Novel roles of an intragenic G-quadruplex in controlling microRNA expression and cardiac function.

Simultaneous dysregulation of multiple microRNAs (miRs) affects various pathological pathways related to cardiac failure. In addition to being potential cardiac disease-specific markers, miR-23b/27b/24-1 were reported to be responsible for conferring cardiac pathophysiological processes. In this study, we identified a conserved guanine-rich RNA motif within the miR-23b/27b/24-1 cluster that can form an RNA G-quadruplex (rG4) in vitro and in cells. Disruption of this intragenic rG4 significantly increased the production of all three miRs. Conversely, a G4-binding ligand tetrandrine (TET) stabilized the rG4 and suppressed miRs production in human and rodent cardiomyocytes. Our further study showed that the rG4 prevented Drosha-DGCR8 binding and processing of the pri-miR, suppressing the biogenesis of all three miRs. Moreover, CRISPR/Cas9-mediated G4 deletion in the rat genome aberrantly elevated all three miRs in the heart in vivo, leading to cardiac contractile dysfunction. Importantly, loss of the G4 resulted in reduced targets for the aforementioned miRs critical for normal heart function and defects in the L-type Ca2+ channel-ryanodine receptor (LCC-RyR) coupling in cardiomyocytes. Our results reveal a novel mechanism for G4-dependent regulation of miR biogenesis, which is essential for maintaining normal heart function.

Isosibiricin inhibits microglial activation by targeting the dopamine D1/D2 receptor-dependent NLRP3/caspase-1 inflammasome pathway.

Microglia-mediated neuroinflammation is a crucial risk factor for neurological disorders. Recently, dopamine receptors have been found to be involved in multiple immunopathological processes and considered as valuable therapeutic targets for inflammation-associated neurologic diseases. In this study we investigated the anti-neuroinflammation effect of isosibiricin, a natural coumarin compound isolated from medicinal plant Murraya exotica. We showed that isosibiricin (10-50 µM) dose-dependently inhibited lipopolysaccharide (LPS)-induced BV-2 microglia activation, evidenced by the decreased expression of inflammatory mediators, including nitrite oxide (NO), tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß) and interleukin-18 (IL-18). By using transcriptomics coupled with bioinformatics analysis, we revealed that isosibiricin treatment mainly affect dopamine receptor signalling pathway. We further demonstrated that isosibiricin upregulated the expression of dopamine D1/2 receptors in LPS-treated BV-2 cells, resulting in inhibitory effect on nucleotide binding domain-like receptor protein 3 (NLRP3)/caspase-1 inflammasome pathway. Treatment with dopamine D1/2 receptor antagonists SCH 23390 (1 µM) or sultopride (1 µM) could reverse the inhibitory effects of isosibiricin on NLRP3 expression as well as the cleavages of caspase-1 and IL-1ß. Collectively, this study demonstrates a promising therapeutic strategy for neuroinflammation by targeting dopamine D1/2 receptors.

Lactic acid induces lactate transport and glycolysis/OXPHOS interconversion in glioblastoma.

The Warburg effect is a dominant phenotype of most tumor cells. Recent reports have shown that the Warburg effect can be reprogrammed by the tumor microenvironment. Lactic acidosis and glucose deprivation are the common adverse microenvironments in solid tumor. The metabolic reprogramming induced by lactic acid and glucose deprivation remains to be elucidated in glioblastoma. Here, we show that, under glucose deprivation, lactic acid can preserve high ATP levels and resist cell death in U251 cells. At the same time, we find that MCT1 and MCT4 are significantly highly expressed. The metabolic regulation factor HIF-1α decreased and C-MYC increased. Nuclear respiratory factor 1 (NRF1) and oxidative phosphorylation (OXPHOS)-related proteins (NDUFB8, ND1) are all distinctly increased. Therefore, lactic acid can induce lactate transport and convert the dominant Warburg effect to OXPHOS. Through bioinformatics analysis, the high expression of HIF-1α, MCT1 or MCT4 indicate a poor prognosis in glioblastoma. In addition, in glioblastoma tissue, HIF-1α, MCT4 and LDH are highly expressed in the interior region, and their expression is decreased in the lateral region. MCT1 can not be detected in the interior region and is highly expressed in the lateral region. Hence, different regions of glioblastoma have diverse energy metabolic pathways. Glycolysis occurs mainly in the interior region and OXPHOS in the lateral region. In general, lactic acid can induce regional energy metabolic reprogramming and assist tumor cells to adapt and resist adverse microenvironments. This study provides new ideas for furthering understanding of the metabolic features of glioblastoma. It may promote the development of new therapeutic strategies in GBM.

