A Superparamagnetic Composite Hydrogel Scaffold as In Vivo Dynamic Monitorable Theranostic Platform for Osteoarthritis Regeneration.

Osteoarthritis (OA) is a prevalent disease, characterized by subchondral fractures in its initial stages, which has no precise and specific treatment now. Here, a novel multifunctional scaffold is synthesized by photopolymerizing glycidyl methacrylate-modified hyaluronic acid (GMHA) as the matrix in the presence of hollow porous magnetic microspheres based on hydroxyapatite. In vivo subchondral bone repairing results demonstrate that the scaffold's meticulous design has most suitable properties for subchondral bone repair. The porous structure of inorganic particles within the scaffold facilitates efficient transport of loaded exogenous vascular endothelial growth factor (VEGF). The Fe3O4 nanoparticles assembled in microspheres promote the osteogenic differentiation of bone marrow mesenchymal stem cells and accelerate the new bone generation. These features enable the scaffold to exhibit favorable subchondral bone repair properties and attain high cartilage repair scores. The therapy results prove that the subchondral bone support considerably influences the upper cartilage repair process. Furthermore, magnetic resonance imaging monitoring demonstrates that Fe3O4 nanoparticles, which are gradually replaced by new bone during osteochondral defect repair, allow a noninvasive and radiation-free assessment to track the newborn bone during the OA repair process. The composite hydrogel scaffold (CHS) provides a versatile platform for biomedical applications in OA treatment.

Celastrol ameliorates hypoxic-ischemic brain injury in neonatal rats by reducing oxidative stress and inflammation.

BACKGROUND: Hypoxic-ischemic encephalopathy (HIE) is caused by perinatal hypoxia and subsequent reductions in cerebral blood flow and is one of the leading causes of severe disability or death in newborns. Despite its prevalence, we currently lack an effective drug therapy to combat HIE. Celastrol (Cel) is a pentacyclic triterpene extracted from Tripterygium Wilfordi that can protect against oxidative stress, inflammation, and cancer. However, whether Cel can alleviate neonatal hypoxic-ischemic (HI) brain damage remains unclear. METHODS: Here, we established both in vitro and in vivo models of HI brain damage using CoCl2-treated PC12 cells and neonatal rats, respectively, and explored the neuroprotective effects of Cel in these models. RESULTS: Analyses revealed that Cel administration reduced brain infarction size, microglia activation, levels of inflammation factors, and levels of oxidative stress markers by upregulating levels of p-AMPKα, Nrf2, HO-1, and by downregulating levels of TXNIP and NLRP3. Conversely, these beneficial effects of Cel on HI brain damage were largely inhibited by AMPKα inhibitor Compound C and its siRNA. CONCLUSIONS: We present compelling evidence that Cel decreases inflammation and oxidative stress through the AMPKα/Nrf2/TXNIP signaling pathway, thereby alleviating neonatal HI brain injury. Cel therefore represents a promising therapeutic agent for treating HIE. IMPACT: We firstly report that celastrol can ameliorate neonatal hypoxic-ischemic brain injury both in in vivo and in vitro, which represents a promising therapeutic agent for treating related brain injuries. Celastrol activates the AMPKα/Nrf2/TXNIP signaling pathway to relieve oxidative stress and inflammation and thereby alleviates neonatal hypoxic-ischemic brain injury.

Mechanisms of Allosteric Inhibition of Insulin-Regulated Aminopeptidase.

