Fei-Hu Chen

Protective effects of total flavonoids of Bidens pilosa L. (TFB) on animal liver injury and liver fibrosis

The hepatoprotective effects of total flavonoids of Bidens pilosa L. (TFB), a traditional Chinese medicine were evaluated in carbon tetrachloride (CCl(4))-induced liver injury in mice and rats. Total flavonoids of Bidens pilosa L. (25, 50 and 100mg/kg) were administered via gavage daily for 10 days to CCl(4)-treated mice as well as TFB (30, 60 and 90mg/kg) administered for 6 weeks to CCl(4)-treated rats. Liver index (liver weight/body weight), serum levels of transaminases (alanine aminotransferase, ALT and aspartate aminotransferase, AST), hepatic malondialdehyde (MDA) content, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were evaluated following the 10 days treatment in mice. In addition histopathologic changes and nuclear factor-kappaB (NF-kappaB) expression of the liver were detected with hematoxylin-eosin (HE) and immunohistochemistry methods, respectively. The results showed that TFB (50 and 100mg/kg) effectively reduced the CCl(4)-induced elevated liver index, serum ALT, AST levels, hepatic MDA content, and restored hepatic SOD, GSH-Px activities in acute liver injury mice. TFB (60 and 90mg/kg) treatment significantly inhibited NF-kappaB activation in liver fibrosis of rats. The histopathological analysis suggested that TFB reduced the degree of liver injury in mice and severity of liver fibrosis in rats. These results suggested that TFB had a protective and therapeutic effect on animal liver injury, which might be associated with its antioxidant properties and inhibition of NF-kappaB activation.

Acid-sensing ion channel 1a mediates acid-induced increases in intracellular calcium in rat articular chondrocytes.

Acid-sensing ion channels (ASICs) are cationic channels that are activated by extracellular acidification and implicated in pain perception, ischemic stroke, mechanosensation, learning, and memory. It has been shown that ASIC1a is an extracellular pH sensor in the central and peripheral nervous systems, but its physiological and pathological roles in non-neural cells are poorly understood. We demonstrated a novel physiological function of ASIC1a in rat articular chondrocytes. The expression of ASIC1a mRNA and protein in rat articular chondrocytes was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting. The distribution of ASIC1a protein located in articular chondrocytes was determined by using immunofluorescence cell staining. The possible molecular mechanisms of articular chondrocytes pH sensing, as assessed by recording intracellular calcium ([Ca2+]i) in chondrocytes, were analyzed by using the laser scanning confocal microscopy technique. The cell injure following acid exposure was analyzed with lactate dehydrogenase release assay and electron microscopy. mRNA and protein expression showed that ASIC1a was expressed abundantly in these cells. In cultured chondrocytes, extracellular pH 6.0 increased intracellular calcium in the presence of extracellular Ca2+. The ASIC1a-specific blocker PcTX venom significantly reduced this increase in [Ca2+]i, and inhibited acid-induced articular chondrocyte injury. However, the increase in [Ca2+]i and articular chondrocyte injury were not observed in the absence of extracellular Ca2+. These findings show that increased [Ca2+]i, mediated via ASIC1a, might contribute to acidosis-induced articular chondrocyte injury.

Targeting interleukin-21 in rheumatoid arthritis

Interleukin-21 (IL-21) is a new member of the type I cytokine superfamily, which binds to a composite receptor that consists of a private receptor (IL-21R) and the common cytokine receptor γ chain. Recently, increasing evidence has shown that IL-21 contributes to the pathogenesis of chronic inflammatory and autoimmune diseases because of its pro-inflammatory and immune-mediated properties. IL-21 induced T-cell activation and pro-inflammatory cytokine secretion in rheumatoid arthritis (RA). IL-21R RNA transcripts were found in synovial tissue samples of patients with RA. In addition, blockade of the IL-21/IL-21R pathway ameliorated disease in animal models of RA and significantly inhibited inflammatory cytokine production in vitro. Moreover, IL-21R deficiency in the K/BxN mouse model of inflammatory arthritis was sufficient to block arthritis initiation completely. All theses findings suggest that IL-21 has important biological effects in autoimmunity that might be a promising therapeutic target for RA. In this review, we discuss the biological features of IL-21 and summarize recent advances in the role of IL-21 in the pathogenesis and treatment of RA.

