HSP90 Exacerbates Bone Destruction in Rheumatoid Arthritis by Activating TRAF6/NFATc1 Signaling.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by a notably high disability rate, primarily attributed to cartilage and bone degradation. The involvement of heat shock protein 90 (HSP90) as a molecular chaperone in the inflammatory response of RA has been established, but its role in bone destruction remains uncertain. In the present study, the expression of HSP90 was augmented in osteoclasts induced by the receptor activator of nuclear factor-κB ligand. Additionaly, it was observed that the outcomes revealed a noteworthy inhibition of osteoclast formation and differentation when triptolide was utilized to hinder the expression of HSP90. Furthermore, the positive influence of HSP90 in osteoclast differentiation was substantiated by overexpressing HSP90 in osteoclast precursor cells. Mechanically, HSP90 significantly activated the TNF receptor-associated factor 6 (TRAF6)/Nuclear factor of activated T cells 1 (NFATc1) signaling axis, accompanied by markedly promoting osteoclast differentiation. This effect was consistently observed in the destructive joint of rats with collagen-induced arthritis, where HSP90 effectively activated osteoclasts and contributed to arthritic bone destruction by activating the TRAF6/NFATc1 signaling. Overall, the findings of this study provide compelling evidence that HSP90 exacerbates bone destruction in RA by promoting osteoclast differentiation through the activation of TRAF6/NFATc1 signaling, and interference with HSP90 may be a promising strategy for the discovery of anti-arthritic bone destruction agents.

[Effect of Tripterygium Glycosides Tablets on reproductive toxicity in male rats with â ¡ type collagen induced arthritis].

The aim of this paper was to observe the toxic effect of Tripterygium Glycosides Tablets on the reproductive system of Ⅱ type collagen induced arthritis(CIA) male rats, and to explore the toxic mechanism preliminarily. Fifty SD rats were randomly divided into normal control group(Con), model group(CIA), Tripterygium Glycosides Tablets clinical equivalent dose groups of 1, 2, 4 times(9, 18, 36 mg·kg~(-1)), 10 rats in each group, and were given by gavage once a day for 42 days after the first immunization. The organ index of testis and epididymis were calculated on days 21 and 42. Histopathological and morphological changes of testis and epididymis were observed under optical microscope. Sperm count, sperm malformation rate and sperm kinetic parameters in epididymal tissues were observed by computer assisted sperm analysis(CASA). The concentration of testosterone(T), nitric oxide synthase(NOS) and aromatase(CYP19 A1) in serum were detected by ELISA. Immunohistochemistry was used to observe the expression of Bax and Bcl-2 related proteins in the apoptosis pathway of testis and epididymis. The results showed that, compared with Con group, CIA group significantly increased the rate of testicular spermatogenic tubule lesion and sperm malformation, decreased the average path speed, and no significant changes were observed in other groups. Tripterygium Glycosides Tablets at 4 times clinical equivalent dose can significantly reduce the testis index(P<0.01), each dose group can reduce the epididymis index(P<0.05). Each dose group of Tripterygium Glycosides Tablets could cause different degrees of damage to the testis and epididymis, the proportion of testicular histopathology lesions increased, the number of spermatogenic cells in the seminiferous tubules decreased, and so on. It could reduce the number of sperm, increase the rate of sperm deformity, make the parameters of sperm dynamics abnormal, and so on. Tripterygium Glycosides Tablets at 4 times dose could significantly reduce the content of serum sex hormone T and key enzyme of androgen synthesis(P<0.05 or P<0.01), but had no effect on CYP19 A1. The expression of Bax and Bcl-2 in testis and epididymis were increased by 2 and 4 times doses of Tripterygium Glycosides Tablets(P<0.05, P<0.01 or P<0.01). The results showed that 21 d administration of Tripterygium Glycosides Tablets at equal or higher doses could induce obvious toxic effect to the reproductive organs of CIA male rats, and lower the level of serum sex hormone T and the key enzyme of androgen synthesis, NOS. The mechanism of abnormal changes of Bax and Bcl-2 in Testis and epididymis is still to be elucidated.

[Systematic reviews of effects of Tripterygium Glycosides Tablets on pro-inflammatory factors in rheumatoid arthritis].