Inhibition of Insulin-Regulated Aminopeptidase is being actively explored for the treatment of several human diseases and several classes of inhibitors have been developed although no clinical applications have been reported yet. Here, we combine enzymological analysis with x-ray crystallography to investigate the mechanism employed by two of the most studied inhibitors of IRAP, an aryl sulfonamide and a 2-amino-4H-benzopyran named HFI-419. Although both compounds have been hypothesized to target the enzyme's active site by competitive mechanisms, we discovered that they instead target previously unidentified proximal allosteric sites and utilize non-competitive inhibition mechanisms. X-ray crystallographic analysis demonstrated that the aryl sulfonamide stabilizes the closed, more active, conformation of the enzyme whereas HFI-419 locks the enzyme in a semi-open, and likely less active, conformation. HFI-419 potency is substrate-dependent and fails to effectively block the degradation of the physiological substrate cyclic peptide oxytocin. Our findings demonstrate alternative mechanisms for inhibiting IRAP through allosteric sites and conformational restricting and suggest that the pharmacology of HFI-419 may be more complicated than initially considered. Such conformation-specific interactions between IRAP and small molecules can be exploited for the design of more effective second-generation allosteric inhibitors.

Scribble deficiency mediates colon inflammation by inhibiting autophagy-dependent oxidative stress elimination.

Scribble is a master scaffold protein in apical-basal polarity. Current knowledge about the biological function of Scribble in colonic epithelial plasticity/regeneration during intestinal inflammation is limited. Here, we showed that the level of Scribble is decreased in inflammatory bowel disease (IBD) patients and mice with DSS-induced colitis. ScribΔIEC mice develops severe acute colitis with disrupted epithelial barrier integrity and impaired crypt stem cell's function. Mechanistically, Scribble suppressed the process of autophagy by modulating the stability of caspase-dependent degradation of Atg16L1 by directly interacting with Atg16L1 in a LRR domain-dependent manner in IECs and led to an accumulation of ROS both in intestinal stem cells and epithelial cells. In addition, further study indicates that dietary sphingomyelin alleviates DSS-induced colitis by increase the expression of Scribble, which suggests that Scribble may be the critical marker of IBD. Our study shows that Scribble deficiency is associated with the dysregulated autophagy and impaired maintenance of colonic stemness, and it may be a target for diagnosis and treatment of IBD.

Myricetin attenuates hypoxic-ischemic brain damage in neonatal rats via NRF2 signaling pathway.

Introduction: Hypoxic-ischemic encephalopathy (HIE) is a crucial cause of neonatal death and neurological sequelae, but currently there is no effective therapy drug for HIE. Both oxidative stress and apoptosis play critical roles in the pathological development of HIE. Myricetin, a naturally extracted flavonol compound, exerts remarkable effects against oxidative stress, apoptosis, and inflammation. However, the role and underlying molecular mechanism of myricetin on HIE remain unclear. Methods: In this study, we established the neonatal rats hypoxic-ischemic (HI) brain damage model in vivo and CoCl2 induced PC12 cell model in vitro to explore the neuroprotective effects of myricetin on HI injury, and illuminate the potential mechanism. Results: Our results showed that myricetin intervention could significantly reduce brain infarction volume, glia activation, apoptosis, and oxidative stress marker levels through activating NRF2 (Nuclear factor-E2-related factor 2) and increase the expressions of NRF2 downstream proteins NQO-1 and HO-1. In addition, the NRF2 inhibitor ML385 could significantly reverse the effects of myricetin. Conclusion: This study found that myricetin might alleviate oxidative stress and apoptosis through NRF2 signaling pathway to exert the protective role for HI injury, which suggested that myricetin might be a promising therapeutic agent for HIE.

Broadly recognized, cross-reactive SARS-CoV-2 CD4 T cell epitopes are highly conserved across human coronaviruses and presented by common HLA alleles.

Sequence homology between SARS-CoV-2 and common-cold human coronaviruses (HCoVs) raises the possibility that memory responses to prior HCoV infection can affect T cell response in COVID-19. We studied T cell responses to SARS-CoV-2 and HCoVs in convalescent COVID-19 donors and identified a highly conserved SARS-CoV-2 sequence, S811-831, with overlapping epitopes presented by common MHC class II proteins HLA-DQ5 and HLA-DP4. These epitopes are recognized by low-abundance CD4 T cells from convalescent COVID-19 donors, mRNA vaccine recipients, and uninfected donors. TCR sequencing revealed a diverse repertoire with public TCRs. T cell cross-reactivity is driven by the high conservation across human and animal coronaviruses of T cell contact residues in both HLA-DQ5 and HLA-DP4 binding frames, with distinct patterns of HCoV cross-reactivity explained by MHC class II binding preferences and substitutions at secondary TCR contact sites. These data highlight S811-831 as a highly conserved CD4 T cell epitope broadly recognized across human populations.

