Mitochondria-Mediated Pathway Regulates C2C12 Cell Apoptosis Induced by Fluoride

Area of Science:

• Cell Biology
• Toxicology
• Biochemistry

Background:

• Fluoride is a common environmental ion, and excessive exposure can lead to toxicity.
• Skeletal muscle cells are susceptible to environmental insults.
• Apoptosis, or programmed cell death, is a critical cellular process regulated by various pathways.

Purpose of the Study:

• To investigate the mechanisms by which excessive fluoride induces apoptosis in skeletal muscle cells (C2C12 cells).
• To elucidate the role of the mitochondria-mediated pathway in fluoride-induced apoptosis.

Main Methods:

• C2C12 cells were exposed to varying concentrations of fluoride (0, 1, and 2.5 mmol/L) for 48 hours.
• Cell morphology and ultrastructure were examined using light microscopy and transmission electron microscopy (TEM).
• The expression levels of apoptosis-related proteins (Bax, Bcl-2, cytochrome c, caspase-3, caspase-9) were quantified using real-time PCR and immunocytofluorescence.

Main Results:

• Fluoride exposure at 1 and 2.5 mmol/L caused significant damage to C2C12 cell morphology and ultrastructure, including mitochondrial swelling and nuclear membrane loss.
• Expression of pro-apoptotic factors Bax, cytochrome c, caspase-3, and caspase-9 increased, while Bcl-2 expression was also upregulated.
• Fluoride damaged mitochondrial ultrastructure, leading to cytochrome c release into the cytoplasm.

Conclusions:

• Excessive fluoride induces apoptosis in C2C12 skeletal muscle cells.
• The primary mechanism involves damage to mitochondrial ultrastructure, subsequent cytochrome c release, and activation of the caspase cascade.
• This highlights the critical role of the mitochondria-mediated pathway in fluoride toxicity to skeletal muscle.