Blockade of acid-sensing ion channels protects articular chondrocytes from acid-induced apoptotic injury

ObjectiveAcid-sensing ion channels (ASICs) are members of the degenerin/epithelial sodium channel (DEG/ENaC) protein superfamily and play a critical role in acid-induced cell injury. In this study, we examined whether drugs such as amiloride that block ASICs could attenuate acid-induced apoptotic injury to articular chondrocytes.MethodsArticular chondrocytes were isolated from Sprague–Dawley rats, and their phenotype was determined by toluidine blue and immunocytochemical staining. Articular chondrocyte viability assay was performed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). Apoptosis of chondrocytes was observed by the terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling method as well as propidium iodide labeling methods. Intracellular calcium ([Ca2+]i) was analyzed by a Ca2+-imaging method. In addition, the expression levels of calpain and calcineurin in articular chondrocytes were examined by real-time PCR and immunocytochemical staining. The activity of caspase-3 was evaluated by spectrophotometric assays.ResultsPositive staining for glycosaminoglycan and collagen II was seen in articular chondrocytes. Blocking acid-sensing ion channels significantly decreased the cell death percentage and increased cell viability following acid exposure. After pretreated with amiloride, acid-induced [Ca2+]i rises were reduced. Amiloride also inhibited calpain and calcineurin expression levels in acid-induced chondrocytes, and inhibited caspase-3 activity.ConclusionThe data presented in this study provided some experimental evidence that blocking ASICs could protect acid-induced apoptotic injury to chondrocytes.

Protective effects of total flavonoids of Bidens bipinnata L. against carbon tetrachloride-induced liver fibrosis in rats.

Bidens bipinnata L. is well known in China as a traditional Chinese medicine and has been used to treat hepatitis in clinics for many years. In a previous study we found that total flavonoids of Bidens bipinnata L. (TFB) had a protective effect against carbon tetrachloride (CCl4)-induced acute liver injury in mice. Now this study was designed to investigate its therapeutic effect against CCl4-induced liver fibrosis in rats and to determine, in part, its mechanism of action. The liver fibrosis model was established by subcutaneous injection of 50% CCl4 twice a week for 18 weeks. TFB (40, 80 and 160 mg kg(-1)) was administered by gastrogavage daily from the 9th week. The results showed that TFB (80 and 160 mg kg(-1)) treatment for 10 weeks significantly reduced the elevated liver index (liver weight/body weight) and spleen index (spleen weight/body weight), elevated levels of serum transaminases (alanine aminotransferase and aspartate aminotransferase), hyaluronic acid, type III procollagen and hepatic hydroxyproline. In addition, TFB markedly inhibited CCl4-induced lipid peroxidation and enhanced the activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase. Moreover, TFB (80 and 160 mg kg(-1)) treatment improved the morphologic changes of hepatic fibrosis induced by CCl4 and suppressed nuclear factor (NF)-kappaB, alpha-smooth muscle actin (SMA) protein expression and transforming growth factor (TGF)-beta1 gene expression in the liver of liver fibrosis of rats. In conclusion, TFB was able to ameliorate liver injury and protect rats from CCl4-induced liver fibrosis by suppressing oxidative stress. This process may be related to inhibiting the induction of NF-kappaB on hepatic stellate cell activation and the expression of TGF-beta1.

Regulatory T cells as a potent target for controlling bone loss.

Metabolic bone diseases, such as rheumatoid arthritis (RA) and osteoporosis, affect hundreds and millions of people worldwide leading causes of long-term pain and disability. Effective clinical treatment for bone destruction in bone diseases is lacking because the knowledge about molecular mechanisms leading to bone destruction are incompletely understood. Recently, it has been confirmed that regulatory T cells (Tregs) play a crucial role in suppressing the immune response in the pathogenesis of various autoimmune diseases. In vitro, Tregs directly inhibit osteoclasts and differentiation and function. In mice, the injection of Tregs into the TNF transgenic results in enhanced systemic bone density. In addition, it has been shown that increase of Tregs numbers by overexpressing the FoxP3 is effective in the prevention of local and systemic bone destruction. In vivo treatment with anti-CD28 superagonist antibody leading to a stronger increase in Tregs numbers protect against TNF-a-induced bone loss in TNF-transgenic mice. In agreement, Tregs can control ovariectomy-induced bone loss in FoxP3-transgenic mice. In this paper, we will briefly discuss the biological features of Tregs and summarize recent advances on the role of Tregs in the pathogenesis and treatment of bone loss in metabolic bone diseases.

Antidepressant-like effect of resveratrol: Involvement of antioxidant effect and peripheral regulation on HPA axis

This study focused on exploring the antidepressant potential of resveratrol (RES) and its possible mechanisms of action. Cell injury was induced by corticosterone (CORT) and detected through cell viability and contents of lactate dehydrogenase (LDH) and malonaldehyde (MDA). A rat model of depression was established through 3weeks of consecutive chronic unpredictable mild stress (CUMS), and both the depression-like behaviors and the activity of the hypothalamic-pituitary-adrenal (HPA) axis were tested. Apart from the inhibitory effect on MDA production in vitro and in vivo, the results showed that RES (10(-10)mol/L to 10(-5)mol/L) could significantly increase the cell viability and decrease the LDH activity and that RES (15mg/kg) treatment could alleviate the depression-like behavior of CUMS rats, as indicated by increased sucrose preference and decreased immobility in forced swimming test and tail suspension test. Rats that received RES treatment displayed a reduction of serum CORT, suggesting that RES affected the hyperactivity of the HPA axis in CUMS rats. However, RES did not affect the expression of corticotropin-releasing hormone (CRH) mRNA in the hypothalamus of CUMS rats. In summary, our results demonstrated that in addition to its widely known antioxidant properties, RES also has antidepressant-like effects, and suggested that the underlying mechanism might involve its peripheral effect on the regulation of the HPA axis.