Association of MTHFR Polymorphisms with H-Type Hypertension: A Systemic Review and Network Meta-Analysis of Diagnostic Test Accuracy.

Purpose: An association between MTHFR polymorphisms and H-type hypertension (H-HTN) has been investigated by epidemiological studies, but results have been inconsistent. Thus, a systematic assessment of the association was performed based on a literature review and pooled analysis, to provide stronger evidence on the effects of single nucleotide polymorphisms on H-HTN risk. Methods: Three investigators independently retrieved relevant studies in PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), Wanfang Database, and China Biomedical Literature Database (CBM). A fixed or random effects model was selected to calculate pooled odds ratio (OR) and 95% confidence intervals (CIs). A network meta-analysis of diagnostic test and Thakkinstian's algorithm were used to select the most appropriate genetic model, along with false-positive report probability (FPRP) for noteworthy associations. All data were processed using Stata 15.0 and Meta-Disc. Results: A total of 14 studies involving 1759 cases and 1581 controls for MTHFR were included in our meta-analysis. In a direct meta-analysis, we found that MTHFR C667T rs1801133 significantly increased the risk of H-HTN susceptibility except for an overdominant model. However, MTHFR A1298C rs1801131 polymorphism had no significant correlation with H-HTN risk. Besides, MTHFR C667T rs1801133 is a potential diagnostic biomarker for estimating H-HTN risk. The results indicated that the dominant model was an optimal diagnosis model for excluding diseases, which could reduce a missed diagnosis rate and further improve the accuracy of disease diagnosis. Conclusion: The present result suggests that MTHFR C667T rs1801133 polymorphism is associated with H-HTN risk and may act as a promising predictive biomarker for H-HTN risk. However, further well-designed studies are warranted to confirm these results.

Lin28B-high breast cancer cells promote immune suppression in the lung pre-metastatic niche via exosomes and support cancer progression.

The formation of pre-metastatic niche is a key step in the metastatic burden. The pluripotent factor Lin28B is frequently expressed in breast tumors and is particularly upregulated in the triple negative breast cancer subtype. Here, we demonstrate that Lin28B promotes lung metastasis of breast cancer by building an immune-suppressive pre-metastatic niche. Lin28B enables neutrophil recruitment and N2 conversion. The N2 neutrophils are then essential for immune suppression in pre-metastatic lung by PD-L2 up-regulation and a dysregulated cytokine milieu. We also identify that breast cancer-released exosomes with low let-7s are a prerequisite for Lin28B-induced immune suppression. Moreover, Lin28B-induced breast cancer stem cells are the main sources of low-let-7s exosomes. Clinical data further verify that high Lin28B and low let-7s in tumors are both indicators for poor prognosis and lung metastasis in breast cancer patients. Together, these data reveal a mechanism by which Lin28B directs the formation of an immune-suppressive pre-metastatic niche.

An enhanced EEG microstate recognition framework based on deep neural networks: an application to Parkinson's disease.

Variations in brain activity patterns reveal impairments of motor and cognitive functions in the human brain. Electroencephalogram (EEG) microstates embody brain activity patterns at a microscopic time scale. However, current microstate analysis method can only recognize less than 90% of EEG signals per subject, which severely limits the characterization of dynamic brain activity. As an application to early Parkinson's disease (PD), we propose an enhanced EEG microstate recognition framework based on deep neural networks, which yields recognition rates from 90% to 99%, as accompanied by a strong anti-artifact property. Additionally, gradient-weighted class activation mapping, as a visualization technique, is employed to locate the activated functional brain regions of each microstate class. We find that each microstate class corresponds to a particular activated brain region. Finally, based on the improved identification of microstate sequences, we explore the EEG microstate characteristics and their clinical associations. We show that the decreased occurrences of a particular microstate class reflect the degree of cognitive decline in early PD, and reduced transitions between certain microstates suggest injury in motor-related brain regions. The novel EEG microstate recognition framework paves the way to revealing more effective biomarkers for early PD.

