1.One-year clinical observation of epithelial-off accelerated corneal collagen cross-linking on the treatment of progressive keratoconus
Jing LU ; Ping MA ; Changjun LAN
International Eye Science 2025;25(3):451-454
AIM: To assess the clinical efficacy and safety of epithelial-off accelerated corneal collagen cross-linking(CXL)in the management of progressive keratoconus over 1 a period.METHODS:A retrospective pre-post self-controlled study. Data were collected from complete cases of 63 patients(84 eyes)with progressive keratoconus who underwent epithelial-off accelerated CXL between August 2018 and September 2021. Uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), refraction, corneal transparency, maximum keratometry(Kmax)of the anterior corneal surface, minimum corneal thickness, endothelial cell counts, and intraocular pressure(IOP)were analyzed preoperatively and at 1, 3, 6, and 12 mo postoperatively.RESULTS:No significant differences were observed in UCVA and spherical power before and after surgery(all P>0.05). However, there were significant differences in BCVA, cylinder power, Kmax, minimum corneal thickness, and IOP(all P<0.05). At 12 mo postoperatively, there were no significant differences in BCVA, cylinder power, minimum corneal thickness, and IOP compared with preoperative values(all P>0.05), while Kmax was decreased compared with preoperative value(P<0.05). At 1 mo postoperatively, the corneal endothelial cell count(2519.87±345.28 cells/mm2)was decreased compared with preoperative value(2693.63±313.39 cells/mm2; P<0.001). At 1 wk postoperatively, 22 eyes developed corneal haze(grade 0.5 to 1), and 15 eyes presented with linear corneal stromal opacity at 1 mo postoperatively. In 7 eyes, corneal opacity subsided within 3 to 6 mo after the operation, however, 5 eyes still exhibited corneal nebula or macula without affecting visual acuity.CONCLUSION: After epithelial-off accelerated CXL, the UCVA, BCVA and spherical diopter of patients remained stable over time. The astigmatism and corneal curvature temporarily increased and then gradually decreased. The cornea minimum thickness decreased initially but subsequently returned to preoperative levels. The corneal curvature at 6 and 12 mo after surgery was significantly lower than that before surgery, which could effectively prevent the progression of keratoconus. Despite potential localized corneal opacity and macular complications, as well as a possible decrease in corneal endothelial cell count, BCVA remained unaffected, demonstrating favorable safety outcomes.
2.One-year clinical observation of epithelial-off accelerated corneal collagen cross-linking on the treatment of progressive keratoconus
Jing LU ; Ping MA ; Changjun LAN
International Eye Science 2025;25(3):451-454
AIM: To assess the clinical efficacy and safety of epithelial-off accelerated corneal collagen cross-linking(CXL)in the management of progressive keratoconus over 1 a period.METHODS:A retrospective pre-post self-controlled study. Data were collected from complete cases of 63 patients(84 eyes)with progressive keratoconus who underwent epithelial-off accelerated CXL between August 2018 and September 2021. Uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), refraction, corneal transparency, maximum keratometry(Kmax)of the anterior corneal surface, minimum corneal thickness, endothelial cell counts, and intraocular pressure(IOP)were analyzed preoperatively and at 1, 3, 6, and 12 mo postoperatively.RESULTS:No significant differences were observed in UCVA and spherical power before and after surgery(all P>0.05). However, there were significant differences in BCVA, cylinder power, Kmax, minimum corneal thickness, and IOP(all P<0.05). At 12 mo postoperatively, there were no significant differences in BCVA, cylinder power, minimum corneal thickness, and IOP compared with preoperative values(all P>0.05), while Kmax was decreased compared with preoperative value(P<0.05). At 1 mo postoperatively, the corneal endothelial cell count(2519.87±345.28 cells/mm2)was decreased compared with preoperative value(2693.63±313.39 cells/mm2; P<0.001). At 1 wk postoperatively, 22 eyes developed corneal haze(grade 0.5 to 1), and 15 eyes presented with linear corneal stromal opacity at 1 mo postoperatively. In 7 eyes, corneal opacity subsided within 3 to 6 mo after the operation, however, 5 eyes still exhibited corneal nebula or macula without affecting visual acuity.CONCLUSION: After epithelial-off accelerated CXL, the UCVA, BCVA and spherical diopter of patients remained stable over time. The astigmatism and corneal curvature temporarily increased and then gradually decreased. The cornea minimum thickness decreased initially but subsequently returned to preoperative levels. The corneal curvature at 6 and 12 mo after surgery was significantly lower than that before surgery, which could effectively prevent the progression of keratoconus. Despite potential localized corneal opacity and macular complications, as well as a possible decrease in corneal endothelial cell count, BCVA remained unaffected, demonstrating favorable safety outcomes.
