Lactoferrin downregulates the expression of toll like receptor 4 stimulated by lipopolysaccharide in human periodontal ligament cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To examine the role of lactoferrin (LF) on Toll like receptor 4 (TLR4) stimulated by lipopolysaccharide (LPS) in human periodontal ligament cells (hPDLCs).</p><p><b>METHODS</b>Primary hPDLCs were cultured by tissue block enzymolytic method. Cells obtained from four passages were identified and used in this experiment. Cells without stimulation served as the controls and cells treated with LPS (0.1 microg x mL(-1)) comprised the LPS group. The LPS + LF group was pretreated with LPS (0.1 microg x mL(-1)) for 2 h, and then treated with LF (10 microg x mL(-1)). Four hours after LF stimulation, the mRNA expression levels of TLR4 were examined by real-time quantitative polymerase chain reaction (RT-PCR). The protein expression of TLR4 was observed by cell immunofluorescence staining after LF stimulation of 24 hours.</p><p><b>RESULTS</b>TLR4 mRNA expression in the LPS + LF group was significantly more decreased than that in the LPS group (P < 0.05), but exhibited no difference with that in the control group (P > 0.05). Cell immunofluorescence staining showed that the protein expression of TLR4 in the LPS + LF group was significantly more decreased than that in the LPS group (P < 0.05), but exhibited no difference with that in the control group (P > 0.05).</p><p><b>CONCLUSION</b>LF can decrease the expression of TLR4 stimulated by LPS in hPDLCs, thus presenting potential application for controlling the TLR4 immune pathway of periodontitis.</p>

vitro study of dentin hypersensitivity treated by 980-nm diode laser

To investigate the ultrastructural changes of dentin irradiated with 980-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of 980-nm diode laser in the treatment of dentin hypersensitivity [DH]. Twenty extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into four areas and was irradiated by 980-nm diode laser under different parameters: Group A: control group, 0 J/cm[2]; Group B: 2 W/CW [continuous mode], 166 J/cm[2]; Group C: 3W/CW, 250 J/cm[2]; and Group D: 4W/CW, 333 J/cm[2]. Ten additional extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into two areas and was irradiated by 980-nm diode laser: Group E: control group, 0 J/cm[2]; and Group F: 2.0 W/CW, 166 J/cm[2]. The morphological alterations of the dentin surfaces and odontoblasts were examined with scanning electron microscopy [SEM], and the morphological alterations of the dental pulp tissue irradiated by laser were observed with an upright microscope. The study demonstrated that dentinal tubules can be entirely blocked after irradiation by 980-nm diode laser, regardless of the parameter setting. Diode laser with settings of 2.0 W and 980-nm sealed exposed dentin tubules effectively, and no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. Irradiation with 980-nm diode laser could be effective for routine clinical treatment of DH, and 2.0W/CW [166 J/cm[2]] was a suitable energy parameter due to its rapid sealing of the exposed dentin tubules and its safety to the odontoblasts and pulp tissue