Molecular mechanisms underlying hematophagia revealed by comparative analyses of leech genomes.

BACKGROUND: Leeches have been used in traditional Chinese medicine since prehistoric times to treat a spectrum of ailments, but very little is known about their physiological, genetic, and evolutionary characteristics. FINDINGS: We sequenced and assembled chromosome-level genomes of 3 leech species (bloodsucking Hirudo nipponia and Hirudinaria manillensis and nonbloodsucking Whitmania pigra). The dynamic population histories and genome-wide expression patterns of the 2 bloodsucking leech species were found to be similar. A combined analysis of the genomic and transcriptional data revealed that the bloodsucking leeches have a presumably enhanced auditory sense for prey location in relatively deep fresh water. The copy number of genes related to anticoagulation, analgesia, and anti-inflammation increased in the bloodsucking leeches, and their gene expressions responded dynamically to the bloodsucking process. Furthermore, the expanded FBN1 gene family may help in rapid body swelling of leeches after bloodsucking, and the expanded GLB3 gene family may be associated with long-term storage of prey blood in a leech's body. CONCLUSIONS: The high-quality reference genomes and comprehensive datasets obtained in this study may facilitate innovations in the artificial culture and strain optimization of leeches.

Association between Toll-like receptor gene polymorphisms and risk of Helicobacter pylori infection: A protocol for systematic review and meta-analysis.

BACKGROUND: There were many case-control studies performed the association between TLRs gene polymorphisms and the correlation of Helicobactor pylori infection, these results were inconformity. Therefore, a comprehensive meta-analysis was performed to evaluate the TLRs gene polymorphism and susceptibility to H. pylori infection. METHODS: Eligible studies were searched from PubMed, EMBASE, Web of science, Cochrane library, CNKI, CBM, Wan Fang Database and VIP Database, all the databases were searched from inception to December 2020. OR with the corresponding 95% CI were presented as associations between certain TLR gene polymorphism and the risk of H. pylori infection, all the included data will be analyzed with the software of Review Manager 5.2 and STATA 14.2. RESULTS: This study will provide a high-quality evidence to find the TLR gene polymorphisms with H. pylori infection susceptibility. CONCLUSION: This study will explore which TLR genotype increase the risk of H. pylori infection.

Distinguishing Signal From Noise in Immunopeptidome Studies of Limiting-Abundance Biological Samples: Peptides Presented by I-Ab in C57BL/6 Mouse Thymus.

Antigen presentation by MHC-II proteins in the thymus is central to selection of CD4 T cells, but analysis of the full repertoire of presented peptides responsible for positive and negative selection is complicated by the low abundance of antigen presenting cells. A key challenge in analysis of limiting abundance immunopeptidomes by mass spectrometry is distinguishing true MHC-binding peptides from co-eluting non-specifically bound peptides present in the mixture eluted from immunoaffinity-purified MHC molecules. Herein we tested several approaches to minimize the impact of non-specific background peptides, including analyzing eluates from isotype-control antibody-conjugated beads, considering only peptides present in nested sets, and using predicted binding motif analysis to identify core epitopes. We evaluated these methods using well-understood human cell line samples, and then applied them to analysis of the I-Ab presented immunopeptidome of the thymus of C57BL/6 mice, comparing this to the more easily characterized splenic B cell and dendritic cell populations. We identified a total of 3473 unique peptides eluted from the various tissues, using a data dependent acquisition strategy with a false-discovery rate of <1%. The immunopeptidomes presented in thymus as compared to splenic B cells and DCs identified shared and tissue-specific epitopes. A broader length distribution was observed for peptides presented in the thymus as compared to splenic B cells or DCs. Detailed analysis of 61 differentially presented peptides indicated a wider distribution of I-Ab binding affinities in thymus as compared to splenic B cells. These results suggest different constraints on antigen processing and presentation pathways in central versus peripheral tissues.