To systematically evaluate the effects of Tripterygium Glycosides Tablets alone or in combination with methotrexate(MTX) and leflunomide(LEF) on the levels of pro-inflammatory cytokines in patients or animal models with rheumatoid arthritis(RA), and to provide reference for clinical application and related basic research, this study systematically searched databases of CNKI, VIP, WanFang, PubMed, Embase and Cochrane Library, collected relevant clinical or animal experimental studies, used risk assessment tools to evaluate the quality of research, and used Revman 5.3 software to conduct Meta-analysis or descriptive analysis of the outcome indicators included in the literatures. Of the 1 709 papers retrieved, 3 clinical studies and 12 animal experiments were included. The results showed that compared with MTX alone, Tripterygium Glycosides Tablets combined with MTX could further reduce the expression levels of peripheral blood TNF-α(SMD=-8.88,95%CI[-10.77,-6.99],P<0.000 01),IL-1ß(P<0.000 01) and IL-6(SMD=-8.63, 95%CI[-10.57,-6.69], P<0.000 01) in RA patients. Compared with LEF alone, the combination of Tripterygium Glycosides Tablets and LEF could not further reduce the expression levels of TNF-α(P=0.20), IL-1ß(P=0.17), IL-6(P=0.31). In RA animal model, compared with model group, Tripterygium Glycosides Tablets could reduce the expression levels of peripheral blood IL-1ß(SMD=-6.29,95%CI[-9.64,-2.93],P<0.000 2)in peripheral blood(SMD=-1.39,95%CI[-1.77,-1.02],P<0.000 01), joint fluid(P<0.000 01) and paw plasma(P=0.02), and also reduce the expression levels of TNF-α in RA animal model group. Compared with MTX alone, Tripterygium Glycosides Tablets alone reduced the same levels of TNF-α(P=0.42) and IL-6(P=0.08) in joint fluid, while Tripterygium Glycosides Tablets combined with MTX could further reduce the levels of IL-6(P=0.000 1) in joint fluid; compared with LEF alone, Tripterygium Glycosides Tablets have the similar effects on reducing the expression levels of peripheral blood TNF-α(P=0.16), IL-1ß(P=0.32), IL-6(P=0.12), while Tripterygium Glycosides Tablets combined with LEF could further reduce the expression levels of TNF-α(P=0.008), IL-1ß(P=0.02), IL-6(P<0.000 1) in peripheral blood. Therefore, Tripterygium Glycosides Tablets combined with MTX could further reduce the expression levels of pro-inflammatory cytokines in peripheral blood of RA patients. Tripterygium Glycosides Tablets alone could reduce the expression levels of pro-inflammatory cytokines in peripheral blood and local joint of RA animal models. Tripterygium Glycosides Tablets combined with MTX or LEF could further reduce the express levels of pro-inflammatory cytokines in peripheral blood of RA animal models. Due to the limitation of literature, this conclusion needs to be further validated.

[Meta-analysis of RCT studies on clinical efficacy of single administration of Tripterygium Glycosides Tablets or combined administration with methotrexate against rheumatoid arthritis].

To evaluate the clinical efficacy of single administration of Tripterygium Glycosides Tablets(TGT) or combined administration with methotrexate(MTX) against rheumatoid arthritis(RA) based on American College of Rheumatology(ACR) efficacy standard. Six databases, namely CNKI, WanFang, VIP, PubMed, Embase and Cochrane Library, were retrieved for randomized controlled trials(RCT), and clinical trials were screened out according to the preset inclusion and exclusion criteria. Then, the study quality was evaluated by the risk assessment tools. Data extraction and analysis were performed by using RevMan 5.3 software for Meta-analysis. Sensitivity analysis and publication bias analysis were made to test the stability and reliability of results. Until December 2018, a total of 1 709 articles were obtained, and finally 10 clinical RCT studies with a total of 1 184 patients were included. As a result, the single administration of TGT showed a significantly better ACR efficiency(RR=1.31, 95%CI[1.15, 1.49], P<0.000 1) than methotrexate(MTX). The combined administration of TGT and MTX showed a significantly better ACR efficiency(RR=1.28, 95%CI[1.20, 1.38], P<0.000 01) than the single administration of MTX. In conclusion, the single administration of TGT and the combined administration of TGT and MTX were more effective in achieving ACR20, ACR50, ACR70 compliance than the single administration of MTX. Further validations based on more RCT studies with high-quality are required.

