neuroinflammation in a mouse model of MPTP-induced Parkinson's disease (PD). METHODS: Wild-type (WT) male C57BL/6 mice and Parkin^-/- mice were given intraperitoneal injections with MPTP or PBS for 5 consecutive days, and the changes in motor behaviors of the mice were observed using open field test. The effects of Parkin deletion on PD development and neuroinflammation were evaluated using immunofluorescence and Western blotting. The changes of the PINK 1/Parkin signaling pathway in the midbrain substantia nigra of the mice were examined to explore the molecular mechanism of Parkin-mediated regulation of mitochondrial autophagy and its effect on neuroinflammation in PD mice. RESULTS: Compared with their WT counterparts, the Parkin^-/- mice with MPTP injections exhibited significant impairment of motor function with decreased TH⁺ neurons, increased α-synuclein (α-syn) accumulation, and increased numbers of GFAP⁺ and I-ba1⁺ cells in the midbrain substantia nigra. Parkin deletion obviously affected PINK1/Parkin-mediated mitochondrial autophagy to result in significantly increased mtDNA and upregulated expressions of STING and NLRP3 inflammatosomes in the midbrain substantia nigra of MPTP-treated transgenic mice. CONCLUSIONS Parkin deletion causes mitochondrial autophagy disorder to accelerate PD progression and exacerbates neuroinflammation in mice by affecting the PINK1/Parkin signaling pathway, suggesting the important role of Parkin in early pathogenesis of PD.
Animals ; Ubiquitin-Protein Ligases/genetics* ; Mice ; Mice, Inbred C57BL ; Male ; Parkinson Disease/genetics* ; Protein Kinases/genetics* ; Mitochondria/metabolism* ; Disease Models, Animal ; Autophagy ; Signal Transduction ; Neuroinflammatory Diseases/metabolism* ; Mice, Knockout ; alpha-Synuclein/metabolism* ; Substantia Nigra/metabolism* ; Mitophagy ; Disease Progression

The formation of learning and memory is regulated by synaptic plasticity in hippocampal neurons. Here we explored how gestational exposure to dexamethasone, a synthetic glucocorticoid commonly used in clinical practice, has lasting effects on offspring's learning and memory. Adult offspring rats of prenatal dexamethasone exposure (PDE) displayed significant impairments in novelty recognition and spatial learning memory, with some phenotypes maintained transgenerationally. PDE impaired synaptic transmission of hippocampal excitatory neurons in offspring of F1 to F3 generations, and abnormalities of neurotransmitters and receptors would impair synaptic plasticity and lead to impaired learning and memory, but these changes failed to carry over to offspring of F5 and F7 generations. Mechanistically, altered hippocampal miR-133a-3p-SIRT1-CDK5-NR2B signaling axis in PDE multigeneration caused inhibition of excitatory synaptic transmission, which might be related to oocyte-specific high expression and transmission of miR-133a-3p. Together, PDE affects hippocampal excitatory synaptic transmission, with lasting consequences across generations, and CDK5 in offspring's peripheral blood might be used as an early-warning marker for fetal-originated learning and memory impairment.

AIM:To explore the effect and mechanism of hydrogen sulfide(H2S)on autophagy and angiogene-sis in skin wound of diabetic rats.METHODS:Among 36 healthy 8-week-old male Sprague-Dawley rats,12 rats were se-lected as control group,and the remaining rats were intraperitoneally injected with streptozotocin(STZ)to induce diabetic model and were randomly divided into diabetes mellitus(DM)group and NaHS(H2S donor)intervention(DM+NaHS)group,with 12 rats in each group.A skin trauma model was established by excising the skin of the back of rats in each group.The rats in DM+NaHS group were intraperitoneally injected with NaHS(56 μmol/kg),and the rats in control and DM groups were daily received the same volume of normal saline for 21 consecutive days.The healing of skin wound was measured on days 0,7,14 and 21 after operation.On the 21st day after surgery,the content of H2S in skin tissues was de-tected by C-7Az fluorescent probe,and the morphological changes and angiogenesis of wound tissues were observed by HE staining.The expression of CD31 was detected by immunofluorescence staining,and endothelial autophagy was detected by double staining of CD31 and beclin-1.The protein levels of cystathionine γ-lyase(CSE),CD31,microtubule-associated protein 1 light chain 3(LC3),beclin-1,P62,Bcl-2,Bax,phosphatidylinositol 3-kinase(PI3K),protein kinase B(PKB/Akt)and mammalian target of rapamycin(mTOR)in wound tissues were determined by Western blot.Caspase-3 and propidium iodide(PI)staining was used to detect cell apoptosis,and apoptosis of vascular endothelial cells was deter-mined with CD31 and TUNEL double immunofluorescence staining.RESULTS:Compared with DM group,the wound healing rate,H2S content and CSE protein expression were significantly increased in DM+NaHS group(P＜0.01),but still lower than those in control group(P＜0.01).HE staining showed that the wound surface in DM group was thin and wide,with few capillary,while that in DM+NaHS group was thicker with lots of capillary and wound width was reduced.Com-pared with DM group,CD31 expression was markedly increased(P＜0.01),the fluorescence intensity of caspase-3 and PI was significantly decreased(P＜0.01),and CD31+/beclin-1+ as well as CD31+/TUNEL+ cells were decreased(P＜0.01)in DM+NaHS group.Western blot analysis showed that compared with DM group,the levels of beclin-1,Bax and LC3-Ⅱ/LC3-Ⅰ were significantly decreased(P＜0.01),while the levels of P62 and Bcl-2,as well as ratios of p-PI3K/PI3K,p-Akt/Akt and p-mTOR/mTOR were significantly increased(P＜0.01)in DM+NaHS group.CONCLUSION:H2S can promote skin wound healing,which may be related to activation of PI3K/Akt/mTOR signaling pathway,inhibition of endothelial au-tophagy and apoptosis,and promotion of angiogenesis in diabetic rats.

