Sidney Raimundo Figueroba

Dependence of cytokine levels on the sex of experimental animals: a pilot study on the effect of oestrogen in the temporomandibular joint synovial tissues

The aim of this study was to evaluate the effects of 17β-oestradiol (E2) on cartilage thickness and cytokine levels in the temporomandibular joint (TMJ). Thirty rats (15 female, 15 male) were orchidectomized (ORX), ovariectomized (OVX), or sham-operated. After 21 days, animals were assigned to six groups: (1) sham-ORX; (2) ORX; (3) ORX+E2; (4) sham-OVX; (5) OVX; and (6) OVX+E2. Treatments were administered daily for 21 days. The thickness of cartilage layers (fibrous, proliferative, maturation, and hypertrophic) and cytokine levels (interleukins IL-1α, IL-1β, IL-6, and tumour necrosis factor alpha (TNF-α)) were measured by histomorphometry and ELISA, respectively. Kruskal-Wallis/Dunns tests were used (alpha=5%). Sham-ORX showed thicker layers than ORX+E2, but not thicker than ORX. All layers, except the hypertrophic layer, were thicker in sham-OVX than OVX or OVX+E2. Although IL-1β levels were higher in castrated animals, E2 did not affect the level of this cytokine. IL-1α levels were higher in both ORX (P=0.0010) and ORX+E2 (P=0.0053) than in sham-ORX. However, E2 decreased IL-1α levels in OVX (P=0.0129). When compared to sham-ORX/OVX, IL-6 levels were not affected by E2 in males but were reduced in OVX (P=0.0079) and increased in OVX+E2 (P=0.0434). Levels of TNF-α were reduced by E2 in both ORX+E2 and OVX+E2. E2 treatment caused gender- and layer-dependent changes in the cartilage. Castration increased all cytokine levels, except for IL-6, without respect to gender.

The influence of altered occlusion on pro-inflammatory cytokine levels in the TMJ synovial tissues of rats.

OBJECTIVE The aim of this study was to evaluate whether altered occlusion affects both the condylar cartilage thickness and the cytokine levels of the TMJs of rats. DESIGN Thirty adult-male rats (n=30) were randomly assigned to three experimental conditions: a control group that underwent sham operations with unaltered occlusion; an FPDM group that underwent functional posterior displacement of the mandible that was induced by an incisor guiding appliance; and an iOVD group in which the increased occlusal vertical dimension was induced in the molars. The rats were subjected to the FPDM or iOVD model for 14 days and then killed. Both the right and left TMJs were removed and randomly assigned to examination with staining or immunoassay techniques. Toluidine blue staining was used to measure the thicknesses of the four layers of the articular cartilage (i.e., the fibrous, proliferating, mature, and hypertrophic layers). ELISA assays were used to assess the concentrations of the pro-inflammatory cytokines IL-1α, IL-1β, IL-6, and tumour necrosis factor (TNF-α). The measurements of the articular cartilage layers and cytokine concentrations were analyzed with ANOVA and Tukeys tests and Kruskal-Wallis and Dunn tests, respectively (α=5%). RESULTS The thickness of articular cartilage in the FPDM group (0.3±0.03mm) was significantly greater than those of the control (0.2±0.01mm) and iOVD (0.25±0.03mm) groups. No significant difference was observed between the control and iOVD groups. The four articular cartilage layers were thicker in the FPDM group than in the control and iOVD groups, and the latter two groups did not differ one from each other. Both the FPDM and iOVD groups exhibited higher cytokine levels than did the control (p<0.05) group. Compared to the FPDM group, the iOVD group exhibited significantly higher levels of IL-1β and TNF-α. CONCLUSION Both models induced inflammation in the TMJ and caused significant structural changes in the TMJ and surrounding tissues.

The effect of a hydroxyapatite impregnated PCL membrane in rat subcritical calvarial bone defects

OBJECTIVE The present study evaluated the effect of polymeric-nanofibers membranes impregnated with microparticulate hydroxyapatite (HA) in the subcritical calvarial bone defects (SCBD) healing. DESIGN PCL membranes with and without HA were obtained by electrospinning. SCBD were perforated (3.3mm) in left and right sides of 36 rat calvarias. The right-side SBCD of 18 animals was filled with HA mixed with blood clot and blood clot at the contralateral side. The remaining animals received PCL+HA membrane at the right-side SCBD and PCL membrane at the contralateral side. Animals were killed after 30, 60 and 90days after surgery. Bone defect volume (in mm3) was measured by tomography (CBCT). Qualitative histological analysis and SBCD area (in mm2) were measured. Quantitative data were submitted to Kruskal-Wallis/Dunn tests. RESULTS Reduction of SBCD volume was observed in all treatments but PCL. Association with HA significantly improved bone healing induced by PCL and blood clot. PCL+HA induced the lowest SBCD volume at 60 and 90days. Complete bone healing was not observed even at 90days in SCBD treated with blood clot. In every period, more bone formation was observed for SCBD treated with membranes. CONCLUSIONS We concluded that both PCL membrane and HA were able to improve bone healing.