[Overview of hepatotoxicity studies on Tripterygium wilfordii in recent 20 years].

Tripterygium wilfordii is widely used in the treatment of rheumatism with curative effect. However,its toxicity and adverse reactions,especially the hepatotoxicity,rank the first in the herbs induced liver injury,is the key factors hindering its clinical application. This paper reviewed the literatures related to the hepatotoxicity of T. wilfordii in recent 20 years,and summarized the characteristic of hepatotoxicity induced by T. wilfordii,the factors causing liver injury,the mechanism of toxicity,and the measures to reduce toxicity. In animal experiments,the T. wilfordii induced-hepatotoxicity in physiological state was more serious than pathological state. The T. wilfordii induced-hepatotoxicity is related to various toxic components contained in it,but alkaloids are the most toxic one.Overdose and cumulative overdose are the lead causing of hepatotoxicity induced by T. wilfordii. The theory of oxidative stress is still an important mechanism of T. wilfordii induced-hepatotoxicity,and Nrf2,as a key regulatory enzyme of oxidative stress,has become an important target for drugs to against T. wilfordii induced-hepatotoxicity. Mitochondrial autophagy and liver hypersensitivity are new mechanisms of liver injury induced by T. wilfordii. The measures such as dosage control,drug compatibility and dosage form variations can help to reduce the hepatotoxicity induced by T. wilfordii. This paper clarified the current situation and shortcomings of safety research on T. wilfordii,so as to propose new research strategies and provide ideas for rational evaluation of safety and clinical safe drug use of T. wilfordii.

[Effect of Tripterygium Glycosides Tablets on synovial angiogenesis in rats with type â ¡ collagen induced arthritis].

To observe the effect of Tripterygium Glycosides Tablets on angiogenesis of rats with type Ⅱ collagen-induced arthritis( CIA) and on the tube formation of human umbilical vein endothelial cells( HUVEC) in vitro. The HUVEC were induced by 20 µg·L-1 vascular endothelial growth factor( VEGF) in vitro,and were treated with 0. 1,1,10 mg·L-1 Tripterygium Glycosides Tablets continuously for 7 hours. The numbers of branches of tube formation were measured. SD rats were immunized to establish CIA. CIA rats were treated with 9,18,36 mg·kg-1·d-1 Tripterygium Glycosides Tablets for 42 days. Histopathological examination( HE) was performed to observe the vascular morphology and vascular density in the synovial membrane of the inflamed joints. Immunohistochemistry and immunofluorescence were performed to observe the expression of platelets-endothelial cell adhesion molecule( CD31) and αsmooth muscle actin( αSMA) in synovial membrane. Immunohistochemistry and Western blot were performed to observe the expression of hypoxia-inducible factors 1α( HIF1α) and angiotensin 1( Ang1) in the synovial tissue. The results showed that the numbers of branches of tube formation of HUVEC induced by VEGF were improved,and declined significantly after treated by Tripterygium Glycosides Tablets. Compared with the normal group,the vascular density,CD31 positive expression,CD31 +/αSMA-immature and total vascular positive expression in the synovial membrane of the model group were significantly increased,and so as HIF1α and Ang1 in the synovium. Tripterygium Glycosides Tablets reduced the synovial vascular density and inhibited the positive expression of CD31,CD31+/αSMA-immature blood vessels and total vascular,but has no effect on CD31+/αSMA+mature blood vessels. Tripterygium Glycosides Tablets also inhibited the expression of HIF1α and Ang1 in synovial membrane of inflammatory joints. Our results demonstrated that Tripterygium Glycosides Tablets could inhibit the angiogenesis of synovial tissue in CIA rats and the tube formation of HUVEC,which is related to the down-regulation of HIF1α/Ang1 signal axis.

[Effect of Tripterygium Glycosides Tablets on reproductive toxicity in female rats with â ¡ type collagen induced arthritis].