Orcinol glucoside produces antidepressant effects by blocking the behavioural and neuronal deficits caused by chronic stress

This study focused on the antidepressant potential of orcinol glucoside (OG) and its possible mechanisms of action. We established a depressed rat model using 3 consecutive weeks of chronic unpredictable mild stress (CUMS). The antidepressant-like effect of OG was revealed using the sucrose preference test, the open field test, the forced swimming test (FST), and the tail suspension test (TST). The activity of the hypothalamic-pituitary-adrenal (HPA) axis was evaluated by detecting the serum corticosterone (CORT) concentrations and mRNA expression of corticotrophin-releasing hormone (CRH) in the hypothalamus. The protein expression levels of brain-derived neurotrophic factor (BDNF) and total phosphorylated-ERK1/2 were detected by western blot. The results showed that OG treatment (1.5, 3, or 6mg/kg) alleviated the depression-like behaviour of rats under CUMS, as indicated by the increased sucrose preference and the decreased immobility in both the FST and TST, although the rearing frequency in the open field test increased only in the group that received the lowest dose (1.5mg/kg OG). Rats that received OG treatment exhibited reduced serum CORT levels and CRH mRNA expression in the hypothalamus, suggesting that the hyperactivity of the HPA axis in CUMS rats was reversed by OG treatment. Moreover, OG treatment upregulated the protein levels of BDNF and phosphorylated-ERK1/2 in the hippocampus, even above control levels. Our findings suggest that OG improved depressive behaviour in CUMS rats by downregulating HPA axis hyperactivity and increasing BDNF expression and ERK1/2 phosphorylation in the hippocampus.

Interleukin-23 as a potential therapeutic target for rheumatoid arthritis

Cytokine-mediated immunity plays a crucial role in the pathogenesis of various autoimmune diseases, including rheumatoid arthritis (RA). Increasing evidence has revealed the importance of IL-23, which closely resembles IL-12 structurally and immunologically, in linking innate and adaptive immunity. IL-23, a newly identified heterodimeric pro-inflammatory cytokine, is composed of a p40 subunit in common with IL-12 and a unique p19 subunit. Recent evidence suggests that IL-23, rather than IL-12, is the crucial factor in the pathogenesis of various immune-mediated disorders. In addition, recent studies have explored the role of IL-23 in patients with RA. An elevated expression of IL-23 has been demonstrated in the synovial fibroblasts and plasma of patients with RA. Moreover, an association between IL-23 and IL-23R polymorphisms with susceptibility to RA has been reported. Therefore, the targeting of IL-23 or the IL-23 receptor has been proposed as a potential therapeutic approach for RA. In this review we will discuss the biological features of IL-23, and summarize recent advances in our understanding of the role of IL-23 in the pathogenesis and treatment of RA.

Protective effects of total flavonoids ofBidens bipinnataL. against carbon tetrachloride-induced liver fibrosis in rats

Bidens bipinnata L. is well known in China as a traditional Chinese medicine and has been used to treat hepatitis in clinics for many years. In a previous study we found that total flavonoids of Bidens bipinnata L. (TFB) had a protective effect against carbon tetrachloride (CCl4)‐induced acute liver injury in mice. Now this study was designed to investigate its therapeutic effect against CCl4‐induced liver fibrosis in rats and to determine, in part, its mechanism of action. The liver fibrosis model was established by subcutaneous injection of 50% CCl4 twice a week for 18 weeks. TFB (40, 80 and 160 mg kg−1) was administered by gastrogavage daily from the 9th week. The results showed that TFB (80 and 160 mg kg−1) treatment for 10 weeks significantly reduced the elevated liver index (liver weight/body weight) and spleen index (spleen weight/body weight), elevated levels of serum transaminases (alanine aminotransferase and aspartate aminotransferase), hyaluronic acid, type III procollagen and hepatic hydroxyproline. In addition, TFB markedly inhibited CCl4‐induced lipid peroxidation and enhanced the activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase. Moreover, TFB (80 and 160 mg kg−1) treatment improved the morphologic changes of hepatic fibrosis induced by CCl4 and suppressed nuclear factor (NF)‐kB, α‐smooth muscle actin (SMA) protein expression and transforming growth factor (TGF)‐β1 gene expression in the liver of liver fibrosis of rats. In conclusion, TFB was able to ameliorate liver injury and protect rats from CCl4‐induced liver fibrosis by suppressing oxidative stress. This process may be related to inhibiting the induction of NF‐kB on hepatic stellate cell activation and the expression of TGF‐β1.