Macrophage-derived EDA-A2 inhibits intestinal stem cells by targeting miR-494/EDA2R/ß-catenin signaling in mice.

The mucosa microenvironment is critical for intestinal stem cell self-renewal and reconstruction of the epithelial barrier in inflammatory bowel disease (IBD), where the mechanisms underlying cross-talk between intestinal crypts and the microenvironment remain unclear. Here, we firstly identified miR-494-3p as an important protector in colitis. miR-494-3p levels were decreased and negatively correlated with the severity in human IBD samples, as well as in colitis mice. In colitis crypts, a notable cytokine-cytokine receptor, miR-494-3p-targeted EDA2R and the ligand EDA-A2, suppressed colonic stemness and epithelial repair by inhibiting ß-catenin/c-Myc. In differentiated IECs, miR-494-3p inhibits macrophage recruitment, M1 activation and EDA-A2 secretion by targeting IKKß/NF-κB in colitis. A miR-494-3p agomir system notably ameliorated the severity of colonic colitis in vivo. Collectively, our findings uncover a miR-494-3p-mediated cross-talk mechanism by which macrophage-induced intestinal stem cell impairment aggravates intestinal inflammation.

Research progress on antibiotic resistance of Escherichia coli O157:H7 / 预防医学

@#Contamination of foodborne pathogens is the main cause of related diseases. Escherichia coli O157:H7 (E.coli O157:H7), as a representative of pathogenic E.coli, is one of the most severe and commonly reported E.coli in the world, but there is still no effective clinical treatment against the infection. Antibiotics show effective in the early infection of E.coli O157:H7. However, their extensive use has led to drug-resistant bacteria and genes in recent years, which becomes a great threat to public health. This article reviews the research progress of E.coli O157:H7 from the prevalence of antibiotic-resistant bacteria, the resistance mechanism, and the prevention and control methods, in order to provide a reference for its prevention, early clinical treatment and related research.

Traditional Chinese medicine for the treatment of pulmonary fibrosis: A protocol for systematic review and meta-analysis of overview.

BACKGROUND: Since December 2019, there have been many cases of viral pneumonia of unknown causes in Wuhan City, Hubei Province. During the period of novel coronavirus, according to the observation of limited autopsy and biopsy pathological results, pulmonary interstitial fibrosis appeared in some pathological changes of lung. Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial pneumonia with unknown etiology and pathological changes limited to the lung. At present, there is still a lack of reevaluation of systematic evaluation of traditional Chinese medicine treatment IPF. Therefore, a systematic re-evaluation of the systematic evaluation of traditional Chinese medicine in the treatment of pulmonary fibrosis may help to understand the effective treatment scheme of traditional Chinese medicine in the treatment of pulmonary fibrosis and provide more reliable evidence for the first-line clinicians to treat novel coronavirus. METHODS: We will search 3 foreign electronic databases (Cochrane Library, Embase, PubMed) and 4 Chinese electronic databases (China National Knowledge Infrastructure [CNKI], WangFang Database, Chinese Biomedical Literature Database [CBM], and Chinese Scientific Journal Database [VIP]) to collect potential systematic reviews from their inceptions to February 2020. The language of publication is limited to Chinese or English. We will consider SRs and meta-analysis of Traditional Chinese Medicine for the Treatment of pulmonary fibrosis. Two reviewers will identify relevant studies, and then assess the methodological quality by assessment of multiple systematic reviews-2 tool. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) report checklist to assess the quality of reports included in the study. In order to better evaluate the systematic evaluation included in this research, risk of bias in systematic review tool is included in this research to evaluate the methodological quality. The quality of evidence of the included systematic reviews was assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The Primary outcomes include: Clinical total effective rate, curative effect of TCM symptoms, pulmonary function and blood gas analysis. RESULTS: The results of this study will be published in a peer-reviewed journal. CONCLUSIONS: We expect to obtain reliable evidence from systematic analysis of traditional Chinese medicine treatment of pulmonary fibrosis in an available and useful document. REGISTRATION NUMBER: INPLASY202060029.

