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.

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

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.

Objective To investigate the effect of different excipients of propofol on blood lipids and liver function during orthotopic liver transplantation. Methods Forty ASA Ⅲ- Ⅳ patients aged 40-64 yr weighing 50-75 kg undergoing orthotopic liver transplantation were randomly divided into 2 groups ( n = 20 each): propofol medium-chain triglycerides/long-chain triglycerides (MCT/LCT) group (group M) and propofol LCT group (group L). Anesthesia was induced with penehyclidine 1 mg, midazolam 0.04-0.06 mg/kg, sufentanil 0.6-0.8 μg/kg and propofol 1.5-2.0 mg/kg. Tracheal intubation was facilitated with vecuronium 0.10-0.15 mg/kg. The patients were mechanically ventilated. Anesthesia was maintained with 1%-2% isoflurane, continuous infusion of propofol blood samples were collected after admission into the operation room (T1), before skin incision (T2), at the end of pre-anhepatic phase (T3), at the end of anhepatic phase (T4) and 30 and 240 min of neohepatic phase (T5, T6 )for determination of plasma concentrations of triglyceride (TG), total cholesterol (CH), high-density-lipoproteincholesterol (HDL-C), low density-lipoprotein-cholesterol (LDL-C), and activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The changes in parameters from baseline values were calculated. Results Compared with group L, △TG was significant1y decreased at T4-6 in group M ( P ＜ 0.05 ) . There was no significant difference in △CH, △HDL-C, △LDL-C, △AST and △ALT,plasma concentrations of TG,CH, HDL-C and LDL-C,and activities of AST and ALT between the two groups ( P ＞ 0.05). Conclusion The effect of the two formulations of propofol on liver function is comparable. Propofol MCT/LCT exerts less effect on blood lipids during liver transplantation and is more suitable for this type of surgery.