Mendelian randomization analysis revealed a gut microbiota-eye axis in acute anterior uveitis

BACKGROUND

Observational studies suggest that gut microbiome (GM) may contribute to acute anterior uveitis (AAU) development, but causality remains unclear. This study was conducted to test whether specific GM taxa were causally associated with AAU.

METHODS

The GM data were obtained from the DMP, which included 7738 individuals' faecal samples and an analysis of host genotype-taxa abundance associations. The AAU data were derived from the FinnGen Consortium (8624 cases and 473,095 controls). We primarily employed the inverse-variance weighted method, complemented by supplementary sensitivity analyses.

RESULTS

Higher abundance of Lachnospiraceae noname (OR = 0.86, 95% CI 0.81-0.91, P = 5.7 × 10-8), Alistipes finegoldii (OR = 0.87, 95% CI 0.78-0.96, P = 0.008), Erysipelotrichaceae (OR = 0.90, 95% CI 0.81-0.99, P = 0.037), Erysipelotrichia (OR = 0.90, 95% CI 0.81-0.99, P = 0.037), Erysipelotrichales (OR = 0.90, 95% CI 0.81-0.99, P = 0.037), and Bacteroides ovatus (OR = 0.93, 95% CI 0.87-1.00, P = 0.039) predicted a lower AAU risk. Conversely, higher abundance of Bifidobacterium catenulatum (OR = 1.06, 95% CI: 1.02-1.10, P = 0.005), Bacteroides coprocola (OR = 1.11, 95% CI: 1.02-1.21, P = 0.014), Parabacteroides unclassified (OR = 1.12, 95% CI 1.03-1.22, P = 0.010), and Prevotella (OR = 1.15, 95% CI: 1.01-1.29, P = 0.029) predicted a higher AAU risk. The results also showed a reverse causation from AAU to Bifidobacterium catenulatum (OR = 1.39, 95% CI: 1.03-1.86, P = 0.005).

CONCLUSION

This study suggests that specific GM is causally associated with AAU risk, warranting more mechanistic validation and clinical trials.

Lactobacillus acidophilus and its metabolite ursodeoxycholic acid ameliorate ulcerative colitis by promoting Treg differentiation and inhibiting M1 macrophage polarization

Lactobacillus acidophilus (LA) is a common clinical probiotic that improves ulcerative colitis (UC) by restoring intestinal immune balance. However, the interaction of LA with the gut microbiota and its metabolites in the treatment of UC remains unknown. Therefore, this study seeks to elucidate whether the gut microbiota and its metabolites act as pivotal effectors in LA's therapeutic mechanisms and how precisely they modulate intestinal immunity. In this study, we verified that LA can obviously ameliorate the disease severity, and regulate intestinal immune disorders in UC mice. Subsequently, antibiotic (ABX)-mediated depletion of the gut microflora demonstrated that the therapeutic efficiency of LA was closely associated with gut microbiota. In addition, the results of metabolomics revealed that ursodeoxycholic acid (UDCA), a metabolite of intestinal flora, may be a potential effector molecule mediating therapeutic effects of LA. Indeed, we found that UDCA can improve the macro pathological characteristics of UC mice, and through a comprehensive set of in vivo and in vitro experiments, we discovered that UDCA exerts dual effects on immune regulation. Firstly, it promotes the differentiation of Treg cells, resulting in increased secretion of anti-inflammatory cytokines. Secondly, UDCA inhibits the polarization of M1 macrophages, effectively reducing the secretion of pro-inflammatory cytokines. Moreover, we found that UDCA regulation of immune response is directly related to the RapGap/PI3K-AKT/NF-κB signaling pathway. In conclusion, LA and its metabolite, UDCA, may treat UC by activating the RapGap/PI3K-AKT/NF-κB signaling pathway and modulating Treg cells and M1 macrophages. All in all, our findings highlight the potential of microbial metabolites in enhancing probiotic for UC treatment.