3.Advances in the clinical treatment of osteoporotic vertebral compression fractures
Changjun CHEN ; Qingwei MA ; Lei ZHANG ; Qiuru WANG ; Dayong PENG ; Meng CHEN ; Yun YANG ; Kaining ZHANG ; Weinan ZENG ; Tingbin YAN
Journal of Chongqing Medical University 2025;50(4):488-495
Osteoporotic vertebral compression fractures(OVCFs)are common orthopedic conditions that can lead to spinal pain and deformity,which greatly affects the quality of life of patients.Currently,there are various treatment methods for OVCFs,but there is still a lack of standards for optimal treatment modalities.Therefore,this article introduces the current treatment methods and character-istics of epidemiology for OVCFs,in order to improve the awareness of this disease among clinicians and provide a reference for select-ing more appropriate treatment regimens.Conservative treatment measures,such as bracing and analgesia,are the basic treatment mea-sures for OVCFs,and anti-osteoporosis drugs play a crucial role in management.Minimally invasive procedures,including percutane-ous vertebroplasty and percutaneous balloon kyphoplasty,remain the primary surgical interventions,and traditional open surgeries are also an important part of treatment,such as anterior spinal fusion,combined anterior and posterior spinal fusion,posterior spinal fusion with three-column osteotomy,and posterior spinal fusion with vertebroplasty.Furthermore,surgeons should focus on the accumulation of related surgical techniques and skills during surgery to effectively address the challenges and complications associated with surgical interventions.Finally,scientific and appropriate treatment methods should be selected for patients,in order to improve long-term treat-ment outcomes and increase the degree of satisfaction among pa-tients.
4.Mechanism of 4-methylcatechol in inhibiting fibroblast-like synoviocyte migration and suppressing inflammatory responses in treatment of rheumatoid arthritis.
Zhendong YING ; Peng WANG ; Lei ZHANG ; Dailing CHEN ; Qiuru WANG ; Qibin LIU ; Tiantian TANG ; Changjun CHEN ; Qingwei MA
Chinese Journal of Reparative and Reconstructive Surgery 2025;39(8):1051-1060
OBJECTIVE:
To investigate the effects of 4-methylcatechol (4MC) on the migration and inflammatory response in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS), as well as its underlying mechanisms of action.
METHODS:
RA-FLS was isolated from synovial tissue donated by RA patients, and the optimal concentration of 4MC was determined by cell counting kit 8 method for subsequent experiments, and the effect of 4MC on the migratory ability of RA-FLS was evaluated via a cell scratch assay. An inflammation model of RA-FLS was induced by tumor necrosis factor α (TNF-α). Real-time fluorescence quantitative PCR and ELISA were employed to detect the gene and protein expression levels of interleukin-1β (IL-1β) and IL-6 in RA-FLS and their culture supernatants, respectively, thereby investigating the anti-inflammatory effects of 4MC. Western blot was used to examine the expressions of nuclear factor κB (NF-κB) signaling pathway-related proteins, including inhibitor of NF-κB-α (IKBα), phosphorylated (P)-IκBα, NF-κB-inducing kinase α (IKKα), P-IKKαβ, P-p65, and p65. Cellular immunofluorescence was utilized to detect the expression and localization of p65 in RA-FLS, exploring whether 4MC exerts its anti-inflammatory effects by regulating the NF-κB signaling pathway. Finally, a collagen-induced arthritis (CIA) mouse model was established. The anti-RA effect of 4MC in vivo was evaluated by gross observation and histological examination.
