Estrogen and testosterone attenuate extracellular matrix loss in collagen-induced arthritis in rats

Correlation between low testosterone levels and the risk of osteoarthritis: a cross-sectional analysis of NHANES data (2011-2016)

BACKGROUND

Osteoarthritis (OA) is a common degenerative joint disease that significantly impacts the quality of life, especially among older adults. Testosterone, a critical hormone for musculoskeletal health, has been suggested to influence OA pathogenesis. However, the relationship between low testosterone levels and OA risk remains underexplored in large, representative populations. This study aimed to investigate the association between low testosterone levels and OA risk using data from the National Health and Nutrition Examination Survey (NHANES, 2011-2016).

METHODS

This cross-sectional analysis included 4,548 participants from NHANES, a nationally representative U.S.

DATASET

Testosterone levels were categorized as low or normal, with low testosterone defined as < 300 ng/dL for men and population-based cutoffs for women. The presence of OA was determined through self-reported physician diagnosis. Multivariable logistic regression models were used to examine the association between testosterone levels and OA risk, adjusting for demographic, socioeconomic, lifestyle, and clinical factors. Restricted cubic spline (RCS) analysis was conducted to evaluate non-linear relationships. Subgroup analyses were performed to assess consistency across key demographic and clinical strata.

RESULTS

Among the 4,548 participants, 812 (17.9%) were diagnosed with OA. Participants with OA were older, more likely to be female, and exhibited higher rates of obesity and hyperlipidemia. In fully adjusted models, low testosterone levels were significantly associated with increased OA risk (OR, 1.22; 95% CI, 1.02-1.46; P = 0.028). RCS analysis indicated a non-linear relationship, with a steep increase in OA risk at lower testosterone levels, suggesting a threshold effect. Subgroup analyses demonstrated consistent associations across demographic and clinical groups without significant interactions.

CONCLUSION

Low testosterone levels are independently associated with an increased risk of OA in the U.S.

POPULATION

These findings underscore the potential role of hormonal health in OA pathogenesis and highlight the need for longitudinal studies to clarify causal pathways. The observed non-linear relationship suggests that maintaining optimal testosterone levels may be important for joint health, and testosterone replacement therapy could be explored as a preventative strategy for individuals with testosterone deficiency.

Transmenopausal changes in cortical bone quality

Bone's resistance to fracture depends on its amount and quality, the latter including its structural and material/compositional properties. Bone material properties are dependent on bone turnover rates, which are significantly elevated immediately following menopause. Previously published data reported that following menopause, the amount of organic matrix synthesized at actively forming surfaces is significantly decreased, while glycosaminoglycan content was also modulated at resorbing surfaces, in the cancellous compartment. In the present study, we used Raman microspectroscopic analysis of paired iliac crest biopsies obtained before and shortly after menopause (1 year after cessation of menses) in healthy females to investigate changes in material/compositional properties due to menopause, in the cortical compartment. Specifically, the mineral/matrix ratio, the relative proteoglycan content, the mineral maturity/crystallinity, and the relative pyridinoline collagen cross-link content were determined at actively forming intracortical surfaces (osteons) as a function of tissue age, as well as in interstitial bone. Results indicated that it is the freshly synthesized organic matrix content that significantly declines following menopause, in agreement with what was previously reported for the cancellous compartment. This decline was not evident in the freshly deposited mineral content. None of the compositional/quality properties were altered following menopause either. Finally, no differences in any of the monitored parameters were evident in cortical interstitial bone.

Sex-dependent variation in cartilage adaptation: from degeneration to regeneration

Despite acknowledgement in the scientific community of sex-based differences in cartilage biology, the implications for study design remain unclear, with many studies continuing to arbitrarily assign demographics. Clinically, it has been well-established that males and females differ in cartilage degeneration, and accumulating evidence points to the importance of sex differences in the field of cartilage repair. However, a comprehensive review of the mechanisms behind this trend and the influence of sex on cartilage regeneration has not yet been presented. This paper aims to summarize current findings regarding sex-dependent variation in knee anatomy, sex hormones' effect on cartilage, and cartilaginous degeneration and regeneration, with a focus on stem cell therapies. Findings suggest that the stem cells themselves, as well as their surrounding microenvironment, contribute to sex-based differences. Accordingly, this paper underscores the contribution of both stem cell donor and recipient sex to sex-related differences in treatment efficacy. Cartilage regeneration is a field that needs more research to optimize strategies for better clinical results; taking sex into account could be a big factor in developing more effective and personalized treatments. The compilation of this information emphasizes the importance of investing further research in sex differences in cartilage biology.