Stereotypic Expansion of T Regulatory and Th17 Cells during Infancy Is Disrupted by HIV Exposure and Gut Epithelial Damage

Few studies have investigated immune cell ontogeny throughout the neonatal and early pediatric period, when there is often increased vulnerability to infections. In this study, we evaluated the dynamics of two critical T cell populations, T regulatory (Treg) cells and Th17 cells, over the first 36 wk of human life. First, we observed distinct CD4+ T cells phenotypes between cord blood and peripheral blood, collected within 12 h of birth, showing that cord blood is not a surrogate for newborn blood. Second, both Treg and Th17 cells expanded in a synchronous fashion over 36 wk of life. However, comparing infants exposed to HIV in utero, but remaining uninfected, with HIV-unexposed uninfected control infants, there was a lower frequency of peripheral blood Treg cells at birth, resulting in a delayed expansion, and then declining again at 36 wk. Focusing on birth events, we found that Treg cells coexpressing CCR4 and α4β7 inversely correlated with plasma concentrations of CCL17 (the ligand for CCR4) and intestinal fatty acid binding protein, IL-7, and CCL20. This was in contrast with Th17 cells, which showed a positive association with these plasma analytes. Thus, despite the stereotypic expansion of both cell subsets over the first few months of life, there was a disruption in the balance of Th17 to Treg cells at birth likely being a result of gut damage and homing of newborn Treg cells from the blood circulation to the gut.

An immuno-blocking agent targeting IL-1β and IL-17A reduces the lesion of DSS-induced ulcerative colitis in mice

In recent decades when biological agents have flourished, a part of patients suffering from inflammatory bowel disease (IBD) have received the treatment of tumor necrosis factor inhibitors or IL-1 antibodies. This study aims to investigate the anti-colitis effects of bispecific antibody (FL-BsAb1/17) targeting IL-1β and IL-17A comparing with TNF-α soluble receptor medicine etanercept. IBD model in mice was established by drinking 3% DSS (dextran sulfate sodium salt). On the first day of drinking DSS, treatments with etanercept (5 mg/kg) or different doses of FL-BsAb1/17 (1 mg/kg, 5 mg/kg, and 10 mg/kg) were started by intraperitoneal injection every other day. The results demonstrated that FL-BsAb1/17 treatment was more effective than etanercept at the same dose (5 mg/kg) in relieving the typical symptom of ulcerative colitis induced by DSS (such as the severity score and intestinal shortening), and down-regulating the expression of inflammatory factors (IL-17A, IL-6, IL-12, IL-22, IL-1β, IL-23, TNF-α) in the serum and colon. FL-BsAb1/17 could also reduce the degree of intestinal fibrosis. The same dose of FL-BsAb1/17 (5 mg/kg) performed better than etanercept in down-regulating MDA and up-regulating SOD (superoxide dismutase), CAT (catalase), and T-AOC (total antioxidant capacity) in serum. Both FL-BsAb1/17 and etanercept could reduce the transcription of Bax and increase the transcription of Bcl-2 and slow down apoptosis in colitis colon tissue. We conclude that the blocking of IL-1β and IL-17A can inhibit DSS-induced ulcerative colitis and FL-BsAb1/17 may have potential to become a new dual-target candidate for colitis treatment.

Opportunities to Target T Cell Trafficking in Pediatric Inflammatory Bowel Disease

T cell subsets are considered central orchestrators of inflammation and homeostasis in the intestine and are established targets for the treatment of inflammatory bowel disease. While approaches aimed at the neutralization of T cell effector cytokines have provided significant benefits for pediatric and adult patients, more recent strategies aimed at inhibiting the infiltration of pathogenic T cell subsets have also emerged. In this review, we describe current knowledge surrounding the function of T cell subsets in pediatric inflammatory bowel disease and outline approaches aimed at targeting T cell trafficking to the intestine which may represent a new treatment option for pediatric inflammatory bowel disease.