[Noncoding RNA in the Regulation of Hepatic Glucose and Lipid Metabolism].

In the past decades, diabetes, in particular type 2 diabetes (T2D)mainly characterized by global insulin resistance and pancreatic beta cell failure, had become epidemic and a severe public health threat worldwide with the development of economy and change of lifestyle.The interactions between environment factors and genetic background play vital roles in the development and progression of T2D.More recently, it had been revealed that non-coding RNA including microRNA (miRNA)and long noncoding RNA (LncRNA)are widely involved inthe regulation of glucose and lipid metabolism. So far, it had been established that deregulated miRNA and LncRNA profile in main metabolic tissues is tightly associated with T2D,and intensive studies on non-coding RNAs had shed light on understanding the pathogen-esis of T2D.The current review aimed to briefly summarize and discuss the latest findings regarding the role and mechanism of miRNAs and LncRNAs in the regulation hepatic glucose and lipid metabolism.

The relationship between rational drug design and drug side effects.

Previous analysis of systems pharmacology has revealed a tendency of rational drug design in the pharmaceutical industry. The targets of new drugs tend to be close with the corresponding disease genes in the biological networks. However, it remains unclear whether the rational drug design introduces disadvantages, i.e. side effects. Therefore, it is important to dissect the relationship between rational drug design and drug side effects. Based on a recently released drug side effect database, SIDER, here we analyzed the relationship between drug side effects and the rational drug design. We revealed that the incidence drug side effect is significantly associated with the network distance of drug targets and diseases genes. Drugs with the distances of three or four have the smallest incidence of side effects, whereas drugs with the distances of more than four or smaller than three show significantly greater incidence of side effects. Furthermore, protein drugs and small molecule drugs show significant differences. Drugs hitting membrane targets and drugs hitting cytoplasm targets also show differences. Failure drugs because of severe side effects show smaller network distances than approved drugs. These results suggest that researchers should be prudent on rationalizing the drug design. Too small distances between drug targets and diseases genes may not always be advantageous for rational design for drug discovery.

[Advances in high-throughput transcriptome research of traditional Chinese medicines].

Traditional Chinese medicine is a treasure of Chinese culture, absorbing the wisdom of the Chinese people. Continuous application of new technologies makes traditional Chinese medicine research advance with the times. After several years of development, high-throughput transcriptome study has become a mature research tool in biology. This paper reviewed the advances in medicine transcriptome study, and compared two sequencing platforms, Roche's GS FLX platform and Illumina's HiSeq 2000 platform. Moreover, this paper introduced medicine transcriptome analysis process, with Panax quinquefolius and Lonicera japonica for examples, showing the characteristics of traditional Chinese medicine transcriptome studies. High-throughput transcriptome studies facilitate traditional Chinese medicine research with overall understand of functional genes, give clear elucidation of metabolic pathways, lay molecular foundation for the traditional Chinese medicine research and offer modern interpretation for traditional Chinese medicine theory. However, the current study faces several difficulties, including weak molecular basis, high sequencing cost and staff shortages in data anaysis. In the future, with the development in sequencing technology, the combination of transcriptome and other genomics, such as proteome and metabolome, will lay a solid foundation for the new high-throughput screening and developing model for the traditional Chinese medicine industry.

Progress in Traditional Chinese Medicine Against Respiratory Viruses: A Review.

Respiratory viruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV)-1, SARS-CoV-2, influenza A viruses, and respiratory syncytial virus, pose a serious threat to society. Based on the guiding principles of "holism" and "syndrome differentiation and treatment", traditional Chinese medicine (TCM) has unique advantages in the treatment of respiratory virus diseases owing to the synergistic effect of multiple components and targets, which prevents drug resistance from arising. According to TCM theory, there are two main strategies in antiviral treatments, namely "dispelling evil" and "fu zheng". Dispelling evil corresponds to the direct inhibition of virus growth and fu zheng corresponds to immune regulation, inflammation control, and tissue protection in the host. In this review, current progress in using TCMs against respiratory viruses is summarized according to modern biological theories. The prospects for developing TCMs against respiratory viruses is discussed to provide a reference for the research and development of innovative TCMs with multiple components, multiple targets, and low toxicity.