Sex bias in lymphocytes: Implications for autoimmune diseases

Autoimmune diseases are characterized by a significant sex dimorphism, with women showing increased susceptibility to disease. This is, at least in part, due to sex-dependent differences in the immune system that are influenced by the complex interplay between sex hormones and sex chromosomes, with contribution from sociological factors, diet and gut microbiota. Sex differences are evident in the number and function of lymphocyte populations. Women mount a stronger pro-inflammatory response than males, with increased lymphocyte proliferation, activation and pro-inflammatory cytokine production, whereas men display expanded regulatory cell subsets. Ageing alters the immune landscape of men and women in differing ways, resulting in changes in autoimmune disease susceptibility. Here we review the current literature on sex differences in lymphocyte function, the factors that influence this, and the implications for autoimmune disease. We propose that improved understanding of sex bias in lymphocyte function can provide sex-specific tailoring of treatment strategies for better management of autoimmune diseases.

Omega 3 polyunsaturated fatty acids: Potential anti-inflammatory effect in a model of ovariectomy and temporomandibular joint arthritis induction in rats

OBJECTIVE

To evaluate the effect of polyunsaturated fatty acid-type omega 3 (ω3) on the temporomandibular joint (TMJ) of ovariectomized rats (OVX) with rheumatoid arthritis (RA).

DESIGN

Rheumatoid arthritis was induced using complete Freund's adjuvant and type II bovine collagen injected at the base of the tail. Twenty-four adult female rats were treated by gavage and divided into four groups: G1: Sham, treated with 0.9% NaCl; G2: OVX, treated with 0.9% NaCl; G3: OVX+RA treated with 0.9% NaCl; G4: OVX+RA+ω3 treated with omega 3 (300 mg/kg/day). The induction of rheumatoid arthritis in groups G3 and G4 was performed 21 days after OVX, treatments were started 15 days after the induction of rheumatoid arthritis, maintained for 7 days, and killed. Bilateral TMJs were removed and assigned to morphometric analysis by micro-computed tomography and immunoassay to assess levels of cytokines IL-1β, IL-6, TNF-α, and IL-10.

RESULTS

Higher levels of inflammatory cytokines were found in the G2 and G3 (P < 0.05) and anti-inflammatory cytokines in the G1 and G4. TMJ analysis by micro-computed tomography showed a higher percentage of bone volume (median - interquartile deviation) in G1 (96.2-1.1) than in the G2 (91.5-2.0, P = 0.0374) and G3 (85.1-5.2, P = 0.0001) but showed no statistically significant differences with the G4 (93.1-1.7, P = 0.79).

CONCLUSIONS

Omega 3 successfully reduced TMJ damage in rats caused by ovariectomy and induced rheumatoid arthritis, and is a promising alternative for bone repair and attenuation of inflammatory processes.

The positive effect of pregnancy in rheumatoid arthritis and the use of medications for the management of rheumatoid arthritis during pregnancy

Rheumatoid arthritis (RA) is an autoimmune systemic inflammatory disorder that is mostly characterised by progressive symmetrical joint destruction, particularly in the wrist and fingers, while it may also affect additional joints and several organs, such as the skin, heart, blood vessels, and lungs. It is identified by raised anti-rheumatoid factor and anti-cyclic citrullinated peptide antibodies. The chemical mediators involved in the activity of RA are IL-1β, TNF-α, and IL-6. Pregnancy exerts a positive effect on RA that helps to modulate the disease condition. Different hypotheses are recommended to explain the ameliorating effect of pregnancy in RA. RA cannot be completely cured. The treatment goal is the attrition of pain and inflammation and the further progression of the disease. Long-term management of RA is carried out using disease-modifying antirheumatic drugs (DMARDs). Therapy of acute flares can be done with Non-steroidal anti-inflammatory drugs (NSAIDs) accompanied by ad interim usage of glucocorticoids. Biologic response modifiers are also available; they act by abolishing the activity of T- cells. However, it is necessary to select the correct treatment regimen when it comes to the management of RA in pregnancy.

Effect of glucosamine sulphate on the temporomandibular joint of ovariectomised rats

Glycosamine is an amino-monosaccharide present in connective and cartilage tissues that contribute to the maintenance, resistance, flexibility, and elasticity of these tissues. This study aimed to determine the in vivo effects of glucosamine sulphate (GS) on the temporomandibular joint (TMJ) of ovariectomised rats (OVX).Thirty-two rats were distributed into four groups as follows: G1, sham-OVX+saline solution; G2, sham-OVX+glucosamine sulphate (80mg/kg) - oral administration; G3, OVX+saline solution; G4, OVX+glucosamine sulphate (80mg/kg) - oral administration. Animals were treated for seven days. The TMJ was removed and stained with toluidine blue. The thickness of the cartilage layers and cytokines IL-1β, IL-6, and TNF-α levels were determined by histomorphometry and immunoassay, respectively. The administration of GS to OVX females did not change the thickness of condylar cartilage when compared with the other groups (p>0.05). There was an increase in the total cartilage thickness in sham-OVX females. IL-1β and TNF-α levels were significantly lower in sham-OVX females than in OVX females, indicating that ovariectomy acts as potent cytokine inducer. IL-6 levels were significantly higher in sham-OVX females. GS did not affect cytokine production in OVX females (p>0.05). In conclusion, the administration of GS did not affect cytokine levels, but did induce an increase in the total thickness of the TMJ condylar cartilage in sham-OVX rats.

