CTGF and apoptosis in mouse osteocytes induced by tooth movement

Area of Science:

• Orthodontics
• Cell Biology
• Bone Remodeling

Background:

• Experimental tooth movement in rats is known to increase connective tissue growth factor (CTGF) gene expression.
• This process also induces apoptosis (programmed cell death) in osteocytes, the cells within bone tissue.

Purpose of the Study:

• To investigate the relationship between CTGF expression and osteocyte apoptosis during experimental tooth movement.
• To determine the role of these events in initiating bone remodeling.

Main Methods:

• CTGF mRNA expression was measured in osteocytes on the pressure side of the jaw.
• Osteocyte apoptosis was assessed following mechanical stimulation.
• Changes in osteocyte lacunae and osteoclast numbers were quantified over time.
• The rate of tooth movement was monitored.

Main Results:

• CTGF mRNA expression was detected in osteocytes within 2 hours of tooth movement initiation.
• Osteocyte apoptosis followed at 6 hours.
• An increase in empty osteocyte lacunae was observed by day 1.
• Osteoclast numbers significantly increased on the pressure side by day 3.
• Rapid tooth movement occurred by day 10.

Conclusions:

• CTGF expression and subsequent osteocyte apoptosis are early cellular responses to mechanical stimulation during tooth movement.
• These events are suggested to play a significant role in triggering the bone remodeling necessary for orthodontic tooth movement.