Induction of alopecia areata in C3H/HeJ mice using polyinosinic-polycytidylic acid (poly[I:C]) and interferon-gamma.

Alopecia areata (AA) is a chronic, relapsing hair-loss disorder that is considered to be a T-cell-mediated autoimmune disease. Several animal models for AA have been created to investigate the pathophysiology and screen for effective therapeutic targets. As C3H/HeJ mice develop AA spontaneously in a low frequency, a novel animal model is needed to establish an AA-like condition faster and more conveniently. In this study, we present a novel non-invasive AA rodent model that avoids skin or lymph-node cell transfer. We simply injected C3H/HeJ mice subcutaneously with interferon-gamma (IFNγ) along with polyinosinic:polycytidylic acid (poly[I:C]), a synthetic dsRNA, to initiate innate immunity via inflammasome activation. Approximately 80% of the IFNγ and poly(I:C) co-injected mice showed patchy AA lesions after 8 weeks. None of the mice displayed hair loss in the IFNγ or poly(I:C) solely injection group. Immunohistochemical staining of the AA lesions revealed increased infiltration of CD4+ and CD8+ cells infiltration around the hair follicles. IFNγ and poly(I:C) increased the expression of NLRP3, IL-1ß, CXCL9, CXCL10, and CXCL11 in mouse skin. Taken together, these findings indicate a shorter and more convenient means of AA animal model induction and demonstrate that inflammasome-activated innate immunity is important in AA pathogenesis.

Effects of a calcium phosphate-coated and anodized titanium surface on early bone response.

PURPOSE: The aim of this study was to evaluate the effectiveness of a calcium phosphate (CaPO4)-coated and anodized titanium surface in vitro and in vivo. MATERIALS AND METHODS: A turned surface was employed as a negative control. A sandblasted/acid-etched surface and an anodized surface were used as positive controls, and a CaPO4-coated and anodized (CPA) surface was investigated as the experimental group. Surface characteristics were analyzed with field emission scanning electron microscopy, energy dispersive spectroscopy, and confocal laser scanning microscopy. In vitro osteoblastic differentiation was evaluated by alkaline phosphatase assay. In vivo bone response was analyzed using bone-to-implant contact (BIC) ratios and bone area (BA) of 2- and 4-week specimens obtained from six rabbits. RESULTS: The means and standard deviations for average height deviation (S(a)) and developed surface area ratio (S(dr)) were 0.32 ± 0.03 µm and 3.6% ± 1.5% for the turned group, 1.36 ± 0.11 µm and 56.7% ± 16.1% for the sandblasted/acid-etched group, 0.68 ± 0.02 µm and 50.9% ± 2.9% for the anodized group, and 0.67 ± 0.11 µm and 50.0% ± 16.9% for the CPA group. There were no significant differences in alkaline phosphatase activity among the groups at 7 and 14 days. In the in vivo experiment, the CPA group exhibited a significantly higher BIC ratio than the turned group, and the anodized and CPA groups showed significantly higher BA values than the others after 2 weeks. At 4 weeks, there was no significance in either BIC ratios or BA values among the groups. CONCLUSION: A CaPO(4) coating on an anodized surface may induce rapid osseointegration at the bone-implant interface and more bone formation near the implant surface.

Biomechanical evaluation of dental implants with different surfaces: Removal torque and resonance frequency analysis in rabbits.

STATEMENT OF PROBLEM: Macroscopic and especially microscopic properties of implant surfaces play a major role in the osseous healing of dental implants. Dental implants with modified surfaces have shown stronger osseointegration than implants which are only turned (machined). Advanced surface modification techniques such as anodic oxidation and Ca-P application have been developed to achieve faster and stronger bonding between the host bone and the implant. PURPOSE: The purpose of this study was to investigate the effect of surface treatment of titanium dental implant on implant stability after insertion using the rabbit tibia model. MATERIAL AND METHODS: THREE TEST GROUPS WERE PREPARED: sandblasted, large-grit and acid-etched (SLA) implants, anodic oxidized implants, and anodized implants with Ca-P immersion. The turned implants served as control. Twenty rabbits received 80 implants in the tibia. Resonance frequencies were measured at the time of implant insertion, 2 weeks and 4 weeks of healing. Removal torque values (RTV) were measured 2 and 4 weeks after insertion. RESULTS: The implant stability quotient (ISQ) values of implants for resonance frequency analysis (RFA) increased significantly (P < .05) during 2 weeks of healing period although there were no significant differences among the test and control groups (P > .05). The test and control implants also showed significantly higher ISQ values during 4 weeks of healing period (P < .05). No significant differences, however, were found among all the groups. All the groups showed no significant differences in ISQ values between 2 and 4 weeks after implant insertion (P > .05). The SLA, anodized and Ca-P immersed implants showed higher RTVs at 2 and 4 weeks of healing than the machined one (P < .05). However, there was no significant difference among the experimental groups. CONCLUSION: The surface-modified implants appear to provide superior implant stability to the turned one. Under the limitation of this study, however, we suggest that neither anodic oxidation nor Ca-P immersion techniques have any advantage over the conventional SLA technique with respect to implant stability.