Environmental Basis of Autoimmunity

The three common themes that underlie the induction and perpetuation of autoimmunity are genetic predisposition, environmental factors, and immune regulation. Environmental factors have gained much attention for their role in triggering autoimmunity, with increasing evidence of their influence as demonstrated by epidemiological studies, laboratory research, and animal studies. Environmental factors known to trigger and perpetuate autoimmunity include infections, gut microbiota, as well as physical and environmental agents. To address these issues, we will review major potential mechanisms that underlie autoimmunity including molecular mimicry, epitope spreading, bystander activation, polyclonal activation of B and T cells, infections, and autoinflammatory activation of innate immunity. The association of the gut microbiota on autoimmunity will be particularly highlighted by their interaction with pharmaceutical agents that may lead to organ-specific autoimmunity. Nonetheless, and we will emphasize this point, the precise mechanism of environmental influence on disease pathogenesis remains elusive.

Estrogens do not protect, but androgens exacerbate, collagen accumulation in the female mouse kidney after ureteric obstruction

AIMS

Controversy surrounds the gender basis of progression in chronic kidney disease. Unfortunately, most experimental studies addressing this question do not distinguish between direct effects of estrogen and indirect activation of estrogen receptors through conversion of testosterone to 17β-estradiol by aromatase. We examined the pathogenesis of renal fibrosis in female aromatase knockout (ArKO) mice, which lack circulating and stored estrogens, while having normal levels of testosterone.

MAIN METHODS

ArKO mice and their wild-type (ArWT) counterparts were subjected to unilateral ureteric obstruction (UUO), with kidney tissue collected at day(D) 0, 3 and 9 post-UUO. Effects of 5α-dihydrotestosterone (DHT) administration on each genotype were also studied. Tissue was assessed biochemically and histochemically for fibrosis. Western blot analysis was used to measure α-smooth muscle actin (α-SMA) expression and TGF-β1 signalling. Matrix metalloproteinase-2 (MMP-2) activity was measured by zymography.

KEY FINDINGS

UUO increased collagen content over time (p<0.05 (D3) and p<0.01 (D9) vs day 0), with no difference between genotypes in qualitative (collagen IV staining) and quantitative (hydroxyproline concentration) analyses. Systemic administration of non-aromatizable DHT increased collagen content after 3days of UUO in both genotypes. This was not paralleled by any change in α-SMA (myofibroblast burden) or TGF-β1 signalling but was commensurate with DHT reducing MMP2 activity in both genotypes (p<0.05 vs genotype controls).

SIGNIFICANCE

Physiological concentrations of estrogens do not protect the injured kidney from fibrosis progression. Androgens rather than estrogens are the relevant factor involved in regulating disease-related renal scarring in this model.

Investigation of the effects of estrogen on skeletal gene expression during zebrafish larval head development

The development of craniofacial skeletal structures requires well-orchestrated tissue interactions controlled by distinct molecular signals. Disruptions in normal function of these molecular signals have been associated with a wide range of craniofacial malformations. A pathway mediated by estrogens is one of those molecular signals that plays role in formation of bone and cartilage including craniofacial skeletogenesis. Studies in zebrafish have shown that while higher concentrations of 17-β estradiol (E 2) cause severe craniofacial defects, treatment with lower concentrations result in subtle changes in head morphology characterized with shorter snouts and flatter faces. The molecular basis for these morphological changes, particularly the subtle skeletal effects mediated by lower E 2 concentrations, remains unexplored. In the present study we address these effects at a molecular level by quantitative expression analysis of sets of candidate genes in developing heads of zebrafish larvae treated with two different E 2 concentrations. To this end, we first validated three suitable reference genes, ppia2, rpl8 and tbp, to permit sensitive quantitative real-time PCR analysis. Next, we profiled the expression of 28 skeletogenesis-associated genes that potentially respond to estrogen signals and play role in craniofacial development. We found E 2 mediated differential expression of genes involved in extracellular matrix (ECM) remodelling, mmp2/9/13, sparc and timp2a, as well as components of skeletogenic pathways, bmp2a, erf, ptch1/2, rankl, rarab and sfrp1a. Furthermore, we identified a co-expressed network of genes, including cpn1, dnajc3, esr1, lman1, rrbp1a, ssr1 and tram1 with a stronger inductive response to a lower dose of E 2 during larval head development.

