Depressive behavior induced by unpredictable chronic mild stress increases dentin hypersensitivity in rats

Area of Science:

• Neuroscience
• Oral Biology
• Stress Research

Background:

• Dental hypersensitivity is a common clinical condition.
• Unpredictable chronic mild stress (UCMS) is a model for depression.
• The link between stress, dental erosion, and pain perception is not fully understood.

Purpose of the Study:

• To investigate the effect of UCMS-induced depression on dentin hypersensitivity following dental erosion in rats.
• To explore the neurobiological correlates of this interaction, including stress hormones and brain glial responses.

Main Methods:

• Adult male rats were exposed to UCMS or not, and received either an acidic solution or water to induce dental erosion.
• Depressive-like behaviors, dentin hypersensitivity, plasma corticosterone and TNF-α levels, and astrocytic GFAP expression in specific brain regions were assessed.

Main Results:

• Dental erosion potentiated dentin hypersensitivity and increased corticosterone levels in stressed rats.
• Stressed rats showed increased astrocytic GFAP expression in the hypothalamus and prefrontal cortex, but decreased expression in the hippocampus.
• Tumor necrosis factor-alpha (TNF-α) levels increased only in non-stressed, eroded rats.

Conclusions:

• UCMS exacerbates the nociceptive response of dentin hypersensitivity, associated with elevated corticosterone.
• UCMS-induced changes in hypothalamic and prefrontal cortex astrogliosis may be linked to increased corticosterone.
• Reduced hippocampal astrocytic GFAP expression in stressed, eroded rats supports a connection between dentin hypersensitivity and depression.