Altered mandibular growth under functional posterior displacement in rats.

OBJECTIVE To test the null hypothesis that there is no difference in mandibular growth between growing rats with posterior functional mandibular displacement and growing rats without functional mandibular displacement. MATERIALS AND METHODS Twenty female Wistar rats (5 weeks old) were randomized into two groups: (1) control and (2) mandible posterior displacement in the occluded condition induced by an occlusal guiding appliance. After 8 weeks all animals were sacrificed, cone beam computed tomography scan images of the heads were taken using the classic I-CAT, and acrylic rapid-prototyped templates of the mandibles were constructed. Mandibular length, ramus height, and intercondylar distance were measured. Mandibular length and ramus height were submitted to the two-way analysis of variance, while intercondylar distance was analyzed by nonpaired Students t-test. RESULTS Mandibular length was bigger (P < .0001) in the control than in the experimental group, but no significant difference was found between the left and right sides (P  =  .9380). No significant differences were observed for ramus height and intercondylar distance. CONCLUSIONS The results of this study demonstrated that functional posterior displacement of the mandible in growing rats resulted in shorter mandibular length.

The action of anti-inflammatory agents in healthy temporomandibular joint synovial tissues is sex-dependent

This study evaluated the effects of dexamethasone, parecoxib, and glucosamine on cartilage thickness and cytokine levels in the temporomandibular joint (TMJ). Forty-eight rats (24 female, 24 male) were assigned to four treatments administered once daily for 7 days: control (saline intramuscularly), parecoxib (0.3mg/kg intramuscularly), dexamethasone (0.1mg/kg intramuscularly), and glucosamine (80mg/kg orally). The thickness of TMJ cartilage and levels of four cytokines were measured. Median cartilage thickness was higher in males than in females in the control (253.2 vs. 240.4μm, P=0.0036), parecoxib (227.3 vs. 192.1μm, P<0.0001), and dexamethasone (227.1 vs. 170.5μm, P=0.017) groups, but was lower in males in the glucosamine group (214.5 vs. 239.6μm, P=0.0001). IL-1β was not detected. Median IL-1α levels differed between males and females in the parecoxib group (0.08 vs. 0.04ng/ml, P=0.0055), but not in the control (0.07 vs. 0.06ng/ml), dexamethasone (0.06 vs. 0.04ng/ml), or glucosamine (0.08ng/ml vs. 0.06ng/ml) groups (all P>0.05). Only dexamethasone induced lower IL-6 levels in males than in females (median 4.6 vs. 2.1ng/ml, P=0.0044). Median TNF-α levels did not differ between males and females in the control (0.07 vs. 0.05ng/ml) or parecoxib (0.07 vs. 0.05ng/ml) groups (both P>0.05), but dexamethasone (0.09 vs. 0.05ng/ml, P=0.0002) and glucosamine (0.09 vs. 0.07ng/ml, P=0.0259) induced higher TNF-α levels in females. Thus, the effects of the three treatments on the levels of cytokines and thickness of condylar cartilage were sex-dependent.

Correlation between facial types and muscle TMD in women: an anthropometric approach

Temporomandibular disorders (TMD) affecting the articular disc and/or the facial muscles are common among the population, recording a higher incidence in women age 20-40 years. The aim of this study was to investigate the correlation between facial types and muscle TMD in women. This study comprised 56 women age 18 to 49 years, seeking treatment for TMD at the School of Medicine, Federal University of São Paulo. All of the study individuals were diagnosed with muscle TMD, based on the Research Diagnostic Criteria (RDC). Facial type was determined using the Facial Brugsch Index and classified as euryprosopic (short and/or broad), mesoprosopic (average width) and leptoprosopic (long and/or narrow). The data were submitted to the Chi-square test and ANOVA-Tukeys test to conduct the statistical analysis. The faces of 27 individuals were classified as euryprosopic (48%), 18 as mesoprosopic (32%), and 11 as leptoprosopic (20%). A statistically significant difference (Chi-square, p = 0.032) was found among the facial types, in that leptoprosopic facial types showed the lowest values for muscle TMD. A greater number (p = 0.0007) of cases of muscle TMD were observed in the 20 to 39 year-old subjects than in the subjects of other age segments. In conclusion, women with euryprosopic facial types could be more susceptible to muscle TMD. Further studies are needed to investigate this hypothesis.