TGF­ß1­induced epithelial­mesenchymal transition increases fatty acid oxidation and OXPHOS activity via the p­AMPK pathway in breast cancer cells.

Breast cancer is the most common malignancy in women, and metastasis is the leading cause of death in breast cancer patients. Previous studies have shown that epithelial­mesenchymal transition (EMT) is involved in the metastasis of breast cancer, but the metabolic reprogramming and regulation mechanisms involved in the EMT process are still unclear. In the present study, we successfully constructed an EMT cell model induced by transforming growth factor ß1 (TGF­ß1) treatment of MCF­7 cells at different times. The results showed that cell adhesion decreased, cell invasion increased and ATP levels increased in EMT MCF­7 cells treated with TGF­ß1. Furthermore, the expression of fatty acid synthase (FASN) was decreased, and the expression of key fatty acid ß­oxidation enzymes (CPT1 and CD36) was elevated in treated cells compared to control cells. These results showed that the fatty acid oxidation pathway was enhanced. In addition, the expression of NADH:ubiquinone oxidoreductase subunit B8 (NDUFB8), mitochondrial transcription factor A (TFAM) and cytochrome c oxidase subunit I (COXI) increased, and the mitochondrial DNA copy number and ROS levels were also significantly increased during TGF­ß1­induced EMT. These results indicated that mitochondrial oxidative phosphorylation (OXPHOS) activity was enhanced during EMT. In addition, we observed that the expression of p­AMPK was increased and ACC (Acetyl­CoA Carboxylase) was decreased during TGF­ß1­induced EMT in MCF­7 cells. Immunohistochemical analysis of clinical samples revealed high expression of FASN in epithelial cells that had high expression of E­cadherin, while high expression of CPT­1 was observed in mesenchymal cells that had high expression of vimentin. Results of the current study showed a metabolic transition in TGF­ß1­induced EMT in MCF­7 cells. This transition may regulate fatty acid oxidation and OXPHOS activity in EMT MCF­7 cells through the p­AMPK pathway. These data suggest that a metabolic transition that suppresses lipogenesis and favors energy production is an essential component of TGF­ß1­induced EMT and metastasis in breast cancer. This study thus provides a new strategy for identifying new therapeutic targets for breast cancer.

High expression of the TEFM gene predicts poor prognosis in hepatocellular carcinoma.

BACKGROUND: Mitochondrial transcription elongation factor (TEFM) is an essential molecule that regulates the replication-transcription switch of mitochondrial DNA. TEFM modulates both transcription elongation and RNA processing in mitochondria. The purpose of the present study was to determine the association of TEFM with tumor progression and prognosis in hepatocellular carcinoma (HCC) patients. METHODS: The different protein expression level of TEFM among HCC cell lines was detected by Western blotting. The gene expression profiling interactive analysis (GEPIA) was used to dynamically analyze the mRNA expression of TEFM gene in different stages of HCC. The protein and mRNA expression levels of TEFM were detected by immunohistochemistry, Western blotting and qRT-PCR. The mRNA-SeqV2 expression of TEFM and clinical information of HCC patients were downloaded from the TCGA database by using R3.6.3 software. Next, the relationships between the expression level of TEFM and clinicopathological characteristics and the prognostic value of TEFM were analyzed. A Cox regression model was used for multivariate analysis of the factors that affected the prognosis of HCC. Finally, the association between the expression levels of TEFM and other mitochondrial regulatory genes and HCC biomarker genes was analyzed by GEPIA. RESULTS: TEFM is upregulated in HCC cell lines compared to noncancerous liver cell line. TEFM protein and mRNA expression levels in HCC tissues were significantly upregulated compared with those in noncancerous liver tissues. In addition, the mRNA expression level of TEFM was significantly correlated with sex, serum AFP level, and vascular invasion (P<0.05). Further analysis showed that high expression level of TEFM was unfavorable in terms of the prognosis of patients with HCC. Cox multivariate regression analysis showed that patient age, vascular invasion, and TEFM expression were independent factors affecting the prognosis of HCC patients (P<0.05). The expression level of the TEFM gene was significantly positively correlated with the expression of multiple mitochondrial regulatory genes and biomarker genes of HCC (P<0.01, R>0). CONCLUSIONS: Our findings reveal that TEFM may play an important role in the progression of HCC. More importantly, the elevated expression of TEFM may potentially predict poor overall survival (OS) and disease-free survival (DFS) in patients with HCC.