RESULTS:
4MC inhibited RA-FLS migration in a concentration-dependent manner. In the TNF-α-induced RA-FLS inflammation model, 4MC significantly decreased the gene and protein expression levels of IL-1β and IL-6. Furthermore, 4MC markedly reduced the ratios of P-IΚBα/IΚBα, P-IKKαβ/IKKα, and P-p65/p65, thereby blocking the transcriptional activity of p65 by inhibiting its nuclear translocation. This mechanism effectively suppressed the activation of the TNF-α-mediated NF-κB signaling pathway. Animal studies demonstrated that 4MC [10 mg/(kg·day)] significantly lowered serum levels of IL-1β, IL-6, and TNF-α, and alleviated arthritis severity and bone destruction in CIA mice.
CONCLUSION
4MC not only inhibits the migration of RA-FLS but also mitigates their inflammatory response by suppressing the NF-κB signaling pathway, thereby effectively exerting its anti-RA effects.
Synoviocytes/metabolism*
;
Arthritis, Rheumatoid/metabolism*
;
Animals
;
Cell Movement/drug effects*
;
Humans
;
Catechols/therapeutic use*
;
Fibroblasts/drug effects*
;
Mice
;
Tumor Necrosis Factor-alpha/pharmacology*
;
Interleukin-1beta/metabolism*
;
Interleukin-6/metabolism*
;
Signal Transduction/drug effects*
;
NF-kappa B/metabolism*
;
Transcription Factor RelA/metabolism*
;
Synovial Membrane/cytology*
;
Cells, Cultured
;
Male
;
Arthritis, Experimental
;
Anti-Inflammatory Agents/pharmacology*
;
NF-KappaB Inhibitor alpha
;
Inflammation
5.In vivo production of anti-CD19 CAR-T cells with T cell-targeted engineered exosomes to evaluate cytotoxicity against lymphoma cells
Dong TING ; Zhou YING ; Yu BOYU ; Xia XUEJIAO ; Ma YIGE ; Ma YAN ; Gao YANG ; Zhou MENGYING ; Wang CHANGJUN ; Li QIUYI ; Gu CHAOJIANG
Chinese Journal of Clinical Oncology 2025;52(6):279-286
Objective:Chimeric antigen receptor T-cell(CAR-T)immunotherapy has made major breakthroughs in the treatment of blood tu-mors.However,current CAR-T therapies face several limitations:they require autologous cells,involve a lengthy and costly production pro-cess,and use lentiviral transduction that carry risk of insertional carcinogenesis due to random integration.Therefore,there is an urgent need to develop a universal cost-effective cancer immunotherapy method generating CAR-T cells for in vivo cancer immunotherapy.Meth-ods:This study successfully established an exosome-mediated,T-cell targeted delivery system,demonstrating both precise design and func-tional efficacy for biomedical applications.To optimize CAR-T cell generation the transfection dose was adjusted,and the kinetics of CAR-T cell percentage were recorded.The cytotoxicity of the resulting CAR-T cells was evaluated in vitro by calcein-AM release.To test the tumor-killing in vivo of engineered exosomes,human PBMCs were injected into NPG mice via the tail vein to establish humanized mice,followed by intravenous injection of tumor cells to induce cancer.Results:To overcome the limitations of conditional autologous CAR-T cells,we de-veloped a T cell-targeted exosome system capable of specifically targeting human CD3+,CD4+,and CD8+T cells.CAR-T production was dose-dependent,with transfection efficiency reaching upto 97.8%at 106 particles/cell.Both in vitro cytotoxicity assays and in vivo animal experi-ments demonstrated that exosome-incubated CAR-T cells effectively eliminated CD19-positive Raji cells,highlighting their specificity and therapeutic potential in antigen-directed applications.Conclusions:We successfully established a CD8-targeting exosome delivery system for CAR-T cell production capable of transforming CD8+T cells into functional CAR-T cells,which showed significant tumor-killing ability in vitro and in mice.Compared with the traditional lentiviral vector for the preparation of CAR-T cells in vitro,in vivo-reprogrammed CAR-T cells us-ing our CD8-targeted exosome delivery system,with higher transfection efficiency,shorter production period,lower cost,and eliminated the risk of insertion carcinogenesis.This strategy promises to bring a new era of universal CAR-T medicine,which can improve cancer immuno-therapy and may hold promise as a therapeutic platform to treat various diseases.