The JAK2 inhibitor AG490 regulates the Treg/Th17 balance and alleviates DSS-induced intestinal damage in IBD rats

The pathogenesis of inflammatory bowel disease (IBD) remains unclear, and it is currently believed that an imbalance in regulatory T (Treg) cells/T helper 17 cells (Th17 cells) is related to the occurrence and development of IBD. Recently, the JAK2 inhibitor AG490 has been used in animal models such as rheumatoid arthritis and bronchial asthma models and shown to exert immunoregulatory functions that improve disorder in the Treg/Th17 cell balance. This study aimed to evaluate the effect of AG490 on the intestinal inflammatory process in an IBD rat model. A dextran sulfate sodium (DSS)-induced IBD rat model was established, and disease activity index (DAI) scores were calculated. The histopathological damage score was determined by haematoxylin-eosin (H&E) staining. Treg/Th17 cells in the spleen were detected by flow cytometry. The levels of interleukin (IL)-10, IL-6 and IL-17A were detected by enzyme-linked immunosorbent assay (ELISA). AG490 attenuated DSS-induced IBD injury by regulating the Treg/Th17 balance and related cytokine secretion to reduce the DAI and colonic tissue damage. Thus, AG490 may be a new method for effective treatment of IBD.

Exploiting the Zonulin Mouse Model to Establish the Role of Primary Impaired Gut Barrier Function on Microbiota Composition and Immune Profiles

The balanced interplay between epithelial barrier, immune system, and microbiota maintains gut homeostasis, while disruption of this interplay may lead to inflammation. Paracellular permeability is governed by intercellular tight-junctions (TJs). Zonulin is, to date, the only known physiological regulator of intestinal TJs. We used a zonulin transgenic mouse (Ztm) model characterized by increased small intestinal permeability to elucidate the role of a primary impaired gut barrier on microbiome composition and/or immune profile. Ztm exhibit an altered gene expression profile of TJs in the gut compared to wild-type mice (WT): Claudin-15, Claudin-5, Jam-3, and Myosin-1C are decreased in the male duodenum whereas Claudin-15, Claudin-7, and ZO-2 are reduced in the female colon. These results are compatible with loss of gut barrier function and are paralleled by an altered microbiota composition with reduced abundance of the genus Akkermansia, known to have positive effects on gut barrier integrity and strengthening, and an increased abundance of the Rikenella genus, associated to low-grade inflammatory conditions. Immune profile analysis shows a subtly skewed distribution of immune cell subsets toward a pro-inflammatory phenotype with more IL-17 producing adaptive and innate-like T cells in Ztm. Interestingly, microbiota “normalization” involving the transfer of WT microbiota into Ztm, did not rescue the altered immune profile. Our data suggest that a primary impaired gut barrier causing an uncontrolled trafficking of microbial products leads to a latent pro-inflammatory status, with a skewed microbiota composition and immune profile that, in the presence of an environmental trigger, as we have previously described (1), might promote the onset of overt inflammation and an increased risk of chronic disease.

Kuijieling-Containing Serum Regulates Th17 and Treg Cell Differentiation by Inhibiting STAT3 Signaling In Vitro

Object

To investigate the effect of Kuijieling (KJL) on the balance between T helper 17 (Th17) and regulatory T (Treg) cells in peripheral blood mononuclear cells (PBMC) in vitro and explore the underlying mechanism.

Materials and Methods

PBMCs isolated from rats were stimulated with transforming growth factor-β, interleukin (IL)-6, and IL-23 to induce the imbalance of Th17 and Treg cells and were treated with 10, 5, or 2.5% KJL-containing serum. The proportion of Th17 or Treg cells in CD4⁺ T cells was analyzed by flow cytometry, the concentrations of IL-17, IL-21, and IL-10 were assayed by ELISA, mRNA expressions of retinoic acid-related orphan receptor γt (RORγt), forkhead box protein 3 (Foxp3), and signal transducer and activator of transcription 3 (STAT3) were quantified by PCR, and phosphorylated STAT3 (p-STAT3) was analyzed by flow cytometry.