Dependence of cytokine levels on the sex of experimental animals: a pilot study on the effect of oestrogen in the temporomandibular joint synovial tissues

The aim of this study was to evaluate the effects of 17β-oestradiol (E2) on cartilage thickness and cytokine levels in the temporomandibular joint (TMJ). Thirty rats (15 female, 15 male) were orchidectomized (ORX), ovariectomized (OVX), or sham-operated. After 21 days, animals were assigned to six groups: (1) sham-ORX; (2) ORX; (3) ORX+E2; (4) sham-OVX; (5) OVX; and (6) OVX+E2. Treatments were administered daily for 21 days. The thickness of cartilage layers (fibrous, proliferative, maturation, and hypertrophic) and cytokine levels (interleukins IL-1α, IL-1β, IL-6, and tumour necrosis factor alpha (TNF-α)) were measured by histomorphometry and ELISA, respectively. Kruskal-Wallis/Dunn's tests were used (alpha=5%). Sham-ORX showed thicker layers than ORX+E2, but not thicker than ORX. All layers, except the hypertrophic layer, were thicker in sham-OVX than OVX or OVX+E2. Although IL-1β levels were higher in castrated animals, E2 did not affect the level of this cytokine. IL-1α levels were higher in both ORX (P=0.0010) and ORX+E2 (P=0.0053) than in sham-ORX. However, E2 decreased IL-1α levels in OVX (P=0.0129). When compared to sham-ORX/OVX, IL-6 levels were not affected by E2 in males but were reduced in OVX (P=0.0079) and increased in OVX+E2 (P=0.0434). Levels of TNF-α were reduced by E2 in both ORX+E2 and OVX+E2. E2 treatment caused gender- and layer-dependent changes in the cartilage. Castration increased all cytokine levels, except for IL-6, without respect to gender.

Influence of racing on the serum concentrations of acute-phase proteins and bone metabolism biomarkers in racing greyhounds

This study was designed to evaluate the influence of racing on the serum concentrations of the acute-phase proteins (APPs) C-reactive protein (CRP), haptoglobin (Hp) and serum amyloid A (SAA) in 32 endurance-racing greyhounds. The study also aimed to investigate the effect of a 7 km race on the bone biomarkers osteocalcin (OC), bone-specific alkaline phosphatase (b-ALP) and pyridinoline cross-links (PYD). Total white blood cell (WBC) count, and the serum concentrations of cortisol, tumour necrosis factor-α (TNF-α), vitamin D and testosterone were also determined. Blood samples were collected 24 h prior to (T0) and within 2 h of completion of the race (T1). Compared to baseline values, WBC count did not change significantly (P = 0.2300), serum cortisol, Hp and SAA increased, while TNF-α and CRP decreased (P <0.0001 for each). There were no significant differences between the pre- and post-race serum concentrations of OC and PYD (P = 0.9500 and P = 0.2600, respectively), but serum b-ALP increased significantly (P = 0.0004). Serum concentrations of vitamin D and testosterone increased after racing (P = 0.0100 and P <0.0001, respectively). In this study, a 7 km race stimulated an acute-phase response, demonstrated by significant increases in the serum concentrations Hp and SAA in racing greyhounds. Increased serum b-ALP post-race probably indicates a change in bone metabolism and deserves further study.

Transmenopausal changes in trabecular bone quality

Bone strength depends on its amount and quality. Bone quality includes its structural and material properties. Bone material properties are dependent on bone turnover rates. Remodeling rates are significantly increased immediately after menopause. In the present study, we used Raman microspectroscopic analysis of double iliac crest biopsies with a spatial resolution of 1 µm obtained before and immediately after menopause (1 year after cessation of menses) in healthy females to investigate changes in material properties attributable to menopause. In particular, the mineral/matrix ratio, the relative proteoglycan and lipid content, the mineral maturity/crystallinity, and the relative pyridinoline collagen cross-link content were determined in trabecular bone as a function of surface metabolic activity and tissue age. The results indicate that significant changes (specifically in mineral/matrix ratio) were evident at active bone forming surfaces, whereas the relative proteoglycan content was altered at resorbing surfaces. These changes were not accompanied by altered mineral content or quality as monitored by Raman microspectroscopic analysis.

Estrogen reduces mechanical injury-related cell death and proteoglycan degradation in mature articular cartilage independent of the presence of the superficial zone tissue

OBJECTIVE

To study the effect of 17β-estradiol (E2) and the superficial zone (SFZ) on cell death and proteoglycan degradation in articular cartilage after a single injurious compression in vitro.

METHOD

Cartilage explants from the femoropatellar groove of 2 year old cows with or without the SFZ were cultured serum-free with physiological concentrations of E2 and injured by an unconfined single load compression (strain 50%, velocity 2 mm/s). After 96 h cell death was measured histomorphometrically (nuclear blebbing (NB) and TUNEL staining) and release of glycosaminoglycans (GAG) by DMMB assay.

RESULTS

Injurious compression increased significantly the number of cells with NB and TUNEL staining and release of GAG. Physiological concentrations of E2 prevented the injury-related cell death and reduced the GAG release significantly in a receptor-mediated manner (shown by co-stimulation with the antiestrogen fulvestrant/faslodex/ICI-182,780). The presence of the SFZ did not alter the NB response to either the mechanical injury or E2, but reduced the overall release of GAG significantly.

CONCLUSION

E2 prevents injury-related cell death and GAG release, and might be useful for the development of treatment options for either cartilage-related sports injuries or osteoarthritis (OA). The SFZ does not seem to play an important role in (1) the E2-related tissue response and (2) the mechanically-induced cell death in deeper regions of the explants and GAG release. The latter might be related to the unconfined nature of the injury model.