Identifying potential treatments of COVID-19 from Traditional Chinese Medicine (TCM) by using a data-driven approach.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese Medicine (TCM) has been widely used as an approach worldwide. Chinese Medicines (CMs) had been used to treat and prevent viral infection pneumonia diseases for thousands of years and had accumulated a large number of clinical experiences and effective prescriptions. AIM OF THE STUDY: This research aimed to systematically excavate the classical prescriptions of Chinese Medicine (CM), which have been used to prevent and treat Pestilence (Wenbing, Wenyi, Shiyi or Yibing) for long history in China, to obtain the potential prescriptions and ingredients to alternatively treat COVID-19. MATERIALS AND METHODS: We developed the screening system based on data mining, molecular docking and network pharmacology. Data mining and association network were used to mine the high-frequency herbs and formulas from ancient prescriptions. Virtual screening for the effective components of high frequency CMs and compatibility Chinese Medicine was explored by a molecular docking approach. Furthermore, network pharmacology method was used to preliminarily uncover the molecule mechanism. RESULTS: 574 prescriptions were obtained from 96,606 classical prescriptions with the key words to treat "Warm diseases (Wenbing)", "Pestilence (Wenyi or Yibing)" or "Epidemic diseases (Shiyi)". Meanwhile, 40 kinds of CMs, 36 CMs-pairs, 6 triple-CMs-groups existed with high frequency among the 574 prescriptions. Additionally, the key targets of SARS-COV-2, namely 3CL hydrolase (Mpro) and angiotensin-converting enzyme 2(ACE2), were used to dock the main ingredients from the 40 kinds by the LigandFitDock method. A total of 66 compounds components with higher frequency were docked with the COVID-19 targets, which were distributed in 26 kinds of CMs, among which Gancao (Glycyrrhizae Radix Et Rhizoma), HuangQin (Scutellariae Radix), Dahuang (Rhei Radix Et Rhizome) and Chaihu (Bupleuri Radix) contain more potential compounds. Network pharmacology results showed that Gancao (Glycyrrhizae Radix Et Rhizoma) and HuangQin (Scutellariae Radix) CMs-pairs could also interact with the targets involving in immune and inflammation diseases. CONCLUSIONS: These results we obtained probably provided potential candidate CMs formulas or active ingredients to overcome COVID-19. Prospectively, animal experiment and rigorous clinic studies are needed to confirm the potential preventive and treat effect of these CMs and compounds.

[Prediction of the microRNAs related to cardiovascular diseases by bioinformatics].

OBJECTIVE: To predict the microRNAs (miRNAs) related to cardiovascular diseases. METHODS: Bioinformatics was used to find all cardiovascular disease related and cardiovascular function related protein-coding genes, and miRNAs were identified that localized the same transcription units as the above genes. Then other cardiovascular disease related miRNAs were identified by an miRNAs set and family analysis and Gene Ontology(GO). RESULTS: Twenty potential cardiovascular disease related miRNAs were predicted from 626 cardiovascular disease related miRNAs, five of which had been confirmed by experiments. CONCLUSION: This study is of great help for the diagnosis and research of cardiovascular diseases, but the final conclusion need to be confirmed by experiments.

Exploration of the mechanisms of Ge Gen Decoction against influenza A virus infection.

Ge Gen Decoction (GGD), a Traditional Chinese Medicine prescription, is mainly used to treat infectious respiratory diseases and can relieve the symptoms of influenza A virus (IAV) infection. However, the underlying mechanism of GGD against IAV infection remains unclear. In this study, we found that GGD had moderate anti-IAV activity in vitro. GGD was more effective when given before the viral infection and targeted the viral attachment and replication stages rather than the internalization stage. In vivo, GGD treatment reduced thevirus titers of lung tissue significantly and improved the survival rate, lung index, and pulmonary histopathological changes in H1N1-infected mice. We observed the changes in several key immuno-related indexes in GGD administrated H1N1-infected mice with anti-IAV drug oseltamivir phosphate as the control. GGD treatment decreased the expression of TNF-α and improved Th1/Th2 immune balance to reduce the excessive immune response in H1N1-infected mice. Besides, the expression of the toll-like receptor 7 signaling pathway in H1N1-infected mice decreased after GGD treatment. Our results showed that GGD has anti-IAV activity and can modulate the immune system to relieve lung inflammation.