6.Effects and mechanisms of high-dose glucocorticoids on senescence, apoptosis, and osteogenic differentiation of bone marrow mesenchymal stem cells
Zhendong YING ; Changjun CHEN ; Dailing CHEN ; Qiuru WANG ; Qibin LIU ; Qingwei MA ; Lei ZHANG ; Pengde KANG ; Xin ZHAO
Chinese Journal of Orthopaedics 2025;45(18):1208-1216
Objective:To elucidate the molecular mechanisms through which high-dose dexamethasone exerts long-term effects on bone marrow mesenchymal stem cells (BMSCs), specifically its role in suppressing osteogenic differentiation, accelerating cellular senescence, triggering the senescence-associated secretory phenotype (SASP), and inducing apoptosis.Methods:Primary rat BMSCs were isolated and treated with high-dose dexamethasone (1×10 -4 mol/L) to establish the experimental group, while untreated cells served as the control. The gene and protein expression levels of osteogenic markers, bone alkaline phosphatase (bALP) and Runt-related transcription factor 2 (Runx2), were analyzed in both groups. Cellular senescence was evaluated using senescence-associated β-galactosidase (SA-β-gal) staining. The expression of senescence-related markers (P16 and P21), components of the senescence-associated secretory phenotype (SASP), including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and interferon (IFN)-γ, as well as apoptosis-related proteins (Bcl-2, Bax, and Cleaved-Caspase-3), and key factors of the Nrf2/HO-1 signaling pathway were assessed at both transcriptional and protein levels using qRT-PCR, immunofluorescence, and Western-blot analyses. These comprehensive evaluations aimed to determine the senescent state, apoptotic features, and alterations in osteogenic differentiation of BMSCs. Results:Following treatment with dexamethasone and subsequent withdrawal, both qRT-PCR and Western blot analyses indicated a significant reduction in the expression of the osteogenic markers bALP and Runx2 at both mRNA and protein levels. The proportion of SA-β-gal positive cells was markedly higher in the dexamethasone group (74.33%±6.89%) than in the control group (20.30%±1.57%, t=17.300, P<0.001). qRT-PCR analysis revealed upregulated mRNA expression of the senescence-related genes P16 and P21 after dexamethasone treatment, which was further supported at the protein level by immunofluorescence showing increased P21 expression. Western-blot results confirmed that protein expression levels of P16 and P21 were significantly elevated in the dexamethasone group (7.025±0.255 and 6.362±0.456, respectively) compared with the control group (1.016±0.115 and 0.816±0.172; both P<0.05). Furthermore, gene expression levels of the senescence-associated secretory phenotype (SASP) factors TNF-α and IL-1β were significantly increased (TNF-α: 3.539±0.599 vs. 0.742±0.095; IL-1β: 4.469±0.331 vs. 0.799±0.175; both P<0.05), and their protein expression was consistently upregulated as validated by Western-blot. Additionally, protein expression levels of TNF-α, IL-1β, and IFN-γ were significantly higher in the dexamethasone-treated group (3.476±0.932 vs. 0.945±0.095; 4.111±0.220 vs. 0.762±0.105; 2.155±0.240 vs. 0.656±0.104; all P<0.05).Western-blot analysis also demonstrated that protein expression of Nrf2 and HO-1 was significantly suppressed in the dexamethasone group (0.21±0.07 and 0.19±0.06, respectively) compared with the control group (1.13±0.15 and 0.92±0.21; P<0.05). Moreover, Western-blot analysis revealed that the expression levels of the pro-apoptotic proteins Bax and Cleaved-Caspase-3 were significantly up, regulated in the dexamethasone, treated BMSCs (Bax: 3.673±0.397 vs. 0.453±0.111; Cleaved-Caspase-3: 3.863±0.399 vs. 0.465±0.057), while the expression of the anti-apoptotic protein Bcl-2 was markedly down, regulated (0.959±0.073 vs. 2.126±0.195), with all differences being statistically significant ( P<0.05). Conclusions:High-dose dexamethasone treatment of BMSCs, followed by withdrawal of dexamethasone, induces cellular senescence and enhances the expression of the senescence-associated secretory phenotype (SASP) through suppression of the Nrf2/HO-1 signaling pathway. Concurrently, it promotes apoptosis by activating the mitochondrial apoptotic pathway, collectively leading to impaired osteogenic differentiation of BMSCs.