The aim of this paper was to observe the toxic effect of Tripterygium Glycosides Tablets( TG) on the reproductive system of Ⅱ type collagen induced arthritis( CIA) male rats,and to explore the toxic mechanism preliminarily. Fifty SD rats were randomly divided into normal control group( Con),model group( CIA),Tripterygium Glycosides Tablets clinical equivalent dose groups of 1,2,4 times( 9,18,36 mg·kg-1),10 rats in each group,and were given by gavage once a day for 42 days after the first immunization.The organ indexes of uterine and ovarian were calculated on days 21 and 42. Histopathological and morphological changes of uterine and ovarian were observed under optical microscope. The concentration of estradiol( E2),follicle-stimulating hormone( FSH),luteinizing hormone( LH),17α-hydroxylase( CYP17 A1) and cytochrome P450 19 A1( CYP19 A1) in serum were detected by ELISA. Immunohistochemistry was used to observe the expression of Bax and Bcl-2 related proteins in the apoptosis pathway of uterus and ovary. The results showed that compared with the Con group,CIA group could reduce the number of uterine glands( P<0.05),but no significant changes were observed in other groups. Compared with the CIA group,there were no significant changes in the coefficients of uterus and ovary in the Tripterygium Glycosides Tablets groups. The number of uterine glands,total follicles in the ovary,mature follicles and corpus luteum,the distribution of blood vessels and mitochondria had a certain inhibitory trend,and also slightly increased the number of atresia follicles,but the histopathological quantitative indicators were not statistically different. Except that 2 times clinical dose of Tripterygium Glycosides Tablets could significantly reduce the content of CYP19 A1( P<0. 05) after 42 d administration,there were no significant changes in serum estrogen E2,FSH,LH and estrogen synthesis key enzymes CYP17 A1 in each administration group. Medium and high doses of Tripterygium Glycosides Tablets could increase the expression of apoptotic protein Bax in uterine and ovarian tissues( P<0. 05,P<0. 01),and all the administration groups could inhibit the expression of apoptotic inhibiting protein Bcl-2( P <0. 05,P<0. 01,P<0.001),42 d was more obvious than 21 d. In conclusion,4 times and less than 4 times Tripterygium Glycosides Tablets did not cause obvious toxicity and histopathological changes in the reproductive organs of CIA rats,but it could reduce the level of serum estrogen synthesis key enzyme CYP19 A1 and affect the content of apoptosis-related proteins Bax and Bcl-2 in uterus and ovary tissues. The relevant mechanism needs further study.

[Comparative study on dose-toxicity-effect of Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets on CIA model rats].

The aim of this paper was to compare the properties of Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets from dose-effect-toxicity on type Ⅱ collagen-induced arthritis( CIA) in rats. SD rats were randomly divided into eight groups,including normal group,model group,Tripterygium Glycosides Tablets groups( 1 times equivalent dose 0.009 g·kg-1,4 times equivalent dose 0.036 g·kg-1,16 times equivalent dose 0.144 g·kg-1),Tripterygium wilfordii Tablets groups( 1 times equivalent dose 0.007 5 mg·kg-1,4 times equivalent dose 0.030 mg·kg-1,16 times equivalent dose 0.120 mg·kg-1). Beginning on the first immunization,Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets administered intraperitoneally once a day. After the second immunization,the symptoms such as redness and swelling of joints were observed,and the clinical score and incidence of arthritis were evaluated. HE and Masson staining were used to examine the histopathological changes of joints. The expression level of anti-type Ⅱ collagen antibody Ig G in serum was detected by ELISA,routine testing of blood components,the concentration of ALP( alkaline phosphatase),ALT( alanine aminotransferase),AST( aspartate aminotransferase),GGT( gamma-glutamyltransferase),TBi L( total bilirubin),CRE( creatinine) and UREA( urea) in serum were detected by enzymatic assay. The rate of sperm deformity in the epididymis was evaluated under light microscope. The extent of damage to the testis and ovarian tissue was assessed by HE staining. Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets attenuated the inflammation,redness,swelling and deformity of joints and reduced the clinical score and incidence of arthritis in CIA rats. Meanwhile,it also exhibited obvious reduction in all pathological features such as joint synovitis,pannus,cartilage erosion and bone destruction. Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets reduced Ig G in a dose-dependent manner,and Tripterygium Glycosides Tablets is better than Tripterygium wilfordii Tablets( P<0.05 or P<0.01). The high doses of Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets could significantly increase the organ coefficient of liver and spleen and reduced RBC and HGB in CIA rats( P<0.01),and severity leading to death. Gastric mucosal injury and morphological changes of liver and kidney were not observed in CIA rats of Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets treatment group. The 4 and 16 times doses of Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets could significantly increase serum ALT,GGT and decrease CRE( P<0.05 or P<0.01). Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets could increase the sperm deformity rate and damage the testicular seminiferous tubules of CIA male rats. Severity increased with dose and time increasing. The effect of Tripterygium Glycosides Tablets( 16 times) is more significant than Tripterygium wilfordii Tablets( 16 times). Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets significantly delayed onset of arthritis and inhibited the paw edema and arthritic score. Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets also caused male reproductive damage,high dose affected hematopoiesis,and maximum dose leading to death. Tripterygium Glycosides Tablets and Tripterygium wilfordii Tablets all depended on dose-effect-toxicity manner. Anti-arthritis effect of Tripterygium Glycosides Tablets is better than Tripterygium wilfordii Tablets,but the toxicity of Tripterygium Glycosides Tablets maximum dose is more obvious. The relevant conclusions of our study will provide experimental references for clinical rational use of drugs,and further clinical studies are needed to confirm our conclusions.