Results

KJL-containing serum decreased the proportion of Th17 cells and increased the proportion of Treg cells in CD4⁺ T cells, decreased the concentration of IL-17 and IL-21, enhanced the level of IL-10 in the cell culture supernatant, promoted the expression of Foxp3, and inhibited the levels of RORγt, STAT3, and p-STAT3.

Conclusion

KJL suppresses the STAT3 pathway to remedy the imbalance between Th17 and Treg cells.

Mucosal Immunity Related to FOXP3+ Regulatory T Cells, Th17 Cells and Cytokines in Pediatric Inflammatory Bowel Disease

BACKGROUND

We aimed to investigate mucosal immunity related to forkhead box P3 (FOXP3+) regulatory T (Treg) cells, T helper 17 (Th17) cells and cytokines in pediatric inflammatory bowel disease (IBD).

METHODS

Mucosal tissues from terminal ileum and colon and serum samples were collected from twelve children with IBD and seven control children. Immunohistochemical staining was done using anti-human FOXP3 and anti-RORγt antibodies. Serum levels of cytokines were analyzed using a multiplex assay covering interleukin (IL)-1β, IL-4, IL-6, IL-10, IL-17A/F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, interferon (IFN)-γ, soluble CD40L, and tumor necrosis factor-α.

RESULTS

FOXP3+ Treg cells in the lamina propria (LP) of terminal ileum of patients with Crohn's disease were significantly (P < 0.05) higher than those in the healthy controls. RORγt+ T cells of terminal ileum tended to be higher in Crohn's disease than those in the control. In the multiplex assay, serum concentrations (pg/mL) of IL-4 (9.6 ± 1.5 vs. 12.7 ± 3.0), IL-21 (14.9 ± 1.5 vs. 26.4 ± 9.1), IL-33 (14.3 ± 0.9 vs. 19.1 ± 5.3), and IFN-γ (15.2 ± 5.9 vs. 50.2 ± 42.4) were significantly lower in Crohn's disease than those in the control group. However, serum concentration of IL-6 (119.1 ± 79.6 vs. 52.9 ± 39.1) was higher in Crohn's disease than that in the control. Serum concentrations of IL-17A (64.2 ± 17.2 vs. 28.3 ± 10.0) and IL-22 (37.5 ± 8.8 vs. 27.2 ± 3.7) were significantly higher in ulcerative colitis than those in Crohn's disease.

CONCLUSION

Mucosal immunity analysis showed increased FOXP3+ T reg cells in the LP with Crohn's disease while Th17 cell polarizing and signature cytokines were decreased in the serum samples of Crohn's disease but increased in ulcerative colitis.

T helper 17 cell/regulatory T-cell imbalance in hidradenitis suppurativa/acne inversa: the link to hair follicle dissection, obesity, smoking and autoimmune comorbidities

BACKGROUND

Disintegration of the infundibula of terminal hair follicles (HFs) in intertriginous skin areas exhibits the histological hallmark of hidradenitis suppurativa (HS)/acne inversa, featuring a dissecting terminal hair folliculitis. Elevated serum levels of interleukin (IL)-17 and local increase in the ratio of proinflammatory T helper (Th)17 cells and anti-inflammatory regulatory T cells (Tregs) have been reported. Perifollicular Tregs play a key role in HF stem cell homeostasis and infundibular integrity.

OBJECTIVES

In this review, we evaluate the Th17/Treg ratio in HS, its aggravating conditions and associated comorbidities. Furthermore, we intended to clarify whether drugs with reported beneficial effects in the treatment of HS readjust the deviated Th17/Treg axis.

METHODS

PubMed-listed, peer-reviewed original research articles characterizing Th17/Treg regulation in HS/acne inversa and associated comorbidities were selected for this review.

