title: A Rat Experimental Study of the Relationship Between Fluoride Exposure and Sensitive Biomarkers.
abstract: Chronic excessive fluoride exposure impairs human health and damages not only the skeletal system and the teeth but also the soft tissues such as the brain, liver, kidneys, pancreas and spinal cord. However, there is limited research regarding the exposure levels and sensitive biomarkers. This study was aimed to establish the relationship between fluoride exposure and sensitive biomarkers. Ninety-six rats were randomly divided into six groups, with each group exposed to 0, 2, 4, 8, 16 and 32 mg NaF/(kg.bw), respectively. Correlation analysis of the exposure levels, the tissue distributions and the effects was done, and the possible mathematical relationship between the exposure and sensitive biomarkers is discussed. Our findings revealed that the level of serum fluoride can serve as one of the sensitive indicators to reflect the ex-exposure levels (in the present article, ex-exposure means the fluoride exposure pathway from the outside, which differs from the burden of the organism). Furthermore, an equation determining the external exposure dose of serum fluoride was obtained by fitting the coefficient 0.901. Simultaneously, enzyme levels were closely compared with the burden of the tissue, which showed that the activities of alkaline phosphatase significantly correlated with serum fluoride levels (R2= -0.259, p < 0.05), as well as with the fluoride levels of the lung (R2= 0.463, ρ < 0.01), the thymus (R2= 0.429, ρ < 0.05) and the ovary/testicle (R2= 0.685, ρ < 0.01). Results suggested that excessive fluoride exposure might affect reproduction by altering the activities of alkaline phosphatase. In addition, some indicators related to immunity and calcium absorption exhibited sensitivity to tissue burden, among which activating transcriptional factor 4 (ATF4), an important indicator involved in bone metabolism, was found sensitive to the ex-exposure level. These findings highlight the gap between health effects in epidemiology research and the total intake amount of fluoride from the environment. This study presents a novel insight into the method of establishing the relationship between fluoride exposure and sensitive biomarkers.
authors.affiliation: Environment and Health Department, Chinese Research Academy of Environmental Sciences, Chaoyang District, Beijing, 100012, China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Environment and Health Department, Chinese Research Academy of Environmental Sciences, Chaoyang District, Beijing, 100012, China. wanghmxj@163.com.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wang
authors.affiliation: Environment and Health Department, Chinese Research Academy of Environmental Sciences, Chaoyang District, Beijing, 100012, China.
authors.forename: Binghui
authors.initials: B
authors.lastname: Zheng
authors.affiliation: Environment and Health Department, Chinese Research Academy of Environmental Sciences, Chaoyang District, Beijing, 100012, China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Han
authors.affiliation: Environment Standard Institute, Chinese Research Academy of Environmental Sciences, Chaoyang District, Beijing, 100012, China.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Chen
authors.affiliation: School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
mesh_terms: D051701:Activating Transcription Factor 4 / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D015415:Biomarkers / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005459:Fluorides / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000633:toxicity*; D008297:Male; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
chemical_list: C497110:Atf4 protein, rat; D015415:Biomarkers; D051701:Activating Transcription Factor 4; D000469:Alkaline Phosphatase; D005459:Fluorides
keywords: Enzyme levels; Sensitive biomarkers; Sodium fluoride (NaF); Tissue levels