Mesenchymal stromal cells versus betamethasone can dampen disease activity in the collagen arthritis mouse model

The objective of this study was to compare between the effects of mesenchymal stem cell (MSC) and betamethasone in the treatment of rheumatoid arthritis. Sixty male albino mice were divided equally into 2 models. They are MSC model, group 1: saline control group, group 2: collagen-induced arthritis (CIA), group 3: induced arthritis mice that received intravenous injection of MSCs. Betamethasone model, group 1: phosphate buffer saline, group 2: CIA, group 3: induced arthritis mice that received intraperitoneal injection of betamethasone. Mice arthritis models were assessed by clinical paw edema and X-rays, at the proper time of sacrefaction, tissues were collected and examined using real-time PCR, and synovial tissue was examined for interleukin-10, tumor necrosis factor α, cartilage oligomeric matrix protein and matrix metalloproteinase 3. While serum levels of rheumatoid factor and C-reactive protein were detected by enzyme-linked immunosorbent assay kits. Also blood erythrocyte sedimentation rate was detected. Histopathological, paw edema and PCR results showed improvement in the groups that received MSC compared with the diseased group and the groups which received betamethasone. MSC significantly enhanced the effect of collagen-induced arthritis treatment, which is superior to betamethasone treatment, likely through the modulation of the expression of various cytokines.

Shuangtengbitong tincture treatment of collagen-induced arthritis via downregulation of the expression of IL-6, IL-8, TNF-α and NF-κB

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease and may lead to joint damage, synovial membrane destruction and cartilage and bone damage. RA is closely associated with increased expression of interleukin (IL)-6, IL-8, tumor necrosis factor-α (TNF-α) and nuclear transcription factor-κB (NF-κB). Therefore, inhibition of the expression of IL-6, IL-8, TNF-α and NF-κB is a promising strategy for the development of novel anti-RA therapies. The aim of this study was to investigate the effect of shuangtengbitong tincture (STBT) on the expression of IL-6, IL-8, TNF-α and NF-κB in synovial tissues of rats with collagen-induced arthritis (CIA). STBT as a clinical prescription created at Fujian University of Traditional Chinese Medicines (TCM) Affiliated People’s Hospital has been shown to be clinically effective in the treatment of RA. The model of Wistar rats with CIA was created using bovine type II collagen. The two treatment groups with CIA were administered STBT (1 ml per time) or Votalin (∼1 cm per time) for ∼1 month continuously. Following treatment, STBT suppressed paw swelling significantly (P<0.05) compared with the model group. STBT also improved pathological changes, STBT-treated rats showed a significant improvement in synovial hyperplasia, inflammatory infiltration, cartilage and bone destruction and other symptoms. The protein expression levels of IL-6, IL-8, TNF-α and NF-κB were markedly suppressed in synovial tissues of STBT-treated and Votalin-treated rats. Our findings demonstrate for the first time that STBT markedly reduces paw swelling, improves pathological changes and increases the expression of IL-6, IL-8, TNF-α and NF-κB in synovial tissues of CIA rats, which may partially explain the anti-RA activity of STBT.

Mechanisms for redox actions of nicotine and glutathione in cell culture, relevant to periodontitis

The oxidative effect of nicotine was investigated using androgen biomarkers of redox status and wound healing in fibroblasts; using the antioxidant glutathione for confirmation of responses. Cultures of human gingival (HGF) and periosteal fibroblasts (HPF) were incubated with substrates 14C-testosterone/14C-4-androstenedione in the presence or absence of serial concentrations of nicotine (N_100-500), glutathione (G_1–5) and their combinations, in medium. At 24 h the medium was solvent extracted for metabolites, separated by TLC and quantified using radioisotope scanning. Nicotine caused significant inhibition in yields of the physiologically active metabolite 5α-dihydrotestosterone (DHT) in HGF and HPF, overcome to varying degrees by the anti-oxidant glutathione (n = 6; p<0.01, one way ANOVA); this is suggestive of moderation of an oxidative mechanism induced by nicotine. Down-regulation of 5α-reductase activity by nicotine resulting in reduced yields of DHT was overcome by glutathione. Overcoming oxidative stress in a redox environment is applicable to treatment outcome.

Anabolic Actions of the Regenerative Agent Enamel Matrix Derivative (EMD) in Oral Periosteal Fibroblasts and MG 63 Osteoblasts, Modulation by Nicotine and Glutathione in a Redox Environment

Our study seeks to explore anabolic effects of a periodontal regenerative agent enamel matrix derivative (EMD). Its modulation by nicotine and the anti-oxidant glutathione (GSH) are investigated in human periosteal fibroblasts (HPF) and MG63 osteoblasts. Androgen biomarkers of oxidative stress and healing, resulting from radiolabeled androgen substrates are assayed. This in vitro model simulates a redox environment relevant to the periodontal lesion. It aims to confirm the hypothesis that EMD is an effective regenerative agent in a typically redox environment of the periodontal lesion. Monolayer cultures of MG63 osteoblasts and HPF established in culture medium are incubated with androgen substrates, and optimal concentrations of EMD, nicotine and GSH, alone and in combination. EMD significantly enhances yields of 5α-dihydrotestosterone (DHT) an effective bioactive metabolite, alone and in combination with GSH, to overcome oxidative effects of nicotine across cultures. The ‘in vitro’ findings of this study could be extrapolated to “in vivo” applications of EMD as an adjunctive regenerative therapeutic agent in an environment of chronic inflammation and oxidative stress. Increased yields of DHT implicated in matrix synthesis and direct antioxidant capacity, confirm the potential applications for enamel matrix derivative in periodontal regenerative procedures.