RESULTS

This review presents HS as a disease that exhibits an increased Th17/Treg ratio. Perifollicular deficiencies in Treg numbers or function may disturb HF stem cell homeostasis, initiating infundibular dissection of terminal HFs and perifollicular inflammation. The Th17/Treg imbalance is aggravated by obesity, smoking and decreased Notch signalling. In addition, HS-associated autoimmune diseases exhibit a disturbed Th17/Treg axis resulting in a Th17-dominant state. All drugs that have beneficial effects in the treatment of HS normalize the Th17/Treg ratio.

CONCLUSIONS

HS immunopathogenesis is closely related to deviations of the Th17/Treg balance, which may negatively affect Treg-controlled HF stem cell homeostasis and infundibular integrity. Pharmacological intervention should not only attenuate Th17/IL-17 signalling, but should also improve Treg function in order to stabilize HF stem cell homeostasis and infundibular integrity.

Strain differences in intestinal toxicity of warfarin in rats

Intestinal hemorrhage characterizes effectiveness of warfarin (WF) as rodenticide and is among adverse effects of therapy in humans. Having in mind genetic variations in the effectiveness of WF in wild rats and in the doses required for therapeutic effect, strain differences in the intestinal toxicity of oral warfarin in rats were examined in this study. High WF dose (3.5mg/l) led to mortality in Albino Oxford (AO) rats, with no lethality in Dark Agouti (DA) rats. Higher values of prothrombin time were noted at low WF dose (0.35mg/l) in the former strain. Leukocyte infiltration in intestine noted at this dose in both strains was associated with oxidative injury and more pronounced anti-oxidative response in AO rats. Suppression of mesenteric lymph node cell proliferation and IFN-γ and IL-10 production in AO rats and lack of these effects in DA rats, represent different strategies to protect vulnerable intestine from harmful immune responses.

Donor-Specific Regulatory T Cells Acquired from Tolerant Mice Bearing Cardiac Allograft Promote Mixed Chimerism and Prolong Intestinal Allograft Survival

The induction of donor-specific transplant tolerance has always been a central problem for small bowel transplantation (SBT), which is thought to be the best therapy for end-stage bowel failure. With the development of new tolerance-inducing strategies, mixed chimerism induced by co-stimulation blockade has become most potent for tolerance of allografts, such as skin, kidney, and heart. However, a lack of clinically available co-stimulation blockers has hindered efficient application in humans. Furthermore, unlike those for other types of solid organ transplantation, strategies to induce robust mixed chimerism for intestinal allografts have not been fully developed. To improve current mixed chimerism induction protocols for future clinical application, we developed a new protocol using donor-specific regulatory T (Treg) cells from mice with heart allograft tolerance, immunosuppressive drugs which could be used clinically and low doses of irradiation. Our results demonstrated that donor-specific Treg cells acquired from tolerant mice after in vitro expansion generate stable chimerism and lead to acceptance of intestinal allograft. Increased intragraft Treg cells and clonal deletion contribute to the development of SBT tolerance.

Non-small-cell lung cancer-induced immunosuppression by increased human regulatory T cells via Foxp3 promoter demethylation

