Fluoride Exposure Modulates Skeletal Development and Mineralization in Zebrafish Larvae

Area of Science:

• Developmental Biology
• Toxicology
• Biochemistry

Background:

• High fluoride levels in groundwater pose a global health concern, potentially leading to fluorosis and toxicity.
• While fluoride is essential, excessive intake disrupts hard tissue formation, affecting bone metabolism and mineral homeostasis.
• The impact of fluoride on early osteogenesis remains incompletely understood.

Purpose of the Study:

• To investigate the effects of fluoride exposure on osteogenic differentiation, bone development, and mineralization in zebrafish.
• To elucidate the dose-dependent impact of fluoride on skeletal development and related gene expression.

Main Methods:

• Zebrafish embryos were exposed to low (25 ppm NaF) and moderately high (50 ppm NaF) fluoride doses until 7 days postfertilization.
• Fluoride content, mineralization (Alizarin Red, ALP staining), cartilage morphology (Alcian blue), and gene expression of bone/cartilage markers were analyzed.
• Biochemical assays for alkaline phosphatase activity and hydroxyproline content were performed.

Main Results:

• Fluoride exposure led to a dose-dependent increase in larval fluoride content.
• Enhanced mineralization and alkaline phosphatase activity were observed in fluoride-exposed groups.
• Altered pharyngeal cartilage morphology and differential gene expression of osteogenic markers were noted, with low-dose enhancement and high-dose disruption.

Conclusions:

• Fluoride exposure significantly impacts osteogenic differentiation, bone development, and mineralization in zebrafish larvae.
• Low fluoride doses may enhance certain bone formation markers, while higher doses induce toxicity, affecting cartilage and bone metabolism.
• Zebrafish serve as a valuable model for understanding fluoride's complex effects on skeletal development.