Denervation-induced changes in cell proliferation in the rat molar after wounding

Area of Science:

• Dentistry
• Neuroscience
• Regenerative Medicine

Background:

• The dental pulp possesses intrinsic repair capabilities following traumatic injury.
• Understanding the neural regulation of pulpal healing is crucial for effective regenerative strategies.

Purpose of the Study:

• To quantitatively assess the peripheral nervous system's influence on pulpal cell proliferation after wounding.
• To elucidate the specific roles of key nerves in the dental pulp's response to injury.

Main Methods:

• Rats underwent various unilateral nerve resections: superior cervical ganglionectomy (SCG), inferior alveolar nerve (IAN) resection, chorda tympani (CT) resection, or combinations.
• A standardized wound was created by removing enamel and dentin from the mandibular molar.
• 3H-thymidine incorporation was measured at multiple time points (0-15 days) to assess cell proliferation.

Main Results:

• Innervation-intact controls showed a peak in cell proliferation 5 days post-wounding.
• Nerve resections generally increased initial cell labeling but suppressed the 5-day peak, delaying the proliferative response.
• Combined SCG and IAN resection resulted in the lowest labeled cell counts throughout, except at initial and termination points.

Conclusions:

• The peripheral nervous system significantly modulates pulpal cell proliferation and the timing of the repair response to wounding.
• Specific nerve pathways, particularly the SCG and IAN, play critical roles in regulating pulp healing dynamics.