To investigate the effects of apoptotic bodies (ABs) derived from dental pulp stem cells (DPSCs) on macrophage polarization and inflammation response in vivo.

Human DPSCs were extracted, cultured and identified. Staurosporine was used to apoptosis induction and differential methods were performed for ABs identification. The in vitro cultured macrophages were divided into 3 groups: solvent control, lipopolysaccharide (LPS), and the LPS+ABs. The macrophages were stimulated with LPS to induce inflammation followed by ABs treatment. In the untreated group, macrophages were added with an equal amount of solvent. The specific uptake of ABs by macrophages, the expression level of CD206 and the levels of inflammatory cytokines were analyzed. The mouse models of cutaneous wounds and dextran sulfate sodium (DSS)-induced colitis were established, and the mice were randomly divided into 3 groups: the PBS-treated group, the DPSCs-treated group, and the ABs-treated group. The mice were injected with the same volume of PBS, DPSCs and ABs, respectively. The body weight, histological pathology, the expression levels of CD206 and cytokines, and the extent of tissue regeneration were measured.

DPSCs and ABs derived from DPSCs were successfully isolated and characterized. ABs could be taken up by macrophage. While lipopolysaccharide(LPS) induced production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), ABs significantly reduced the levels of these pro-inflammatory cytokines and increased the expression of transforming growth factor-β (TGF-β) and CD206 (P < 0.01). In the cutaneous inflammatory wound model, the wound closure rate in mice intravenously injected with ABs was significantly accelerated (P < 0.05). The administration of ABs markedly reduced the pro-inflammatory factors levels and increased the CD206⁺ cell number. In the colitis model, treatment with ABs markedly reduced the loss in bodyweight (P < 0.05), recovered the colon length (P < 0.01), and significantly increased the CD206⁺ cell number.

DPSCs-derived ABs could enhance macrophage M2 polarization and attenuate inflammation. Therefore, ABs could be used as a promising cell replacement for inflammatory regulation and tissue regeneration.

To investigate the effect of root canal therapy (RCT) on inflammatory cytokines level in peripheral blood, anxiety, and depression in patients with pulpitis.

A total of 155 patients with pulpitis admitted to the Stomatology Hospital of the Fourth Military Medical University from June 2021 to June 2022 were treated with root canal therapy. Another 155 persons who received health examinations during the same period were selected as the control group. The Generalized Anxiety Disorder-7 (GAD-7) scores and the Patient Health Questionnaire-9 (PHQ-9)scores of the two groups were compared. The GAD-7, PHQ-9 and pain scores of the test group before treatment and 3 and 6 weeks after treatment were compared. Pain was assessed with a visual analog scale (VAS). Inflammatory cytokine[interleukin-8 (IL-8), interleukin-1 β (IL-1β), tumor necrosis factor-α (TNF-α), c-reactive protein (CRP)] levels in the test group before treatment and 3 and 6 weeks after treatment were compared.

The GAD-7 and PHQ-9 scores in the test group were higher than those in the control group before treatment (P ＜ 0.05). The GAD-7 and PHQ-9 scores in the test group at 3 and 6 weeks after treatment were lower than those before treatment (P ＜ 0.05); there was no significant difference between the GAD-7 and PHQ-9 scores at 3 and 6 weeks after treatment(P ＞ 0.05). The pain scores of the experimental group at 3 and 6 weeks after treatment were lower than those before treatment (P ＜ 0.05), and the pain scores 6 weeks after treatment were lower than those at 3 weeks after treatment (P ＜ 0.05). The levels of IL-8, IL-1β, TNF-α and CRP in the peripheral blood of the experimental group were lower 3 and 6 weeks after treatment than before (P ＜ 0.05), and the levels of IL-8 and IL-1β in the peripheral blood at 6 weeks after treatment were significantly lower than at 3 weeks after treatment (P ＜ 0.05). The levels of TNF-α and CRP in the peripheral blood at 6 weeks after treatment were not significantly different from those at 3 weeks after treatment (P ＞ 0.05).

The peripheral blood of patients with pulpitis has a high level of inflammatory cytokines, and the patients suffer from obvious anxiety and depression. Root canal therapy can relieve their anxiety and depression by reducing their level of inflammatory cytokines in peripheral blood.