Effects of testosterone, estrogen and progesterone on TNF-α mediated cellular damage in rat arthritic synovial fibroblasts

Sexual dimorphism is a well-established phenomenon in rheumatoid arthritis, with women exhibiting higher disease severity. Understanding the role of sex hormones using in vivo animal models is limited due to the systemic effects as well as the difficulty in exploring different dose combinations of the hormones simultaneously. However, cell culture systems pose ideal systems for exploring different combinations and concentrations of the hormones simultaneously. In this study, the procedure for isolation of arthritic fibroblasts was standardized using a combination of collagenase and trypsin based on maximal yield and viability after employing different enzymatic disaggregation procedures. The cultured synovial fibroblasts from arthritic rats did not differ significantly from normal rat fibroblasts in terms of proliferation or secretion of inflammatory mediators. Stimulation of fibroblasts with TNF-α was standardized and TNF-α stimulated rat arthritic synovial fibroblasts exhibited an ideal in vitro system for screening antiinflammatory molecules. The effects of physiological and pharmacological concentrations of testosterone, estrogen and progesterone were studied on TNF-α induced cellular damage in rat arthritic synovial fibroblasts. The results showed that estrogen and testosterone exerted antiinflammatory effects on rat arthritic synovial fibroblasts at physiological and pharmacological concentrations. However, there was no significant difference in the effects between physiological and pharmacological concentrations. Progesterone independently did not show any protective effects. In combination with physiological concentrations of estrogen, progesterone abrogated estrogen's protective effect but it exhibited protection in combination with pharmacological concentrations of estrogen.

Anti-inflammatory and anti-oxidant properties of Curcuma longa (turmeric) versus Zingiber officinale (ginger) rhizomes in rat adjuvant-induced arthritis

Turmeric (rich in curcuminoids) and ginger (rich in gingerols and shogaols) rhizomes have been widely used as dietary spices and to treat different diseases in Ayurveda/Chinese medicine since antiquity. Here, we compared the anti-inflammatory/anti-oxidant activity of these two plants in rat adjuvant-induced arthritis (AIA). Both plants (at dose 200 mg/kg body weight) significantly suppressed (but with different degrees) the incidence and severity of arthritis by increasing/decreasing the production of anti-inflammatory/pro-inflammatory cytokines, respectively, and activating the anti-oxidant defence system. The anti-arthritic activity of turmeric exceeded that of ginger and indomethacin (a non-steroidal anti-inflammatory drug), especially when the treatment started from the day of arthritis induction. The percentage of disease recovery was 4.6-8.3% and 10.2% more in turmeric compared with ginger and indomethacin (P < 0.05), respectively. The present study proves the anti-inflammatory/anti-oxidant activity of turmeric over ginger and indomethacin, which may have beneficial effects against rheumatoid arthritis onset/progression as shown in AIA rat model.

Effects of ovariectomy and resistance training on MMP-2 activity in rat calcaneal tendon

Tendon remodeling relies on extracellular matrix (ECM) restructuring by the matrix metallopeptidases (MMPs). The aim of this study was to investigate MMP-2 activity in different regions of the calcaneal tendon (CT) after resistance training (RT) in ovariectomized rats. Wistar adult female rats were grouped into sedentary (Sed-Intact), ovariectomized sedentary (Sed-Ovx), acute exercise (AcuteEx-Intact), ovariectomized acute exercise (AcuteEx-Ovx), resistance trained (ChronicEx-Intact), and ovariectomized resistance trained (ChronicEx-Ovx) (n = 10 each group). The RT protocol required the animals to climb a 1.1-m vertical ladder with weights attached to their tail. The sessions were performed once every 3 days with 4-9 climbs and 8-12 dynamic movements per scaling. The acute groups performed one session and the chronic groups underwent 12 weeks of RT. There was an increase in total MMP-2 activity in Sed-Ovx, AcuteEx-Intact, and ChronicEx-Intact compared with that in Sed-Intact in the proximal region of CT. AcuteEx-Ovx exhibited higher total MMP-2 than Sed-Ovx and AcuteEx-Intact in the distal region of CT. Chronic-Ovx presented lower total MMP-2 activity than Sed-Ovx and Chronic-Intact in the distal region of tendon. The active MMP-2 was higher for the AcuteEx-Ovx than Sed-Ovx and AcuteEx-Intact in proximal region of tendon. There was higher active MMP-2 in the distal region of tendon in the Acute-Ovx than in the Sed-Ovx and AcuteEx-Intact. Ovariectomy and resistance exercise modulate MMP-2 activity according to specific tendon region, indicating a differentiated tissue remodeling.