[Meta-analysis of laboratory index of Tripterygium Glycosides Tablets in treatment of rheumatoid arthritis].

The aim of this study was to systematically evaluate the clinical efficacy of Tripterysium Glycosides Tablets( TGT) alone or in combination with methotrexate( MTX) in the treatment of rheumatoid arthritis( RA) based on the laboratory index criteria and to provide a basis for the clinical application of TGT against RA. Six databases including CNKI,Wan Fang,VIP,PubMed,EMbase and Cochrane were retrieved for randomized controlled trials( RCT) about TGT alone or combination with MTX in the treatment of RA.Then risk assessment tools were used for quality evaluation of the studies,and data extraction and analysis were conducted by using Rev Man 5.3 software for Meta-analysis. A total of 1 709 articles were retrieved,and finally 25 studies were included,with a total sample size of 2 507 cases. Meta-analysis results showed that between TGT alone and TGT alone,MDESR=-2. 66,95%CI[-8.17,2.86],P = 0.35; MDCRP=-2.38,95%CI[-9.01,4.24],P = 0.48; between TGT combined with MTX and MTX alone,MDESR= 8.74,95%CI[6.72,10.76],P<0.000 01; MDCRP= 5.37,95%CI[3.71,7.03],P<0.000 01; SMDRF= 1.05,95%CI[0.51,1.60],P = 0.000 1.The effect of TGT on decreasing CRP and ESR in RA patients was similar to the MTX. In addition,TGT combined with MTX were more effective in decreasing CRP,ESR,RF than MTX alone. However,due to the potential bias in the included studies,more and high-quality randomized controlled trials would be needed to improve the level of evidence.

[Clinical symptoms effect of Tripterygium Glycosides Tablets alone or combined with methotrexate in treatment of rheumatoid arthritis: a Meta-analysis].

To systematically review the improvement effects of Tripterygium Glycosides Tables( TGT) alone or in combination with methotrexate( MTX) on the clinical signs and symptoms of rheumatoid arthritis( RA),and provide a basis for the rational use of TGT in clinic,in the current study,six literature databases including CNKI,Wan Fang,VIP,PubMed,EMbase,and Cochrane Library,were systematically searched,according to the inclusion and exclusion criteria. Review Manager 5.3 software was used to input the literatures,and we assessed the risk bias on the level of outcome indicators for each included literature. A total of 18 literatures were included,and the classification results showed that: compared with MTX,TGT alone can reduce the number of joint swelling( MD =0. 18,95%CI[-1.06,1.42],P = 0.78) and joint tenderness( MD =-0.06,95% CI[-1.69,1.56],P = 0.94) in RA patients with the same effect as MTX. In terms of drug combination,TGT combined with MTX had an advantage over MTX alone in lessening the morning stiffness time( MD = 18. 24,95% CI[12. 64,23. 84],P < 0. 000 01) of RA,joint tenderness( MD = 2. 65,95% CI[1. 85,3. 44],P<0.000 01) and joint swelling( MD = 3.01,95% CI[2.09,3.39],P< 0.000 01). In conclusion,this Meta-analysis suggest that TGT alone was superior to MTX in improving joint swelling and tenderness in RA patients,TGT combined with MTX may improve the clinical manifestation of RA patients better than MTX alone.