Diversity of O-Glycosyltransferases Contributes to the Biosynthesis of Flavonoid and Triterpenoid Glycosides in Glycyrrhiza uralensis.

Licorice (Glycyrrhiza uralensis) is a popular medicinal plant containing more than 70 flavonoid and triterpenoid glycosides. Thus far, only a few reports are available on the glycosylation enzymes involved in their biosynthesis. In this work, we mined the transcriptome data of G. uralensis and discovered 43 candidate genes for O-glycosyltransferase (O-GT). Among them, 17 genes could be expressed in E. coli, and functions of the enzymes were analyzed by catalyzing eight native substrates. As a result, we characterized 11 O-GTs, including isoflavone 7-O-GTs, flavonol 3-O-GTs, and promiscuous O-GTs catalyzing flavones, chalcones, and triterpenoids. They could efficiently synthesize key licorice compounds such as liquiritin, isoliquiritin, ononin, and 3-O-ß-d-glucuronosyl glycyrrhetinic acid. The diversity of O-GTs contributes to the biosynthesis of various glycosides in licorice. These enzymes could also be used as biocatalytic tools to synthesize other bioactive O-glycosides.

Gut microbiota analysis and its significance in vasovagal syncope in children.

BACKGROUND: Vasovagal syncope (VVS) is common in children and greatly affect both physical and mental health. But the mechanisms have not been completely explained. This study was designed to analyze the gut microbiota in children with VVS and explore its clinical significance. METHODS: Fecal samples from 20 VVS children and 20 matched controls were collected, and the microbiota were analyzed by 16S rRNA gene sequencing. The diversity and microbiota compositions of the VVS cases and controls were compared with the independent sample t test or Mann-Whitney U test. The correlation between the predominant bacteria and clinical symptoms was analyzed using Pearson or Spearman correlation test. RESULTS: No significant differences in diversity were evident between VVS and controls (P > 0.05). At the family level, the relative abundance of Ruminococcaceae was significantly higher in VVS children than in controls (median [Q1, Q3]: 22.10% [16.89%, 27.36%] vs. 13.92% [10.31%, 20.18%], Z = -2.40, P < 0.05), and LEfSe analysis revealed Ruminococcaceae as a discriminative feature (linear discriminant analysis [LDA] score > 4, P < 0.05). The relative abundance of Ruminococcaceae in VVS patients was positively correlated with the frequency of syncope (r = 0.616, P < 0.01). In terms of its correlation with hemodynamics, we showed that relative abundance of Ruminococcaceae was negatively correlated with the systolic and diastolic pressure reduction at the positive response in head-up tilt test (HUTT; r = -0.489 and -0.448, all P < 0.05), but was positively correlated with the mean pressure drop and decline rate (r = 0.489 and 0.467, all P < 0.05) as well as diastolic pressure drop and decline rate at the HUTT positive response (r = 0.579 and 0.589, all P < 0.01) in VVS patients. CONCLUSION: Ruminococcaceae was the predominant gut bacteria and was associated with the clinical symptoms and hemodynamics of VVS, suggesting that gut microbiota might be involved in the development of VVS.

Association between Nonalcoholic Fatty Liver Disease and Carotid Artery Disease in a Community-Based Chinese Population: A Cross-Sectional Study.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases with a high prevalence in the general population. The association between NAFLD and cardiovascular disease has been well addressed in previous studies. However, whether NAFLD is associated with carotid artery disease in a community-based Chinese population remained unclear. The aim of this study was to investigate the association between NAFLD and carotid artery disease. METHODS: A total of 2612 participants (1091 men and 1521 women) aged 40 years and older from Jidong of Tangshan city (China) were selected for this study. NAFLD was diagnosed by abdominal ultrasonography. The presence of carotid stenosis or plaque was evaluated by carotid artery ultrasonography. Logistic regression was used to analyze the association between NAFLD and carotid artery disease. RESULTS: Participants with NAFLD have a higher prevalence of carotid stenosis (12.9% vs. 4.6%) and carotid plaque (21.9% vs. 15.0%) than those without NAFLD. After adjusting for age, gender, smoking status, income, physical activity, diabetes, hypertension, triglyceride, waist-hip ratio, and high-density lipoprotein, NAFLD is significantly associated with carotid stenosis (odds ratio [OR]: 2.06, 95% confidence interval [CI]: 1.45-2.91), but the association between NAFLD and carotid plaque is not statistically significant (OR: 1.10, 95% CI: 0.8-1.40). CONCLUSION: A significant association between NAFLD and carotid stenosis is found in a Chinese population.