Dihydrotestosterone protects human vascular endothelial cells from H(2)O(2)-induced apoptosis through inhibition of caspase-3, caspase-9 and p38 MAPK

Oxidative stress is proved to be harmful to the vascular endothelial cells which are important in preventing the formation and progression of atheromatous plaque. This study was designed to investigate the protective effect and potential mechanisms of dihydrotestosterone (DHT) against H(2)O(2)-induced apoptosis of human umbilical vein endothelial cells (ECV-304). ECV-304 cells were pretreated with different concentrations of DHT (0.01, 0.1 and 1 microM) for 2h, followed by exposure to 100 microM H(2)O(2) for 18h. 3-(4,5-dimethylthiazol-2yl-)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate cell viability. To detect apoptosis, the cells were assessed by morphologic examination and Annexin V-propidium iodide double staining with flow cytometry. Finally, the expression of caspase-3, caspase-9 and phospho p38 MAPK was assayed by Western blot to investigate the possible molecular mechanisms. We found that H(2)O(2) treatment for 18h significantly decrease the viability of ECV-304 cells characterized by a high percentage of apoptotic cells. DHT could antagonize the apoptosis inducing effect of H(2)O(2) in a dose-dependent manner. Consistently, DHT also significantly inhibit the expression of caspase-3, caspase-9 and phospho p38 MAPK induced by H(2)O(2). In summary, pretreatment with DHT can inhibit apoptosis of ECV-304 cells induced by H(2)O(2). The protective effect of DHT was associated with the inhibition of caspase-3, caspase-9 and phospho p38 MAPK expression.

Endogenous estrogen regulation of inflammatory arthritis and cytokine expression in male mice, predominantly via estrogen receptor alpha

OBJECTIVE

A number of experimental observations have associated elevated estrogen levels with amelioration of inflammation. The involvement of estrogen and estrogen receptor (ER) isotypes in the regulation of inflammation in males is not well understood. In this study, we used specific ERalpha and ERbeta agonists in male mice deficient in estrogen because of a deletion of aromatase (aromatase-knockout [ArKO] mice) to investigate ER isotype utilization in estrogen regulation of inflammation.

METHODS

Lipopolysaccharide (LPS)-induced cytokine expression and antigen-induced arthritis (AIA) were investigated in male ArKO and WT littermate mice, as well as in response to selective agonists of ERalpha (16alpha-LE2) and ERbeta (8beta-VE2). The therapeutic effect of selective ER agonists was also examined in mice with collagen-induced arthritis (CIA).

RESULTS

Estrogen deficiency in ArKO mice was associated with significant increases in LPS-induced serum interleukin-6 (IL-6), tumor necrosis factor, monocyte chemotactic protein 1, and interferon-gamma levels, which were significantly abrogated by administration of 16alpha-LE2, but not 8beta-VE2. In contrast, both 16alpha-LE2 and 8beta-VE2 significantly increased LPS-induced IL-10 levels. Estrogen deficiency was also associated with significant exacerbation of AIA and antigen-specific T cell proliferation, which was reversed by administration of either 16alpha-LE2 or 8beta-VE2. ArKO mice showed increased antigen-specific T cell proliferation in response to immunization with type II collagen (CII). Administration of 16alpha-LE2, but not 8beta-VE2, significantly reduced the severity of CIA, which was associated with inhibition of anti-CII-specific IgG.

CONCLUSION

These data indicate that endogenous estrogen plays an essential inhibitory role in inflammation in male mice and that ERalpha is the dominant receptor that mediates these effects.

10-Hydroxy-2-decenoic acid from Royal jelly: a potential medicine for RA

AIM OF THE STUDY

Rheumatoid arthritis synovial fibroblasts (RASFs) are known to produce matrix metalloproteinases (MMPs) and cause joint destruction. The purpose of this study is to develop a potential medicine for rheumatoid arthritis (RA).

MATERIALS AND METHODS

To this end, first, the MMPs inhibition factor was purified from an alkali-solubilized fraction of RJ (Apis mellifera) by C18 reverse-phase column chromatography and identified as 10-hydroxy-2-decenoic acid (10H2DA) by LTQ XL analysis. Next, Experimental test 10H2DA how to inhibited the activities of MMPs: with RASFs isolated from rheumatoid tissues by enzymatic digestion, cultures in monolayers were treated with 10H2DA (0.5mM, 1mM, and 2mM) or PBS for 2h followed by stimulation with TNF-alpha (10 ng/ml) for 2h, mRNA. Protein levels of MMP-1 and MMP-3 were measured by real-time PCR and enzyme-linked immunosorbent assay (ELISA), the DNA-binding activity of activator protein-1 (AP-1) and nuclear factor kappaB (NF-kappaB) by electrophoretic mobility shift assay (EMSA), and the protein kinase activity of p38, ERK and JNK by kinase assay.