Protective Mechanism of the Antioxidant Baicalein toward Hydroxyl Radical-Treated Bone Marrow-Derived Mesenchymal Stem Cells.

Our study explores the antioxidant and cytoprotective effects of baicalein and further discusses the possible mechanisms. A methyl thiazolyl tetrazolium (MTT) assay revealed that baicalein could considerably enhance the viability of hydroxyl radical-treated bone marrow-mesenchymal stem cells (bmMSCs) at 37-370 µM. The highest viability rate was 120.4%. In subsequent studies, baicalein was observed to effectively scavenge hydroxyl radical and PTIO• radicals, reducing Fe3+ and Cu2+ ions. In the Fe2+-chelating UV-vis spectra, mixing of baicalein with Fe2+ yielded two evident redshifts (275 → 279 nm and 324 → 352 nm) and a broad absorption peak (λmax ≈ 650 nm, ε = 1.6 × 10³ L mol-1·cm-1). Finally, we compared the Fe2+-chelating UV-vis spectra of baicalein and its analogues, including 5-hydroxyflavone, 6-hydroxyflavone, 7-hydroxyflavone, catechol, pyrogallol, and chrysin. This analysis revealed that the 4-keto group of the C-ring played a role. The 5,6,7-trihydroxy-group (pyrogallol group) in the A-ring served as an auxochrome, enhancing the absorbance of the UV-vis spectra and deepening the color of the Fe2+-complex. We concluded that baicalein, as an effective hydroxyl radical-scavenger, can protect bmMSCs from hydroxyl radical-mediated oxidative stress. Its hydroxyl radical-scavenging effects are likely exerted via two pathways: direct scavenging of hydroxyl radicals, possibly through electron transfer, and indirect inhibition of hydroxyl radical generation via Fe2+ chelation through the 4-keto-5,6,7-trihydroxy groups.

MicroRNA-125a-3p is involved in early behavioral disorders in stroke-afflicted rats through the regulation of Cadm2.

Ischemic strokes carry a significant risk of mortality and recurrent vascular events. Recent studies suggest that changes in microRNAs (miRNAs or miRs) may affect the development of the stroke. However, few studies have investigated the role of miRNAs in behavioral disorder in early stroke. In the present study, animal models of middle cerebral artery occlusion (MCAO) are used, as well as a cell model of neurite outgrowth to further investigate the role of miRNAs in targeting synapse-associated proteins expression in early stroke. The authors used miRNA expression microarrays on RNA extracted from the cortex tissue samples from the rats of MCAO and control rats. Reverse transcription­quantitative polymerase chain reaction was conducted to verify the candidate miRNAs discovered by microarray analysis. Data indicated that miR­125a was significantly increased in the cortex of the model of MCAO, which were concomitant with that rats of MCAO at the same age displayed significant behavioral deficits. Bioinformatics analysis predicted the cell adhesion molecule 2 (Cadm2, mRNA) neurite outgrowth-associated protein is targeted by miR­125a. Overexpression of miR­125a reduced the level of Cadm2 expression in PC12 cell injury induced by free-serum. In contrast, inhibition of miR­125a using miR­125a inhibitors significantly resulted in higher levels of Cadm2 expression. In conclusion, miR­125a is involved in the behavioral disorder of animal models of MCAO by regulation of Cadm2.

Role of the p-Coumaroyl Moiety in the Antioxidant and Cytoprotective Effects of Flavonoid Glycosides: Comparison of Astragalin and Tiliroside.

