The Effects of TCDD on the Development of Teeth and Cortical Bone in Rats: Implications for Risk Assessment
Year: 2006
Type: article
Abstract: 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is certainly one the most extensively studied compounds in the world.The huge interest in this compound is explained by the fact that it is the most potent man-made chemical, and it is often used as a model compound for a group of chemicals (polychlorinated dibenzo-p-dioxins and furans, (PCDD/Fs) also known as "dioxins" and polychlorinated biphenyls (PCBs)) that share similar physicochemical and toxicological properties, though with lesser degrees of potency.Dioxins have spread all over the face of the earth and, due to their stability and lipophilicity, they have accumulated in food chains.Humans are exposed to PCDD/Fs and PCBs continuously via the diet; and in Scandinavia, the main source is fatty Baltic fish.European Commission has given Finland and Sweden a temporary exemption to use Baltic fish, and this matter will be revisited again in 2006.TCDD is able to elicit a wide variety of harmful effects in laboratory animals.These effects are mainly mediated via the aryl hydrocarbon receptor (AHR).Even though cancer has traditionally been used in the risk assessment, new data have revealed that developmental defects, such as alterations in reproductive organ development, are more sensitive to TCDD than cancer and of great importance.The present study describes new developmental defects induced by TCDD: alterations in tooth and bone development.Using three differentially sensitive rat lines it was demonstrated that the development of rodent dentition is disturbed at very low doses that are relevant for risk assessment, and that there are no major differences in sensitivity among lines.Changes in cortical bone development were also found, but only in the most sensitive rat line and only at the highest maternal dose level.As molar tooth cannot be remodeled, developmental defects in dentition are permanent.Previous studies have shown that also humans respond to PCDD/F exposure with altered dental development.Due to the extreme sensitivity of dentition to TCDD, alterations in dental development, such as deviations in enamel structure in humans, could be considered as a sensitive, though not necessarily an exclusive, indicator for dioxin exposure during early life.
Author: Hanna Miettinen
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2139992564