RESULTS

The molecular investigation revealed that the 10H2DA-mediated suppression was likely to occur through blocking p38 kinase and c-Jun N-terminal kinase-AP-1 signaling pathways. In contrast, 10H2DA had no effect on extracellular signal-regulated kinase activity, NF-kappaB DNA-binding activity and IkappaBalpha degradation.

CONCLUSION

These results suggest that 10H2DA may be of potential therapeutic value in inhibiting joint destruction in RA.

Anti-inflammatory effect of Sanshuibaihu decoction may be associated with nuclear factor-kappa B and p38 MAPK alpha in collagen-induced arthritis in rat

Sanshuibaihu decoction (SSBH) is an anti-arthritic Chinese herbal formula which has been used in the treatment of rheumatoid arthritis (RA) for many years. We herein aimed to confirm its anti-arthritic effect and explore the potential mechanism of action on collagen-induced arthritis (CIA) in rats. CIA was induced by immunizing 50 female Wistar rats with bovine type II collagen. 13 days following the immunization rats with CIA were treated with SSBH (50mg/kg), leflunomide (LEF) (10mg/kg) and physiological saline for 30 days, and rats without CIA were left untreated. After the treatment, paw edema was obviously improved in SSBH-treated rats, with the significant difference of arthritis score (F=6.032, P=0.006) observed between the three treated groups. In pathological observation, SSBH-treated rats showed a significant improvement of inflammatory infiltration, synovial hyperplasia, cartilage and bone destruction and joint fusion. After the treatment of SSBH, radiological score of knee (t=11.504, P=0.000) and ankle joints (t=9.250, P=0.000) was decreased significantly. In situ hybridization on joint tissue section indicated only slight synovial hyperblastosis and expression of NF-kappaB in SSBH-treated rats. Image analysis indicated a significant difference of means of integrated optical density (MIOD) (F=3.956, P=0.040) and means of stained area (MSA) (F=3.867, P=0.032) of NF-kappaB between the three treated groups. MIOD and MSA of SSBH-treated group were significantly lower vs control. Enzyme linked immunosorbent assay (ELISA) showed a significant difference (F=10.167, P=0.000) of the amount of p-p38 MAPKalpha in the three treated groups. The detected amount of p-p38 MAPKalpha in SSBH-treated group was significantly lower vs control. These results show SSBH has an inhibiting effect on CIA, which may be associated with NF-kappaB and p38 MAPKalpha.

Adipocyte extracellular matrix composition, dynamics and role in obesity

The central role of the adipose tissue in lipid metabolism places specific demands on the cell structure of adipocytes. The protein composition and dynamics of the extracellular matrix (ECM) is of crucial importance for the functioning of those cells. Adipogenesis is a bi-phasic process in which the ECM develops from a fibrillar to a laminar structure as cells move from the commitment phase to the growth phase characterized by storage of vast amounts of triglycerides. Mature adipocytes appear to spend a lot of energy on the maintenance of the ECM. ECM remodeling is mediated by a balanced complement of constructive and destructive enzymes together with their enhancers and inhibitors. ECM remodeling is an energy costing process regulated by insulin, by the energy metabolism, and by mechanical forces. In the obese, overgrowth of adipocytes may lead to instability of the ECM, possibly mediated by hypoxia.

Immunosuppressive effects of mesenchymal stem cells in collagen-induced mouse arthritis

OBJECTIVE

The objective of this study was to investigate the efficacy of mesenchymal stem cell (MSC) in the treatment of arthritis.

METHODS

Mesenchymal stem cells were injected intravenously into mice with collagen-induced arthritis (CIA). Arthritic indexes were evaluated, and the levels of the pro- and anti-inflammatory cytokines interleukin-10 (IL-10), gamma interferon (IFN-gamma)-inducible protein 10 (IP-10), chemokine (C-X-C motif) receptor 3 (CXCR3), interleukin-17A (IL-17A), and tumor necrosis factor alpha (TNF-alpha) in serum or splenic cells were determined using real-time RT-PCR, Western blotting, and enzyme-linked immunosorbent assay (ELISA). The proliferation of dendritic cell line D2SC cells was determined using (3)H-TdR incorporation assay.

RESULTS

Upon injection of MSCs, overall arthritis symptoms were significantly improved in the CIA mouse models as indicated by the paw edema. Consistent with this observation, serum levels of pro-inflammatory cytokine TNF-alpha and inflammatory cell infiltration decreased significantly 12 days after MSC injection, while the expression of anti-inflammatory cytokines IL-10, IP-10, and CXCR3 was increased in splenocytes. In addition, we provided evidence that MSCs may directly promote the proliferation of D2SC cells and the expression of IP-10 in D2SC cells in vitro.

CONCLUSION

Mesenchymal stem cells significantly enhance the efficacy of collagen-induced arthritis treatment, likely through the modulation of the expression of various cytokines.