The aim of this study was to explore the role of p-coumaroyl in the antioxidant and cytoprotective effects of flavonoid glycosides. The antioxidant effects of astragalin and tiliroside were compared using ferric ion reducing antioxidant power, DPPH• scavenging, ABTS•⁺ scavenging, •O2- scavenging, and Fe2+-chelating assays. The results of these assays revealed that astragalin and tiliroside both exhibited dose-dependent activities; however, tiliroside exhibited lower IC50 values than astragalin. In the Fe2+-chelating assay, tiliroside gave a larger shoulder-peak at 510 nm than astragalin, and was also found to be darker in color. Both of these compounds were subsequently evaluated in a Fenton-induced mesenchymal stem cell (MSC) damaged assay, where tiliroside performed more effectively as a cytoprotective agent than astragalin. Tiliroside bearing a 6''-O-p-coumaroyl moiety exhibits higher antioxidant and cytoprotective effects than astragalin. The 6''-O-p-coumaroyl moiety of tiliroside not only enhances the possibility of electron-transfer and hydrogen-atom-transfer-based multi-pathways, but also enhances the likelihood of Fe-chelating. The p-coumaroylation of the 6"-OH position could therefore be regarded as a potential approach for improving the antioxidant and cytoprotective effects of flavonoid glycosides in MSC implantation therapy.

Lyophilized aqueous extracts of Mori Fructus and Mori Ramulus protect Mesenchymal stem cells from •OH-treated damage: bioassay and antioxidant mechanism.

BACKGROUND: Mori Fructus and Mori Ramulus are two traditional Chinese herbal medicines from mulberries. The present work explores their beneficial effects on •OH-treated mesenchymal stem cells (MSCs) and discusses possible mechanisms. METHODS: Lyophilized aqueous extracts of Mori Fructus (LAMF) and Mori Ramulus (LAMR) were prepared and analyzed using HPLC. LAMF and LAMR (along with morin) were further investigated for their effects on •OH-treated MSCs using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. The direct antioxidation mechanisms were studied using 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO•)-scavenging, 2,2'-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS+•)-scavenging and 1,1-diphenyl-2-picryl-hydrazl (DPPH•)-scavenging, as well as Cu2+-reducing and Fe3+-reducing antioxidant power. Finally, the indirect antioxidant mechanism was investigated based on the UV-vis spectra of Fe2+-chelation. RESULTS: In each LAMF and LAMR, seven phytophenols were successfully measured by HPLC, including five flavonoids (morin, rutin, astragalin, isoquercitrin and luteolin) and two non-flavonoids (chlorogenic acid and maclurin). MTT assays revealed that LAMF, LAMR and morin could effectively increase the survival of •OH-treated MSCs at 10-100 µg/mL, and could effectively scavenge PTIO• (IC 50 6609.7 ± 756.6, 4286.9 ± 84.9 and 103.4 ± 0.9 µg/mL, respectively), DPPH• (IC 50 208.7 ± 3.0, 97.3 ± 3.1 and 8.2 ± 0.7 µg/mL, respectively) and ABTS+• (IC 50 73.5 ± 5.8, 34.4 ± 0.1 and 4.2 ± 0.2 µg/mL, respectively), and reduce Cu2+ (IC 50 212.5 ± 7.0, 123.2 ± 0.9 and 14.1 ± 0.04 µg/mL, respectively) & Fe3+ (IC 50 277.0 ± 3.1, 191.9 ± 5.2 and 5.0 ± 0.2 µg/mL, respectively). In the Fe2+-chelating assay, the five flavonoids produced much stronger shoulder-peaks than the two non-flavonoids within 420-850 nm. CONCLUSION: Mori Fructus and Mori Ramulus, can protect MSCs from •OH-induced damage. Such beneficial effects can mainly be attributed to the antioxidant action of phytophenols, which occurs via direct (ROS-scavenging) and indirect mechanism (Fe2+-chelating). The ROS-scavenging mechanism, however, include at least a H+-transfer and an electron-transfer (ET), and possibly includes a hydrogen-atom-transfer (HAT). In the Fe2+-chelating, flavonoids are more effective than non-flavonoids. This can be attributed to several adjacent planar chelating-sites between the 3-OH and 4-C = O, between the 4-C = O and 5-OH, or between the 3'-OH and 4'-OH in flavonoids. Such multiple-Fe2+-chelating reactions cause overlap in the UV-vis absorptions to deepen the complex color, enhance the peak strength, and form shoulder-peaks. By comparison, two non-flavonoids with catechol moiety produce only a weak single peak.