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Oxysophocarpine (OSC), a quinolizidine alkaloid, shows neuroprotective potential, though its mechanisms are unclear. The aim of the present study was to investigate the neuroprotective effects of OSC through the nuclear factor erythroid 2−related factor 2 (Nrf2)/ heme oxygenase−1 (HO–1) signaling pathway using the HT–22 cell line. Assessments of cell viability were conducted utilizing the 3−(4,5−dimethylthiazol−2−yl)−2,5−diphenyltetrazolium bromide (MTT) assay. Assessments of oxidative stress (OS) were conducted through the quantification of reactive oxygen species (ROS). The integrity of the mitochondrial membrane potential (MMP) was scrutinized using fluorescent probe technology. Apoptosis levels were quantified using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The trafficking of Nrf2 within the cell nucleus was examined through immunofluorescence analysis. Furthermore, Western blotting (WB) was applied to evaluate the expression levels of proteins implicated in apoptosis and the Nrf2/HO–1 pathway. To further probe the influence of OSC on the overexpression of antioxidant enzymes, cells were subjected to transfection with HO–1 siRNA. The results showed that OSC inhibited glutamate-induced OS, as evidenced by reduced cell viability and ROS levels. Furthermore, the apoptotic condition induced by glutamate in HT–22 cells was significantly reduced following OSC treatment. More interestingly, the Nrf2/HO–1 signaling pathway was upregulated following OSC treatment. These results suggest that OSC can exert neuroprotective effects by regulating the Nrf2/HO–1 pathway to inhibit neuronal cell apoptosis, potentially aiding in the treatment of neurodegenerative diseases.

Artemisia japonica Thunb. has been used as a traditional Chinese medicine and a vegetable for thousands of years in China. However, there are few reports on the chemical composition and biological activity of its leaves. Thus, this study aimed to evaluate the chemical composition, antioxidant and anti-inflammatory effects of water extracts of A. japonica leaves and their underlying mechanisms. A total of 48 compounds were identified in the water extract using UPLC-QTOF-MS2 analysis, with phenolic acids, particularly chlorogenic acid compounds, being the predominant components. The ethyl acetate fraction (EAF) contained most of the total phenolic content (385.4217 mg GAE/g) and displayed superior antioxidant capacity with the IC50DPPH•, IC50ABTS•+, and OD0.5reducing power at 10.987 μg/mL, 43.630 μg/mL and 26.883 μg/mL, respectively. Furthermore, EAF demonstrated potent antioxidant and anti-inflammatory effects in LPS-induced RAW264.7 cells by upregulating the Nrf2/HO-1 signal pathway. These findings highlight that A. japonica leaves possess remarkable abilities to mitigate inflammation and oxidative stress, suggesting their potential utilization as medicinal agents and food additives for promoting human health. [ABSTRACT FROM AUTHOR]

Objective To investigate the effect and its mechanism of emodin on the ferroptosis of chondrocytes in rats with knee osteoarthritis (KOA). Methods A total of 96 SD rats were divided into the sham operation (sham) group, the KOA group, the emodin (EMO) group and the emodin+Nrf2 inhibitor (EMO+ML385) group, with 24 rats in each group. Except for the sham group, KOA rat models were established by modified Hulth method in each group. The tumor necrosis factor-α (TNF-α), nitric oxide (NO) and prostaglandin E2 (PGE2) levels were detected by enzyme-linked immunosorbent assay (ELISA). General morphology of knee joint was observed with naked eyes. The pathological morphology of knee joint cartilage was observed with safranine O-solid green staining. Apoptosis rate of chondrocytes of knee joint was detected by TdT-mediated dUTP nick end labeling (TUNEL) staining. Malondialdehyde (MDA), reactive oxygen species (ROS), glutathione (GSH) and ferrous ion (Fe2+) levels in knee joint cartilage were detected by biochemical reagent kit. Expression levels of matrix metalloproteinase (MMP)-3, MMP-13, collagen type II α1 (COL2A1), prostaglandin-endoperoxide synthase 2 (PTGS2), glutathione peroxidase 4 (GPX4), acyl-CoA synthetase long chain family member 4 (ACSL4), nuclear factor E2- related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) mRNA or protein in knee joint cartilage were detected by real-time fluorescence quantitative PCR (qRT-PCR), Western blot assay or immunohistochemistry. Results Compared with the sham group, the serum TNF-α, NO and PGE2 levels, Osteoarthritis Research Society International (OARSI) score, apoptosis rate, mRNA expression of MMP-3, MMP-13 and PTGS2, MDA, ROS, and Fe2+ levels, proportion of ACSL4 positive cells, and protein expression of ACSL4, nuclear Nrf2 and HO-1 increased in the KOA group. GSH levels, mRNA expression of COL2A1, proportion of GPX4 positive cells, and protein expression of GPX4 and cytoplasmic Nrf2 decreased (P<0.05). The articular cartilage was obviously damaged. EMO can improve the inflammatory reaction, knee joint cartilage tissue injury and chondrocyte ferroptosis of KOA rats, and further activate Nrf2/HO-1 signal pathway. ML385 not only inhibited the activation of Nrf2/HO-1 signal pathway, but also attenuated the improvement of EMO on knee joint cartilage tissue injury and chondrocyte ferroptosis of KOA rats. Conclusion Emodin can activate Nrf2/HO-1 signal pathway, inhibit chondrocyte ferroptosis and protect knee articular cartilage of KOA rats. [ABSTRACT FROM AUTHOR]