Objective:To investigate the impact of switching to low iodine drinking water in areas with high water iodine levels on the iodine nutritional status and thyroid function of pregnant women.Methods:A cross-sectional survey was conducted in Gaoqing County, Zibo City, Shandong Province. Pregnant women who underwent prenatal examinations at the Obstetrics Clinic of Gaoqing County People's Hospital from 2019 to 2021 were selected as the survey subjects. With reference to the Criteria for the Classification of Water Source High Iodine Areas and High Iodine Disease Areas (GB/T 19380-2016), pregnant women with drinking water iodine > 100 μg/L were considered as the high water iodine group and ≤100 μg/L was the non-high water iodine group. Basic information, one random urine sample, fasting blood sample, 24-hour urine sample and drinking water sample of pregnant women were collected, and thyroid ultrasound examination was performed on pregnant women. Urinary iodine (UI) concentration (UIC) and drinking water iodine concentration (WIC) were measured by inductively coupled plasma mass spectrometry, and 24-hour urinary iodine excretion (UIE) and daily iodine intake (TII) of pregnant women were calculated. Serum thyroid hormone (TSH), free triiodothyronine (FT 3), free thyroxine (FT 4), thyroid peroxidase antibody (TPOAb) and anti-thyroid autoantibodies (TgAb) were determined by automatic chemiluminescence immunoassay. Creatinine (CR) was determined using deproteinized endpoint microplate method and UI/CR was calculate. Results:A total of 797 pregnant women were included, and the UIC was 150.2 (88.1, 281.3) μg/L, the iodine nutrition was generally at an appropriate level. Among them, 584 pregnant women in the non-high water iodine group had a UIC of 120.9 (74.9, 191.5) μg/L, which was at the iodine deficiency level; 213 pregnant women in the high water iodine group had a UIC of 321.1 (201.9, 569.1) μg/L, which was at the iodine super-appropriate level; the differences in WIC, UIC, UIE, TII, and UI/CR between the two groups were statistically significant ( Z = 21.63, 13.34, 15.14, 15.14, 11.81, P < 0.001). After stratification by different gestational periods, the differences were statistically significant when comparing WIC and TSH in pregnant women in the non-high water iodine group and UI/CR in pregnant women in the high water iodine group by gestational period ( H = 59.13, 7.30, 13.60, P < 0.05). A total of 744 pregnant women were tested for thyroid function, and 128 cases of TSH > 2.5 mU/L, 15 cases of hypothyroxemia, and 19 cases of subclinical hypothyroidism were detected, with detection rates of 17.2%, 2.0%, and 2.6%, respectively. The differences were statistically significant when comparing TSH and TPOAb levels and the proportion of pregnant women with TSH > 2.5 mU/L in the high water iodine and non-high water iodine groups ( Z = 3.04, - 2.17, χ 2 = 6.94, P = 0.002, 0.030, 0.008). The thyroid glands of pregnant women were examined in 720 cases, and 30 cases of goiter and 150 cases of thyroid nodules were detected, with detection rates of 4.2% and 20.8%, respectively. The median thyroid volume was 8.92 ml in the high water iodine group and 8.60 ml in the non-high water iodine group, which were both within the normal range, with no statistically significant difference between the groups ( Z = - 0.75, P = 0.455). Conclusions:After changing to low iodine water, the overall iodine nutrition of pregnant women in Gaoqing County is now at an appropriate level, and the reduction of water iodine effectively reduces the risk of TSH abnormalities in local pregnant women. However, pregnant women in the non-high water iodine group are iodine deficiency, and pregnant women in the high water iodine group are at iodine super-appropriate, and the iodine nutrition level of pregnant women in this area is highly variable, which causes the "illusion" that the overall iodine level of local pregnant women is suitable.