Patients with non-small-cell lung cancer (NSCLC) have immune defects that are poorly understood. Forkhead box protein P3 (Foxp3) is crucial for immunosuppression by CD4(+) regulatory T cells (Tregs). It is not well known how NSCLC induces Foxp3 expression and causes immunosuppression in tumor-bearing patients. Our study found a higher percentage of CD4(+) Tregs in the peripheral blood of NSCLC compared with healthy donors. NSCLC patients showed demethylation of eight CpG sites within the Foxp3 promoter with methylation ratios negatively correlated with CD4(+)CD25(+)Foxp3(+) T levels. Foxp3 expression in CD4(+) Tregs was directly regulated by Foxp3 promoter demethylation and was involved in immunosuppression by NSCLC. To verify the effect of tumor cells on the phenotype and function of CD4(+) Tregs, we established a coculture system using NSCLC cell line and healthy CD4(+) T cells and showed that SPC-A1 induced IL-10 and TGF-β1 secretion by affecting the function of CD4(+) Tregs. The activity of DNA methyltransferases from CD4(+) T was decreased during this process. Furthermore, eight CpG sites within the Foxp3 promoter also appeared to have undergone demethylation. Foxp3 is highly expressed in CD4(+) T cells, and this may be caused by gene promoter demethylation. These induced Tregs are highly immunosuppressive and dramatically inhibit the proliferative activity of naïve CD4(+) T cells. Our study provides one possible mechanism describing Foxp3 promoter demethylation changes by which NSCLC down-regulates immune responses and contributes to tumor progression. Foxp3 represents an important target for NSCLC anti-tumor immunotherapy.

Neomangiferin modulates the Th17/Treg balance and ameliorates colitis in mice

BACKGROUND

Anemarrhena asphodeloides (Liliaceae family) and Mangifera indica L. (Anacardiaceae family) contain neomangiferin as the main active constituent and have been used to treat inflammation, asthma, and pain.

PURPOSE

A preliminary study found that neomangiferin inhibited splenic T cell differentiation into Th17 cells and promoted Treg cell production in vitro. Therefore, we examined its anti-colitic effects in vitro and in vivo.

METHODS

Splenocytes isolated from C57BL/6J mice were treated with neomangiferin. Colitis was either induced in vivo by intrarectal administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS) to C57BL/6J mice or occurred spontaneously in colitis caused by interleukin (IL)-10 knockout at age of 13 weeks. Mice were treated daily with neomangiferin or sulfasalazine. Inflammatory markers, cytokines, enzymes and transcription factors were measured by enzyme-linked immunosorbent assay, immunoblot, and flow cytometry.

RESULTS

Neomangiferin suppressed retinoic acid receptor-related orphan receptor gamma t (RORγt) and IL-17 expression in IL-6/transforming growth factor β-stimulated Th17 splenocytes and increased IL-10 expression in vitro. Mouse TNBS-induced colon shortening, macroscopic score, and myeloperoxidase activity were inhibited by neomangiferin, which also reduced TNBS-induced activation of nuclear factor-κB and extracellular signal-regulated kinases, as well as expression of inducible nitric oxide synthase and cyclooxygenase-2. In addition, neomangiferin inhibited TNBS-induced expression of tumor necrosis factor-α, IL-17, IL-6, and IL-1β, and increased IL-10 expression. Neomangiferin inhibited TNBS-induced differentiation to Th17 cells and promoted the development of Treg cells. Moreover, in IL-10(-/-) mice, neomangiferin inhibited colonic myeloperoxidase activity, suppressed Th17 cell differentiation, and reduced levels of TNF-α and IL-17.

CONCLUSION

Neomangiferin may restore the balance between Th17/Treg cells by suppressing IL-17 and RORγt expression and inducing IL-10 and forkhead box P3 expression, thus ameliorating colitis.

Antibiotics and the Human Gut Microbiome: Dysbioses and Accumulation of Resistances

The human microbiome is overly exposed to antibiotics, due, not only to their medical use, but also to their utilization in farm animals and crops. Microbiome composition can be rapidly altered by exposure to antibiotics, with potential immediate effects on health, for instance through the selection of resistant opportunistic pathogens that can cause acute disease. Microbiome alterations induced by antibiotics can also indirectly affect health in the long-term. The mutualistic microbes in the human body interact with many physiological processes, and participate in the regulation of immune and metabolic homeostasis. Therefore, antibiotic exposure can alter many basic physiological equilibria, promoting long-term disease. In addition, excessive antibiotic use fosters bacterial resistance, and the overly exposed human microbiome has become a significant reservoir of resistance genes, contributing to the increasing difficulty in controlling bacterial infections. Here, the complex relationships between antibiotics and the human microbiome are reviewed, with focus on the intestinal microbiota, addressing (1) the effects of antibiotic use on the composition and function of the gut microbiota, (2) the impact of antibiotic-induced microbiota alterations on immunity, metabolism, and health, and (3) the role of the gut microbiota as a reservoir of antibiotic resistances.