Effects of salvianolic acid B on liver fibrosis: A protocol for systematic review and meta analysis.

BACKGROUND: Liver fibrosis is a pathological change existing in most chronic liver diseases, which leads to abnormal changes in liver tissue structure and affects the normal physiological function of liver. Without effectively control, liver fibrosis can develop into cirrhosis and increase the risk of liver cancer. Salvianolic acid B (Sal B) is the main active component in the water-soluble extract from Salvia miltiorrhiza, which is a traditional Chinese medicine usually used for treating cardiovascular and liver diseases. It is reported that Sal B shown a good action against liver fibrosis via numerous signaling pathways, which indicate that Sal B is a potential candidate drug for the treatment of liver fibrosis. METHODS: We searched the related researches from the following electronic databases: PubMed, EMBASE, Web of science, China National Knowledge Infrastructure (CNKI), China Biology Medicine (CBM), Wan fang Database for Chinese Technical Periodicals and VIP Database. All the databases were searched from inception to December 2019. No restriction of language, publication date, or publication status. PICO of this systematic review are shown as flowing: P, preclinical studies which evaluated the effects of Sal B on the animal models of liver fibrosis with controlled studies; I, received Sal B as only treat in any dose; C, received normal saline, distilled water, or no treatment; O, the primary outcome include measure will be the decrease in liver fibrosis score, and the secondary outcomes include the index of liver fibrosis. All the included data will be analyzed with the software of Review Manager 5.2 and STATA 14.2. DISCUSSION: The purpose of this study is to conduct a systematic review and meta-analysis to assess the effects on anti-liver fibrosis of Sal B, and this will be contribute to drug development and pathological mechanisms of clinical research. TRIAL REGISTRATION: INPLASY202050101, registered on 28/5/2020.

A comprehensive evaluation of association between homocysteine levels and single nucleotide polymorphisms with hypertension risk: A protocol of systematic review and network meta-analysis.

BACKGROUND: According to the relevant reports that single nucleotide polymorphisms (SNPs) may contribute to change of homocysteine (HCY) levels and increase the risk of hypertension (HTN). During the inconsistent results, this meta-analysis purpose is systematically review and synthesized relevant data on HCY levels and SNPs in HTN. METHODS: The systematic search database, from the following database to find out the association studies of SNPs and HTN publications up until March 2020 from the databases of PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), the Chinese Science and Technology Periodical Database (VIP) and Wan fang databases, and Chinese Biomedical Literature Database (CBM). Network meta-analysis and Thakkinstian's algorithm were used to select the most appropriate genetic model, along with false positive report probability (FPRP) for noteworthy associations. All statistical analyses were calculated with STATA software (version 14.0; StataCorp, College Station, TX). RESULTS: This meta-analysis will provide high-quality evidence to the effects of SNP on HTN and levels of HCY, and find between SNPs and HTN susceptibility on in all the genetic models, and choose the best one. CONCLUSIONS: This meta-analysis will research which SNP is the most correlated with HTN risk. REGISTRATION: INPLASY202050002.

Quercetin for myocardial ischemia reperfusion injury: A protocol for systematic review and meta-analysis.