Diverse endometrial mRNA signatures during the window of implantation in patients with repeated implantation failure.

High endometrial receptivity in the window of implantation (WOI) is essential for successful implantation. However, a diagnostic tool with high specificity for impaired endometrial receptivity remains to be developed. We collected endometrium specimens during the WOI from patients with RIF and women who conceived after one IVF/ICSI attempt. We conducted mRNA microarray on the samples followed by relevant comparative and functional analysis. Microarray analysis revealed 357 dysregulated mRNAs between the two groups. The majority of these mRNAs were found to encode membrane proteins by Gene Ontology (GO) analysis. The major functional biological pathways associated with the down-regulated mRNAs were cytokine-cytokine receptor interaction, the p53 signalling pathway and the complement and coagulation cascades. Up-regulated mRNAs were found mainly to participate in pathways such as PPAR signalling, hematopoietic cell lineage, phosphatidylinositol signalling system, ECM-receptor interaction and notch signalling. AQP3, DPP4 and TIMP3 whose expression patterns were down-regulated in RIF patients both by microarray and real-time PCR had a high correspondence with previous studies demonstrating that these genes may contribute to the defects in endometrial receptivity in RIF patients. Overall, these RIF-associated mRNAs may help devise new diagnostic tools for endometrial receptivity.

Maternal gene Ooep may participate in homologous recombination-mediated DNA double-strand break repair in mouse oocytes.

DNA damage in oocytes can cause infertility and birth defects. DNA double-strand breaks (DSBs) are highly deleterious and can substantially impair genome integrity. Homologous recombination (HR)-mediated DNA DSB repair plays dominant roles in safeguarding oocyte quantity and quality. However, little is known regarding the key players of the HR repair pathway in oocytes. Here, we identified oocyte-specific gene Ooep as a novel key component of the HR repair pathway in mouse oocytes. OOEP was required for efficient ataxia telangiectasia mutated (ATM) kinase activation and Rad51 recombinase(RAD51)focal accumulation at DNA DSBs. Ooep null oocytes were defective in DNA DSB repair and prone to apoptosis upon exogenous DNA damage insults. Moreover, Ooep null oocytes exhibited delayed meiotic maturation. Therefore, OOEP played roles in preserving oocyte quantity and quality by maintaining genome stability. Ooep expression decreased with the advance of maternal age, suggesting its involvement in maternal aging.

[Effect of fluoride on expression of telomerase reverse transcriptase expression and proliferating cell nuclear antigen in germ cells of rats' testes].

OBJECTIVE: To study the damages of fluoride on the male reproductive system in rat testes. METHODS: A total of 30 male SD rats were randomly divided into control group, high, low dose fluorine treated groups, which were given normal saline ,20 mg/kg sodium fluoride, and 10mg/kg sodium fluoride respectively. After 39 days the change of the weight of rats and the number of sperms were observed. The change of telomerase reverse transcriptase(TERT) and proliferating cell nuclear antigen (PCNA) were observed by using in situ hybridization and radioimmunoassay respectively. RESULTS: The weight was (273.39 +/- 20.68), (240.00 +/- 21.39) g in NaF treated groups, which was lower than that in control group(P < 0.05); The rate of TERT expression in germ cells of testes in NaF treated groups was (13.89 +/- 4.86)% and (6.33 +/- 4.42)% respectively, which was significantly lower than that in control group (P < 0.05). The rate of PCNA expression in germ cells of tests in NaF treated groups was (0.71 +/- 0.05)%, (0.60 +/- 0.08)% respectively, which also was significant lower than that in control group(P < 0.05). The number of sperms was (18.31 +/- 1.20)10(10)/L, (9.17 +/- 1.38)10(10)/L, which was lower than that in control group (P < 0.05). CONCLUSION: Fluorine possibly damages the male reproductive system by reducing the expression of TERT and PCNA.