Objective: Periostin is important for the maintenance of periodontal tissue, but its role in periodontitis is controversial. This research investigated the effect of periostin in periodontitis and the underlying mechanism. Design: Mouse periodontitis models in vivo and inflammation model in vitro which were induced by Porphyromonas gingivalis lipopolysaccharide were established to evaluate periostin expression. Human periodontal ligament fibroblasts (PDLFs) were treated with lipopolysaccharide and N‐acetylcysteine, fluorescence staining, flow cytometry, Western blot, and qRT‐PCR were used to detect reactive oxygen species (ROS), periostin expression, and apoptosis‐related makers. The periostin gene was successfully transfected into PDLFs to verify the effect of periostin on apoptosis. Then, the Nrf2 inhibitor was added to clarify the mechanism. Results: Periostin expression decreased in the periodontal ligaments of mouse periodontitis models and lipopolysaccharide‐induced PDLFs. Lipopolysaccharide promoted the activation of ROS and apoptosis in PDLFs, whereas N‐acetylcysteine reversed this condition. Overexpression of periostin suppressed apoptosis of PDLFs and reversed the inhibitory effect of lipopolysaccharide on nuclear Nrf2 expression. Moreover, the Nrf2 inhibitor attenuated the protective effect of periostin on lipopolysaccharide‐induced apoptosis. Conclusions: Lipopolysaccharide induced apoptosis in PDLFs by inhibiting periostin expression and thus Nrf2/HO‐1 pathway, indicating that periostin could be a potential therapeutic target for periodontitis. [ABSTRACT FROM AUTHOR]

The pericarp of Zanthoxylum bungeanum maxim (PZM) is a commonly used spice and herbal medicine in China. In the present study, the structural characteristics of PPZM were investigated by saccharide mapping after enzymatic digestion by using high-performance thin layer chromatography (HPTLC) and polysaccharide analysis by using carbohydrate gel electrophoresis (PACE). The mechanisms of protective effects of PPZM on Aβ25–35-induced oxidative damage were explored in PC12 cells. The results showed that PPZM contained 1,4-α-D-galactosidic, 1,4-α-D-galactosiduronic, and (1→4)-β-D-glucosidic linkages. Pretreatment with PPZM significantly increased the cell viability of Aβ25–35-injured PC12 cells. Flow cytometry and Hoechst/PI staining indicated that PPZM gradually relieved the apoptosis of the Aβ25–25-treated cells. PPZM markedly decreased the ROS level of PC12 cells and suppressed Aβ25–35-induced oxidative stress by increasing the SOD level, and decreasing the level of MDA and LDH. The mRNA expressions of caspase-3 and Bax were significantly downregulated, and Bcl-2 expression was upregulated by treatment with PPZM. PPZM significantly increased the mRNA expression of Nrf2 and HO-1 in Aβ25–35 treated cells. The results indicated that PPZM alleviated apoptosis and oxidative stress induced by Aβ25–25 through the inhibition of mitochondrial dependent apoptosis and activation of Nrf2/HO-1 pathway. PPZM can be used as a potential protective agent against Aβ25–25-induced neurotoxicity. [ABSTRACT FROM AUTHOR]

Oxidative stress is closely linked to the etiology of temporomandibular joint osteoarthritis. (TMJ-OA) and is an important therapeutic target. Cerium oxide nanoparticles (CNPs) have been broadly studied owing to their powerful antioxidant properties and potential preventive and therapeutic effects against chronic diseases. The current study was designed to explore the protective effects of CNPs on the progression of TMJ-OA and their potential mechanisms. We detected the ability of CNPs to eliminate reactive oxygen species (ROS) in chondrocytes. Moreover, their protective effects on chondrocytes were detected in the level of gene and protein. Furthermore, TUNEL assay, histology and safranin O-fast green staining were used to detect the beneficial effects of CNPs on cartilage explants. The mechanism of CNPs, protecting condylar cartilage by reducing inflammation, was further explored by knocking down the Nuclear factor-erythroid 2-related factor (Nrf2) gene. CNPs could reduce the ROS levels in chondrocytes and cartilage explants and reverse the IL-1β-induced imbalance of cartilage matrix metabolism and apoptosis. The protective effects of CNPs on cartilage were lost after key antioxidant factors including Nrf2 and heme-oxygenase 1(HO-1) were significantly reduced. In conclusion, this study demonstrated for the first time that activating the Nrf2/HO-1 signaling pathway by CNPs might have therapeutic potential for TMJ-OA.

Spinal cord injury (SCI) often induces severe sensory and motor dysfunction. Oxidative stress is an important pathophysiological process of secondary SCI, and its inhibition could facilitate the alleviation of the injury. Resveratrol is a natural plant polyphenol compound that has significant antioxidant and anti-inflammatory effects. It can inhibit oxidative stress by activating the Nrf2/HO-1 signal pathway. In this report, we analyze the antioxidant effect of resveratrol in SCI, clarify the specific mechanism of action and provide a theoretical basis for the clinical employment of resveratrol for SCI. [Display omitted] [ABSTRACT FROM AUTHOR]