BACKGROUND: At present, there is no effective therapy for preventing myocardial ischemia reperfusion injury (MIRI), and it is inevitable. The methods how to effectively decrease MIRI have attracted the attention of medical researches in recent years. Quercetin is a part of natural flavonoids in plant polyphenols. Many studies have found that quercetin has a positive effect on MIRI. METHODS: In order to clarify the effectiveness and potential mechanisms of quercetin for MIRI animals, we searched for animal studies of quercetin for MIRI in Wanfang data Information, Chinese National Knowledge Infrastructure, VIP information database, China Biology Medicine disc, EMBASE, PubMed, and Web of Science. Participant intervention comparator outcomes of this study are as flowing: P, rats in MIRI; I, received quercetin treatment merely; C, received only vehicle or no treatment; O, Main outcomes are myocardial infarction size and markers of myocardial injury. Additional outcomes are serum indices or protein levels tied to the mechanisms of quercetin in myocardial l/R injury. Review Manager 5.2 software and Stata14.0 will be used for data analysis. SYRCLE's risk of bias tool will be used for risk of bias analysis of animal studies. DISCUSSION: This preclinical systematic review and meta-analysis will evaluate the effects and mechanisms of quercetin for MIRI animals, and provide more evidence-based guidance for transforming basic research into clinical treatment. TRIAL REGISTRATION: INPLASY202050067, registered on 16/5/2020.

Author Correction: In vivo clonal expansion and phenotypes of hypocretin-specific CD4+ T cells in narcolepsy patients and controls.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

[Immunopathology and immunomodulatory roles of interleukin-12 in periodontal disease].

PURPOSE: To investigate the immunopathology and immunomodulatory roles of interleukin-12 (IL-12) in periodontal disease. METHODS: Ninety-eight patients with chronic periodontitis from January 2016 to January 2019 were enrolled and divided into mild group (30 cases), moderate group (35 cases) and severe group (33 cases) according to the severity of periodontitis; meanwhile, 30 healthy subjects who underwent periodontal examination in our hospital were selected as the control group. Clinical periodontal indicators including probing depth(PD), attachment loss(AL), plaque index(PLI), bleeding index(BI), Th cell expression (Th1, Th2, Th17) in peripheral blood, IL-12 levels in gingival crevicular fluid (GCF) and serum were measured. SPSS 20.0 software package was performed to analyze the correlation between IL-12 levels in GCF and serum and Th1, Th2, Th17, PD, AL, PLI, and BI. RESULTS: The differences of PD, PLI and BI among the groups were statistically significant(P<0.05). The levels of PD, PLI and BI in the mild, moderate and severe group were significantly higher than those in the control group (P<0.05). The difference of AL index among mild, moderate and severe group was statistically significant(P<0.05). The PD, AL, PLI, and BI in the moderate and severe group was significantly higher than those in the mild group(P<0.05), and the severe group was significantly higher than the mild group(P<0.05). Th1, Th2 and Th17 were significantly higher in the mild, moderate and severe group than in the control group(P<0.05); the moderate, severe group was significantly higher than the mild group in terms of Th1, Th2 and Th17 (P<0.05), and the severe group was significantly higher than the moderate group (P<0.05). The IL-12 levels in GCF and serum of the mild, moderate, and severe groups were significantly higher than those of the control group (P<0.05); IL-12 levels in the the moderate and severe groups were significantly higher than those in the mild group (P<0.05), and the IL-12 were significantly higher in the severe group than in the moderate group (P<0.05); IL-12 was positively correlated with PD, AL, PLI, BI, Th1, Th2 and Th17(P<0.05). H-E staining showed there were fewer lymphocytes in the mild group, more lymphocytes in the moderate group, and dense lymphocytes in the severe group with significant hemorrhage in intercellular mesenchyme. The IL-12 protein positive staining results were expressed in gingival tissue lymphocyte pulp with significant brown observed. The positive staining of IL-12 protein in the gingival tissues in the mild, moderate and severe group was significantly higher than in the control group, and the staining was aggravated with mild, moderate and severe inflammatory changes. CONCLUSIONS: IL-12 is involved in the immunoregulatory mechanism of periodontal disease and may be a key pro-inflammatory cytokine in the development of periodontitis.