Remifentanil Negatively Regulates RANKL-Induced Osteoclast Differentiation and Bone Resorption by Inhibiting c-Fos/NFATc1 Expression

Remifentanil is commonly used in operating rooms and intensive care units for the purpose of anesthesia and sedation or analgesia. Although remifentanil may significantly affect the bone regeneration process in patients, there have been few studies to date on the effects of remifentanil on bone physiology. The purpose of this study was to investigate the effects of remifentanil on osteoclast differentiation and bone resorption. Bone marrow-derived macrophages (BMMs) were cultured for 4 days in remifentanil concentrations ranging from 0 to 100 ng/ml, macrophage colony-stimulating factor (M-CSF) alone, or in osteoclastogenic medium to induce the production of mature osteoclasts. To determine the degree of osteoclast maturity, tartrate-resistant acid phosphatase (TRAP) staining was performed. RT-PCR and western blotting analyses were used to determine the effect of remifentanil on the signaling pathways involved in osteoclast differentiation and maturation. Bone resorption and migration of BMMs were analyzed to determine the osteoclastic activity. Remifentanil reduced the number and size of osteoclasts and the formation of TRAP-positive multinuclear osteoclasts in a dose-dependent manner. Expression of c-Fos and NFATC1 was most strongly decreased in the presence of RANKL and remifentanil, and the activity of ERK was also inhibited by remifentanil. In the bone resorption assay, remifentanil reduced bone resorption and did not significantly affect cell migration. This study shows that remifentanil inhibits the differentiation and maturation of osteoclasts and reduces bone resorption.

Propofol protects against oxidative-stress-induced COS-7 cell apoptosis by inducing autophagy

BACKGROUND: In oxidative stress, reactive oxygen species (ROS) production contributes to cellular dysfunction and initiates the apoptotic cascade. Autophagy is considered the mechanism that decreases ROS concentration and oxidative damage. Propofol shows antioxidant properties, but the mechanisms underlying the effect of propofol preconditioning (PPC) on oxidative injury remain unclear. Therefore, we investigated whether PPC protects against cell damage from hydrogen peroxide (H₂O₂)-induced oxidative stress and influences cellular autophagy. METHOD: COS-7 cells were randomly divided into the following groups: control, cells were incubated in normoxia (5% CO₂, 21% O₂, and 74% N₂) for 24 h without propofol; H₂O₂, cells were exposed to H₂O₂ (400 µM) for 2 h; PPC + H₂O₂, cells pretreated with propofol were exposed to H₂O₂; and 3-methyladenine (3-MA) + PPC + H₂O₂, cells pretreated with 3-MA (1 mM) for 1 h and propofol were exposed to H₂O₂. Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide thiazolyl blue (MTT) reduction. Apoptosis was determined using Hoechst 33342 staining and fluorescence microscopy. The relationship between PPC and autophagy was detected using western blot analysis. RESULTS: Cell viability decreased more significantly in the H₂O₂ group than in the control group, but it was improved by PPC (100 µM). Pretreatment with propofol effectively decreased H₂O₂-induced COS-7 cell apoptosis. However, pretreatment with 3-MA inhibited the protective effect of propofol during apoptosis. Western blot analysis showed that the level of autophagy-related proteins was higher in the PPC + H₂O₂ group than that in the H2O2 group. CONCLUSION: PPC has a protective effect on H₂O₂-induced COS-7 cell apoptosis, which is mediated by autophagy activation.

