Epigallocatechin-3-gallate inhibits proliferation and induces apoptosis in odontogenic keratocyst keratinocytes.

OBJECTIVE: The aim of this study was to investigate the effects of epigallocatechin-3-gallate on the proliferation and apoptosis of odontogenic keratocyst (OKC) keratinocytes in vitro. MATERIALS AND METHODS: Keratinocytes isolated from the epithelial lining of the OKC were cultured in keratinocyte serum-free medium and identified by CK10, CK14, pan-cytokeratin and vimentin immunofluorescence staining. The cells were exposed to EGCG at different concentrations, and proliferation inhibition was measured by cell counting kit 8 assay. Cell cycle and apoptosis were assessed by flow cytometry, and expression of the WNT signalling pathway-related proteins FZD3 and JNK3 was detected by quantitative real-time PCR and Western blotting. Human oral keratinocytes (HOKs) were used as the control. RESULTS: The OKC keratinocytes were successfully cultured. The primary cells were tile-like and expressed the epithelial biomarkers CK10, CK14 and pan-cytokeratin. Epigallocatechin-3-gallate inhibited cell proliferation in a dose- and time-dependent manner, arrested cell cycle in the G1 phase and induced apoptosis of OKC keratinocytes. FZD3 and JNK3 were overexpressed in OKC keratinocytes compared with HOKs and were downregulated by epigallocatechin-3-gallate treatment. CONCLUSION: Epigallocatechin-3-gallate inhibited proliferation and induced apoptosis in OKC keratinocytes, possibly by suppressing the WNT/JNK signalling pathway. It may thus be potentially used for OKC treatment.

Dietary nitrate protects submandibular gland from hyposalivation in ovariectomized rats via suppressing cell apoptosis.

Xerostomia, a major oral symptom of menopause, is a subjective feeling of dry mouth associated with oral pain and difficulties in deglutition and speech, which significantly reduces patient's quality of life. Dietary nitrate, which can be converted to nitric oxide, has multiple physiological functions in the body, including antioxidant activity and vasodilatation; however, its protective effect against xerostomia remains poorly understood. The present study aimed to evaluate the effects of dietary nitrate on estrogen deficiency-induced xerostomia. We established an ovariectomized (OVX) rat model, which included five groups: sham-operated, OVX, OVX + 0.4 mM nitrate, OVX + 2 mM nitrate, and OVX + 4 mM nitrate (n = 6). After ovariectomy, animals in the nitrate treatment groups received appropriate amounts of sodium nitrate dissolved in distilled water for 3 months. The results showed that nitrate treatment reduced body weight and water intake, and increased serum nitrate and nitrite levels. Furthermore, nitrate uptake increased saliva secretion as evidenced by saliva flow rates and aquaporin 5 expression, and alleviated histological lesions as evidenced by reduction of the fibrotic area and cell atrophy in the salivary glands. Although protective effects of nitrate against estrogen deficiency-induced xerostomia were observed at all doses, treatment with 2 mM nitrate was more effective than that with 0.4 mM and 4 mM nitrate. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and caspase-3 expression analyses showed that nitrate also protected cells from apoptosis, possibly through upregulation of Cu-Zn superoxide dismutase (Cu-Zn SOD) known to inhibit oxidative stress-related apoptosis. Our findings indicate that nitrate could improve functional activity of the salivary glands in OVX rats by suppressing apoptosis and upregulating Cu-Zn SOD expression, suggesting that dietary nitrate may potentially prevent hyposalivation in menopausal women.

Repair of buccal mucosa and floor of mouth defects using keystone design perforator island flap.

OBJECTIVE: To assess the feasibility of utilizing the keystone design perforator island flap (KDPIF) for the repair of small to medium-sized defects in the buccal mucosa and floor of mouth (cT1-2 stage tumor). STUDY DESIGN: We conducted a retrospective analysis of eight patients who underwent KDPIF to address oral defects at the Affiliated Hospital of Qingdao University between June 2021 and September 2022. Patient information, including medical history, defect site, flap size, operative time, hospital stay, complications, and postoperative recovery of oral function, was comprehensively evaluated. RESULTS: Eight patients (6 females and 2 males) underwent reconstruction using KDPIF. The mean operation time was 58.5 minutes (55-63 minutes), with an average length of stay of 3.5 days (3-5 days). None of the 8 cases (100%) exhibited flap splitting necrosis or infection. Moreover, no scar contracture was observed, and oral functions, including the degree of opening, type of opening, tongue mobility, speech function, and swallowing function, were successfully restored. One patient (12.5%) experienced bleeding from the incision on the first postoperative day, but following compression, hemostasis was achieved, and the incision healed well. CONCLUSIONS: KDPIF demonstrates technical feasibility and suitability for repairing small to medium-sized buccal mucosa and floor of mouth defects (cT1-2).