Effect of glucosamine sulphate on the temporomandibular joint of ovariectomised rats.

Glycosamine is an amino-monosaccharide present in connective and cartilage tissues that contribute to the maintenance, resistance, flexibility, and elasticity of these tissues. This study aimed to determine the in vivo effects of glucosamine sulphate (GS) on the temporomandibular joint (TMJ) of ovariectomised rats (OVX).Thirty-two rats were distributed into four groups as follows: G1, sham-OVX+saline solution; G2, sham-OVX+glucosamine sulphate (80mg/kg) - oral administration; G3, OVX+saline solution; G4, OVX+glucosamine sulphate (80mg/kg) - oral administration. Animals were treated for seven days. The TMJ was removed and stained with toluidine blue. The thickness of the cartilage layers and cytokines IL-1ß, IL-6, and TNF-α levels were determined by histomorphometry and immunoassay, respectively. The administration of GS to OVX females did not change the thickness of condylar cartilage when compared with the other groups (p>0.05). There was an increase in the total cartilage thickness in sham-OVX females. IL-1ß and TNF-α levels were significantly lower in sham-OVX females than in OVX females, indicating that ovariectomy acts as potent cytokine inducer. IL-6 levels were significantly higher in sham-OVX females. GS did not affect cytokine production in OVX females (p>0.05). In conclusion, the administration of GS did not affect cytokine levels, but did induce an increase in the total thickness of the TMJ condylar cartilage in sham-OVX rats.

The effect of omega-3 in temporomandibular joint synovial tissues of rats with induced arthritis: pilot study.

This study evaluated the effect of systemic administration of omega-3 on the expression of interleukins IL-1ß and IL-10 and tumour necrosis factor alpha (TNF-α) and on the thickness of cartilage in the temporomandibular joint (TMJ) inflammatory model induced by complete Freund's adjuvant (CFA). Thirty-two adult rats were divided equally into four groups: control, CFA (induced arthritis), and induced arthritis animals treated with dexamethasone or omega-3. The TMJs were then removed and assigned to histomorphometric analysis or immunoassay. The Kruskal-Wallis test with Dunn post hoc test was applied to the data; the significance level was set at 5%. IL-1ß levels (median; interquartile range) were higher (P<0.0001) in the CFA group (46.4 ng/ml; 39.4-53.3) than in the control group (1.81 ng/ml; 1.5-5.4), but there were no differences between the control, omega-3, and dexamethasone groups. TNF-α levels were also higher (P<0.0001) in the CFA group (122.7 ng/ml; 92.9-284.7) than in the control group (29.1 ng/ml; 23.7-31.3). IL-10 levels were lowest (P<0.0001) in the CFA group (73.5 ng/ml; 52.8-90.5), and no differences were found amongst the other groups. In conclusion, omega-3 successfully reduced the damage in the TMJ of induced arthritis rats. Further investigations are warranted to confirm whether the administration of omega-3 has a comparable effect to glucocorticoids in rheumatoid arthritis patients.

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-1ß 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.

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 17ß-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-1ß, IL-6, and tumour necrosis factor alpha (TNF-α)) were measured by histomorphometry and ELISA, respectively. Kruskal-Wallis/Dunn's 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-1ß 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.

Effect of particles of ashes produced from sugarcane burning on the respiratory system of rats.

The practice of burning sugarcane obtained by non-mechanized harvesting exposes workers and the people of neighboring towns to high concentrations of particulate matter (PM) that is harmful to health, and may trigger a series of cardiorespiratory diseases. The aim of this study was to analyze the chemical composition of the micro-particles coming from sugarcane burning residues and to verify the effects of this micro-particulate matter on lung and tracheal tissues. Micro-particulate matter (PM10) was obtained by dissolving filter paper containing burnt residues in NaCl solution. This material was instilled into the Wistar rats' nostrils. Histological analyses (hematoxylin and eosin - HE) of cardiac, lung and tracheal tissues were performed. Inflammatory mediators were measured in lung tissues by using ELISA. The chemical composition of the particulate material revealed a large quantity of the phthalic acid ester, high concentrations of phenolic compounds, anthracene and polycyclic aromatic hydrocarbons (PAH). Histological analysis showed a reduction in subjacent conjunctive tissue in the trachea, lung inflammation with inflammatory infiltrate formation and reduction of alveolar spaces and a significant increase (p<0.05) in the release of IL-1α, IL-1ß, IL-6, and INF-γ in the group treated with PM10 when compared to the control group. We concluded that the burning sugarcane residues release many particles, which have toxic chemical compounds. The micro-particulate matter can induce alterations in the respiratory system.

Effect of diazepam on temporomandibular joints in rats with increased occlusal vertical dimension.

Anxiolytic agents, mainly benzodiazepines, have been used to treat symptomatic disorders of the temporomandibular joint (TMJ). Our aim was to evaluate the effect of diazepam on the TMJ of rats with increased occlusal vertical dimension (iOVD). Forty male rats were randomly assigned to 4 groups: control rats were given sham iOVD plus saline solution daily for 7 days. The first experimental group was given sham iOVD plus diazepam 2.5mg/kg/intramuscularly daily for 7 days (diazepam alone group); the second had iOVD induced in molars for 7 days plus saline daily for 7 days (iOVD alone group); and the third had iOVD induced in molars for 7 days plus diazepam 2.5mg/kg/intramuscularly daily for 7 days (iOVD plus diazepam group). At the end of each experiment the animals were killed and their bilateral TMJs were removed, randomly stained with haematoxylin and eosin and sirius-red, and immunoassayed. The thickness of condylar cartilage and of fibrous, proliferating, mature, and hypertrophic layers, number of collagen fibres, and the articular area were measured. Proinflammatory cytokines (interleukin (IL)-1α, IL-1ß, IL-6, and tumour necrosis factor (TNF)-α) were also measured. ANOVA and Tukey's tests or the Kruskal-Wallis test were used to compare data among groups (α=5%). Condylar cartilage was thicker in the control group than in the other groups, the diazepam alone group being thicker than the other 2 experimental groups. There were fewer collagen fibres in the 2 groups given diazepam than in the other 2 groups, and there were no significant differences in the area of cartilage among groups. The controls had lower concentrations of all cytokines (p<0.05) than the 3 experimental groups, except for IL-6. Both iOVD groups had higher concentrations of IL-1α, IL-1ß, and IL-6 than the diazepam alone group. Diazepam alone was associated with increased concentrations of all cytokines except IL-6. We conclude that both iOVD and diazepam induced significant changes in rats' articular cartilage.