Remifentanil induces autophagy and prevents hydrogen peroxide-induced apoptosis in Cos-7 cells

BACKGROUND: This study investigated the effect of remifentanil pretreatment on Cos-7 cells exposed to oxidative stress, and the influence of remifentanil on intracellular autophagy and apoptotic cell death. METHODS: Cells were divided into 4 groups: (1) Control: non-pretreated cells were incubated in normoxia (5% CO₂, 21% O₂, and 74% N₂). (2) H₂O₂: non-pretreated cells were exposed to H₂O₂ for 24 h. (3) RPC+H₂O₂: cells pretreated with remifentanil were exposed to H₂O₂ for 24 h. (4) 3-MA+RPC+H₂O₂: cells pretreated with 3-Methyladenine (3-MA) and remifentanil were exposed to H₂O₂ for 24 h. We determined the cell viability of each group using an MTT assay. Hoechst staining and FACS analysis of Cos-7 cells were performed to observe the effect of remifentanil on apoptosis. Autophagy activation was determined by fluorescence microscopy, MDC staining, and AO staining. The expression of autophagy-related proteins was observed using western blotting. RESULTS: Remifentanil pretreatment increased the viability of Cos-7 cells exposed to oxidative stress. Hoechst staining and FACS analysis revealed that oxidative stress-dependent apoptosis was suppressed by the pretreatment. Additionally, fluorescence microscopy showed that remifentanil pretreatment led to autophagy-induction in Cos-7 cells, and the expression of autophagy-related proteins was increased in the RPC+H₂O₂ group. CONCLUSIONS: The study showed that remifentanil pretreatment stimulated autophagy and increased viability in an oxidative stress model of Cos-7 cells. Therefore, we suggest that apoptosis was activated upon oxidative stress, and remifentanil preconditioning increased the survival rate of the cells by activating autophagy.

Shear bond strength of the three different kinds of resin cement on CAD/CAM ceramic inlay / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the bond strengths between the latest CAD/CAM ceramic inlay and various resin cements which are used primarily for esthetic restoration. MATERIALS AND METHODS: Cylindrical ceramic blocks(Height: 5 mm, diameter: 3 mm) were fabricated by using Cerec3 and bonded on the dentin of the ninety extracted caries-free molars using three different kinds of resin cement(Unicem(R), Biscem(R), and Variolink II(R)) according to the manufacturer's instructions. Ninety specimens were divided into 3 groups according to three different kinds of resin cement. Half of each group were conducted thermocycling under the conditions of the 5 - 55degrees C, 5,000 cycle but the other half of them weren't. All specimens were kept in normal saline 37degrees C, for 24 hours before measuring the bond strength. The shear bond strength was measured by Universal testing machine with a cross head speed of 0.5 mm/min. The results were analyzed statistically by t-test and one-way ANOVA. RESULTS: Unicem(R) group showed the highest shear bond strength despite a slight decline by thermocycling. The shear bond strength of Unicem(R) group and ValiolinkII(R) group were significantly influenced by thermocycling, whereas Biscem(R) group was not influenced (P<.05). There were no significant differences in the bond strength between the three groups without thermocycling, but there was significant differences between Unicem(R) group and Valiolink II(R) group with thermocycling(P<.05). CONCLUSION: It has been shown to be clinically effective when the self-adhesive resin cements Unicem(R) and Biscem(R) were used instead of the etch-and-rinse resin cement Valiolink II(R) during the bonding of CAD/CAM ceramic inlay restorations with teeth.

Periodontal Status Following the Alignment of Buccally Impacted Maxillary Canine Teeth with Surgical Uncovering / 대한치주과학회지

The present study examines the effects of orthodontic treatment of surgically exposed impacted upper canines or ectopically erupted upper canines to periodontal condition and whether various opening procedures have significant difference in postoperative periodontal status. The subjects included 23 orthodontic patients(7 men, 16 women) with unilateral upper canine impaction treated either with closed eruption technique(group I), with apically positioned flap procedure(group II), and those with canines ectopically erupted through keratinized gingiva(group III). In each subject, the ectopic canine was orthodontically aligned, and changes in periodontal tissue were assessed by measuring keratinized gingival width, attached gingival width, probing depth and bone probing depth. In all three groups, the width of keratinized gingiva was preserved while showed no signs of detrimental periodontal condition such as gingival recession. In all three groups, no significant difference in periodontal pocket depth from control was observed. The width of attached gingiva was significantly greater in patients treated with apically positioned flap procedure(group II) than in patients on other groups.