Changes in the cytokine expression of peripheral Treg and Th17 cells in children with rotavirus enteritis

The aim of the present study was to investigate the changes in the cytokine expression of peripheral regulatory T cells (Treg) and T helper 17 (Th17) cells in children with rotavirus (RV) enteritis. In total, 102 children with RV enteritis were recruited for the observation group, while 30 healthy cases were included in the control group. Peripheral blood samples were collected from the individuals in the two groups, after which flow cytometry was conducted to detect the proportion of Treg and Th17 cells. In addition, ELISA was used to determine the levels of the cytokines, interleukin (IL)-10, transforming growth factor (TGF)-β, IL-17 and IL-6. When compared with the control group, the proportion of Treg cells and level of TGF-β in the peripheral blood of the children with RV enteritis were significantly decreased (P<0.05); however, the proportion of Th17 cells and the serum levels of IL-17 and IL-6 in the peripheral blood of children with RV enteritis were significantly increased (P<0.05). In conclusion, the present study identified an imbalance in the proportion of peripheral blood Treg/Th17 cells, and subsequently in the expression of cytokines, in children with RV enteritis. Thus, detecting the proportion of peripheral blood Treg/Th17 cells in children with RV enteritis, or the changes in the levels of serum cytokines, is of clinical significance for further investigation into the pathogenesis of RV enteritis.

Regulatory effect of traditional Chinese medicinal formula Zuo-Gui-Wan on the Th17/Treg paradigm in mice with bone loss induced by estrogen deficiency

ETHNOPHARMACOLOGICAL RELEVANCE

Bone loss is a common pathological condition induced by estrogen deficiency. The Th17/Treg paradigm, which can be skewed by estrogen, plays an important role in regulating bone metabolism

AIM OF THE STUDY

The purpose of this study was to determine the role of the Th17/Treg shift in estrogen deficiency-induced bone loss in mouse models and to elucidate the immunopharmacologic mechanism of Zuo-Gui-Wan (ZGW) in preventing bone loss in this process by regulating Th17/Treg paradigm.

MATERIALS AND METHODS

Splenocytes of ovariectomized (Ovx) mice and naturally aged mice were isolated and Flow cytometry was used to detect the Th17/Treg subsets. In addition, serum estrodiol (E2) and serum C-terminal telopeptides of type Ι collagen (CTx) were detected by ELISA assay. Bone mineral density (BMD) of the left tibiae was measured by dual-energy X-ray absorptiometry. Moreover, Ovx mice were administrated with different doses of ZGW for 12 weeks, and BMD and Th17/Treg subsets were determined. Bone histomorphometry was observed by Hematoxylin and eosin (H&E) staining and serum protein levels of IL-6 were analyzed by ELISA assay. In addition, the mRNA and protein expression of RORγt and Foxp3 were detected by RT-PCR and Western blot respectively.

RESULT

The Th17/Treg paradigm shifted to Th17 in estrogen-deficient mice both in the Ovx mice and the naturally aged mice. BMD and E2 levels negatively correlated with the Th17/Treg ratio. After ZGW administration, the BMD was enhanced markedly in the Ovx mice as well as in the naturally aged mice. Both the mRNA and protein expressions of IL-6 and RORγt were decreased, whereas those of Foxp3 were increased significantly after ZGW administration.

CONCLUSION

Th17/Treg shift involved in the bone loss induced by estrogen deficiency. ZGW prevented bone loss efficiently and skewed Th17/Treg paradigm towards Treg without enhancing E2.