Periodontitis is the leading cause of
tooth loss in adults, and psychological factors play an important role in the development of
periodontitis. To elucidate the adverse effects of psychological stress on the inflammatory process and redox status of
periodontitis tissue, fifty male Sprague-Dawley rats were divided into the control, experimental
periodontitis, psychological stress, experimental
periodontitis plus psychological stress, and experimental
periodontitis plus psychological stress plus
fluoxetine groups. Chronic unpredictable mild stress (CUMS) was used to establish psychological stress, and
silk ligature was used to induce experimental
periodontitis. Four weeks later, stressed rats showed altered behaviour, serum
hormone levels, and
sucrose preference. More obvious
alveolar bone loss and attachment loss and higher
protein expressions of inflammatory
cytokines were observed in the experimental
periodontitis plus psychological stress group. The combination of CUMS and
periodontitis had synergistic effects on increasing
hypoxia-inducible factor-1α (HIF-1α)
protein expression and
reactive oxygen species (ROS) and
malondialdehyde (MDA) contents and decreasing
antioxidant enzyme activities compared with those in the stress or
periodontitis groups. Moreover, psychological stress further increased p-IκBα and p-NF-κB p65
protein levels and decreased IκBα
protein levels in
periodontitis rats.
Fluoxetine administration alleviated the adverse effects of psychological stress on the progression of
periodontitis in rats. These results hint us that psychological stress could aggravate
inflammation in
periodontitis tissues, which may be partly due to local worsening of oxidative damage and further activation of the
nuclear factor kappa-B (NF-κB) signalling pathway.