7.In vivo production of anti-CD19 CAR-T cells with T cell-targeted engineered exosomes to evaluate cytotoxicity against lymphoma cells
Dong TING ; Zhou YING ; Yu BOYU ; Xia XUEJIAO ; Ma YIGE ; Ma YAN ; Gao YANG ; Zhou MENGYING ; Wang CHANGJUN ; Li QIUYI ; Gu CHAOJIANG
Chinese Journal of Clinical Oncology 2025;52(6):279-286
Objective:Chimeric antigen receptor T-cell(CAR-T)immunotherapy has made major breakthroughs in the treatment of blood tu-mors.However,current CAR-T therapies face several limitations:they require autologous cells,involve a lengthy and costly production pro-cess,and use lentiviral transduction that carry risk of insertional carcinogenesis due to random integration.Therefore,there is an urgent need to develop a universal cost-effective cancer immunotherapy method generating CAR-T cells for in vivo cancer immunotherapy.Meth-ods:This study successfully established an exosome-mediated,T-cell targeted delivery system,demonstrating both precise design and func-tional efficacy for biomedical applications.To optimize CAR-T cell generation the transfection dose was adjusted,and the kinetics of CAR-T cell percentage were recorded.The cytotoxicity of the resulting CAR-T cells was evaluated in vitro by calcein-AM release.To test the tumor-killing in vivo of engineered exosomes,human PBMCs were injected into NPG mice via the tail vein to establish humanized mice,followed by intravenous injection of tumor cells to induce cancer.Results:To overcome the limitations of conditional autologous CAR-T cells,we de-veloped a T cell-targeted exosome system capable of specifically targeting human CD3+,CD4+,and CD8+T cells.CAR-T production was dose-dependent,with transfection efficiency reaching upto 97.8%at 106 particles/cell.Both in vitro cytotoxicity assays and in vivo animal experi-ments demonstrated that exosome-incubated CAR-T cells effectively eliminated CD19-positive Raji cells,highlighting their specificity and therapeutic potential in antigen-directed applications.Conclusions:We successfully established a CD8-targeting exosome delivery system for CAR-T cell production capable of transforming CD8+T cells into functional CAR-T cells,which showed significant tumor-killing ability in vitro and in mice.Compared with the traditional lentiviral vector for the preparation of CAR-T cells in vitro,in vivo-reprogrammed CAR-T cells us-ing our CD8-targeted exosome delivery system,with higher transfection efficiency,shorter production period,lower cost,and eliminated the risk of insertion carcinogenesis.This strategy promises to bring a new era of universal CAR-T medicine,which can improve cancer immuno-therapy and may hold promise as a therapeutic platform to treat various diseases.
8.Study on the role of aerobic exercise in regulating the CNPY2-mediated AKT/GSK3β pathway for improving non-alcoholic fatty liver
Jiaqian WANG ; Changjun JIANG ; Yi PENG ; Mi MA ; Junhan LI
Chinese Journal of Tissue Engineering Research 2025;29(30):6441-6448
BACKGROUND:Non-alcoholic fatty liver disease is one of the common chronic liver diseases in the world.Aerobic exercise is considered to be an important means for the treatment of non-alcoholic fatty liver disease.However,the mechanism of exercise to improve non-alcoholic fatty liver disease has not been fully clarified.OBJECTIVE:To investigate the effects of aerobic exercise on the protein kinase B/glycogen synthase kinase-3β pathway mediated by Canopy FGF signaling regulator 2(CNPY2)in the liver canopy of non-alcoholic fatty liver disease mice and its mechanism.METHODS:Thirty male CNPY2 knockout mice(ko)and thirty their litters of wild-type mice(wt)were fed adaptively for one week and randomly divided into control group,model group,and model exercise group,with 10 mice in each group.The control group was fed with ordinary diet.The model group and the model exercise group were fed with high-fat diet for 17 weeks.The model exercise group received continuous aerobic exercise intervention from week 10 until the end of the experiment at week 18.Liver histopathology was observed by hematoxylin-eosin and oil red O staining.The levels of serum