Fluorosilicic acid induces DNA damage and oxidative stress in bone marrow mesenchymal stem cells

Correlation between dental fluorosis risk and bone-specific alkaline phosphatase, osteocalcin, matrix metalloproteinase and parathyroid hormone in children

Background

The aim of this study was to investigate the association between dental fluorosis occurrence in children and bone metabolism-related indicators, including bone-specific alkaline phosphatase (BALP), osteocalcin (OC), matrix metalloproteinase (MMP-2, MMP-9, MMP-20), and parathyroid hormone (PTH).

Methods

A total of 189 cases of school-age children who underwent health examinations in our hospital were enrolled, according to the presence or absence of dental fluorosis. They were divided into the fluorosis group (n=97) and fluoride-free group (n=92), and the serum BALP, OC, MMP-2, MMP-9, MMP-20, and PTH levels of the two groups were compared and relevant clinical data were collected. This study employed multivariate logistic regression to examine the factors associated with the development of dental fluorosis in children.

Results

The urine fluoride levels, BALP, MMP-2, and MMP9 of the children in the fluorosis group were higher than fluoride-free group, and the mother's educational level, per capita annual household income, OC, and PTH were lower than fluoride-free group (P<0.05). Based on Spearman correlation analysis, a positive correlation was identified between the urinary fluoride level, the extent of dental fluorosis, and indicators such as BALP, MMP-2, and MMP-9. (r=0.618, 0.558, 0.567, 0.597, 0.602, 0.571, P<0.001), and negatively correlated with OC and PTH (r=-0.580, -0.603, -0.549, -0.515, P<0.001). As the urinary fluoride level and the extent of dental fluorosis increased, there was a gradual elevation in serum BALP, MMP-2, and MMP-9 levels in children, while OC and PTH levels gradually decreased (P<0.05). After adjusting for confounding factors, including urinary fluoride, maternal education level, and per capita annual household income, multivariate Logistic regression analysis showed that BALP, OC, MMP-2, MMP-9, and PTH were independently associated with the risk of dental fluorosis (P<0.05).

Conclusions

High BALP, MMP-2, MMP-9, low OC, and PTH are independent factors affecting the occurrence of dental fluorosis and are related to the extent of dental fluorosis.

Progress in research on the role of fluoride in immune damage

Excessive fluoride intake from residential environments may affect multiple tissues and organs; however, the specific pathogenic mechanisms are unclear. Researchers have recently focused on the damaging effects of fluoride on the immune system. Damage to immune function seriously affects the quality of life of fluoride-exposed populations and increases the incidence of infections and malignant tumors. Probing the mechanism of damage to immune function caused by fluoride helps identify effective drugs and methods to prevent and treat fluorosis and improve people's living standards in fluorosis-affected areas. Here, the recent literature on the effects of fluoride on the immune system is reviewed, and research on fluoride damage to the immune system is summarized in terms of three perspectives: immune organs, immune cells, and immune-active substances. We reviewed that excessive fluoride can damage immune organs, lead to immune cells dysfunction and interfere with the expression of immune-active substances. This review aimed to provide a potential direction for future fluorosis research from the perspective of fluoride-induced immune function impairment. In order to seek the key regulatory indicators of fluoride on immune homeostasis in the future.

Measuring DNA modifications with the comet assay: a compendium of protocols

The comet assay is a versatile method to detect nuclear DNA damage in individual eukaryotic cells, from yeast to human. The types of damage detected encompass DNA strand breaks and alkali-labile sites (e.g., apurinic/apyrimidinic sites), alkylated and oxidized nucleobases, DNA-DNA crosslinks, UV-induced cyclobutane pyrimidine dimers and some chemically induced DNA adducts. Depending on the specimen type, there are important modifications to the comet assay protocol to avoid the formation of additional DNA damage during the processing of samples and to ensure sufficient sensitivity to detect differences in damage levels between sample groups. Various applications of the comet assay have been validated by research groups in academia, industry and regulatory agencies, and its strengths are highlighted by the adoption of the comet assay as an in vivo test for genotoxicity in animal organs by the Organisation for Economic Co-operation and Development. The present document includes a series of consensus protocols that describe the application of the comet assay to a wide variety of cell types, species and types of DNA damage, thereby demonstrating its versatility.

Biphasic Functions of Sodium Fluoride (NaF) in Soft and in Hard Periodontal Tissues

Sodium fluoride (NaF) is widely used in clinical dentistry. However, the administration of high or low concentrations of NaF has various functions in different tissues. Understanding the mechanisms of the different effects of NaF will help to optimize its use in clinical applications. Studies of NaF and epithelial cells, osteoblasts, osteoclasts, and periodontal cells have suggested the significant roles of fluoride treatment. In this review, we summarize recent studies on the biphasic functions of NaF that are related to both soft and hard periodontal tissues, multiple diseases, and clinical dentistry.