lipids and liver function were detected by automatic biochemical analyzer.The expression levels of CNPY2,protein kinase B/glycogen synthase kinase-3β pathway,and Caspase-3 protein in liver tissues were detected by Western Blotting.The apoptosis rate of hepatocytes was detected by TUNEL staining.RESULTS AND CONCLUSION:(1)Compared with wt control group,CNPY2 expression in liver tissues of wt model group was increased(P<0.05),while CNPY2 expression in wt model exercise group was decreased compared with wt model group(P<0.05).Compared with control group,wt mice and ko mice in model group showed steatosis,increased lipid droplets,abnormal blood lipids and liver function,decreased protein kinase B/glycogen synthase kinase-3β expression(P<0.05)and increased Caspase-3 expression(P<0.05),and increased hepatocyte apoptosis rate in liver tissue(P<0.05).(2)Compared with the model group,wt mice and ko mice showed improvement in the above indexes in model exercise group.(3)Compared with wt mice,the above indexes of ko mice were improved.(4)These findings indicate that CNPY2 gene deletion and aerobic exercise can effectively improve non-alcoholic fatty liver disease.The mechanism may be related to aerobic exercise reducing CNPY2 expression,activating protein kinase B/glycogen synthase kinase-3β signaling pathway,and thus inhibiting hepatocyte apoptosis.
9.Study on the role of aerobic exercise in regulating the CNPY2-mediated AKT/GSK3β pathway for improving non-alcoholic fatty liver
Jiaqian WANG ; Changjun JIANG ; Yi PENG ; Mi MA ; Junhan LI
Chinese Journal of Tissue Engineering Research 2025;29(30):6441-6448
BACKGROUND:Non-alcoholic fatty liver disease is one of the common chronic liver diseases in the world.Aerobic exercise is considered to be an important means for the treatment of non-alcoholic fatty liver disease.However,the mechanism of exercise to improve non-alcoholic fatty liver disease has not been fully clarified.OBJECTIVE:To investigate the effects of aerobic exercise on the protein kinase B/glycogen synthase kinase-3β pathway mediated by Canopy FGF signaling regulator 2(CNPY2)in the liver canopy of non-alcoholic fatty liver disease mice and its mechanism.METHODS:Thirty male CNPY2 knockout mice(ko)and thirty their litters of wild-type mice(wt)were fed adaptively for one week and randomly divided into control group,model group,and model exercise group,with 10 mice in each group.The control group was fed with ordinary diet.The model group and the model exercise group were fed with high-fat diet for 17 weeks.The model exercise group received continuous aerobic exercise intervention from week 10 until the end of the experiment at week 18.Liver histopathology was observed by hematoxylin-eosin and oil red O staining.The levels of serum lipids and liver function were detected by automatic biochemical analyzer.The expression levels of CNPY2,protein kinase B/glycogen synthase kinase-3β pathway,and Caspase-3 protein in liver tissues were detected by Western Blotting.The apoptosis rate of hepatocytes was detected by TUNEL staining.RESULTS AND CONCLUSION:(1)Compared with wt control group,CNPY2 expression in liver tissues of wt model group was increased(P<0.05),while CNPY2 expression in wt model exercise group was decreased compared with wt model group(P<0.05).Compared with control group,wt mice and ko mice in model group showed steatosis,increased lipid droplets,abnormal blood lipids and liver function,decreased protein kinase B/glycogen synthase kinase-3β expression(P<0.05)and increased Caspase-3 expression(P<0.05),and increased hepatocyte apoptosis rate in liver tissue(P<0.05).(2)Compared with the model group,wt mice and ko mice showed improvement in the above indexes in model exercise group.(3)Compared with wt mice,the above indexes of ko mice were improved.(4)These findings indicate that CNPY2 gene deletion and aerobic exercise can effectively improve non-alcoholic fatty liver disease.The mechanism may be related to aerobic exercise reducing CNPY2 expression,activating protein kinase B/glycogen synthase kinase-3β signaling pathway,and thus inhibiting hepatocyte apoptosis.
10.Effects and mechanisms of high-dose glucocorticoids on senescence, apoptosis, and osteogenic differentiation of bone marrow mesenchymal stem cells
Zhendong YING ; Changjun CHEN ; Dailing CHEN ; Qiuru WANG ; Qibin LIU ; Qingwei MA ; Lei ZHANG ; Pengde KANG ; Xin ZHAO
Chinese Journal of Orthopaedics 2025;45(18):1208-1216
Objective:To elucidate the molecular mechanisms through which high-dose dexamethasone exerts long-term effects on bone marrow mesenchymal stem cells (BMSCs), specifically its role in suppressing osteogenic differentiation, accelerating cellular senescence, triggering the senescence-associated secretory phenotype (SASP), and inducing apoptosis.Methods:Primary rat BMSCs were isolated and treated with high-dose dexamethasone (1×10 -4 mol/L) to establish the experimental group, while untreated cells served as the control. The gene and protein expression levels of osteogenic markers, bone alkaline phosphatase (bALP) and Runt-related transcription factor 2 (Runx2), were analyzed in both groups. Cellular senescence was evaluated using senescence-associated β-galactosidase (SA-β-gal) staining. The expression of senescence-related markers (P16 and P21), components of the senescence-associated secretory phenotype (SASP), including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and interferon (IFN)-γ, as well as apoptosis-related proteins (Bcl-2, Bax, and Cleaved-Caspase-3), and key factors of the Nrf2/HO-1 signaling pathway were assessed at both transcriptional and protein levels using qRT-PCR, immunofluorescence, and Western-blot analyses. These comprehensive evaluations aimed to determine the senescent state, apoptotic features, and alterations in osteogenic differentiation of BMSCs. Results:Following treatment with dexamethasone and subsequent withdrawal, both qRT-PCR and Western blot analyses indicated a significant reduction in the expression of the osteogenic markers bALP and Runx2 at both mRNA and protein levels. The proportion of SA-β-gal positive cells was markedly higher in the dexamethasone group (74.33%±6.89%) than in the control group (20.30%±1.57%, t=17.300, P<0.001). qRT-PCR analysis revealed upregulated mRNA expression of the senescence-related genes P16 and P21 after dexamethasone treatment, which was further supported at the protein level by immunofluorescence showing increased P21 expression. Western-blot results confirmed that protein expression levels of P16 and P21 were significantly elevated in the dexamethasone group (7.025±0.255 and 6.362±0.456, respectively) compared with the control group (1.016±0.115 and 0.816±0.172; both P<0.05). Furthermore, gene expression levels of the senescence-associated secretory phenotype (SASP) factors TNF-α and IL-1β were significantly increased (TNF-α: 3.539±0.599 vs. 0.742±0.095; IL-1β: 4.469±0.331 vs. 0.799±0.175; both P<0.05), and their protein expression was consistently upregulated as validated by Western-blot. Additionally, protein expression levels of TNF-α, IL-1β, and IFN-γ were significantly higher in the dexamethasone-treated group (3.476±0.932 vs. 0.945±0.095; 4.111±0.220 vs. 0.762±0.105; 2.155±0.240 vs. 0.656±0.104; all P<0.05).Western-blot analysis also demonstrated that protein expression of Nrf2 and HO-1 was significantly suppressed in the dexamethasone group (0.21±0.07 and 0.19±0.06, respectively) compared with the control group (1.13±0.15 and 0.92±0.21; P<0.05). Moreover, Western-blot analysis revealed that the expression levels of the pro-apoptotic proteins Bax and Cleaved-Caspase-3 were significantly up, regulated in the dexamethasone, treated BMSCs (Bax: 3.673±0.397 vs. 0.453±0.111; Cleaved-Caspase-3: 3.863±0.399 vs. 0.465±0.057), while the expression of the anti-apoptotic protein Bcl-2 was markedly down, regulated (0.959±0.073 vs. 2.126±0.195), with all differences being statistically significant ( P<0.05). Conclusions:High-dose dexamethasone treatment of BMSCs, followed by withdrawal of dexamethasone, induces cellular senescence and enhances the expression of the senescence-associated secretory phenotype (SASP) through suppression of the Nrf2/HO-1 signaling pathway. Concurrently, it promotes apoptosis by activating the mitochondrial apoptotic pathway, collectively leading to impaired osteogenic differentiation of BMSCs.

Result Analysis
Print
Save
E-mail