In-office tooth bleaching with 38% hydrogen peroxide promotes moderate/severe pulp inflammation and production of ll-1ß, TNF-ß, GPX, FGF-2 and osteocalcin in rats

Abstract Objectives: To study the intensity of inflammatory infiltrate and production of interleukin-1β (ll-1β), tumor necrosis factor-β (TNF-β), fibroblast growth factor-2 (FGF-2), glutathione peroxidase (GPX), and osteocalcin in response to in-office tooth bleaching in rats. Material and Methods: Twenty male Wistar rats were randomized into four groups (n=5) according to the received treatment (tooth bleaching or no treatment - control) and the period of euthanasia after treatment (24 h or 10 days). We performed tooth bleaching using a 38% hydrogen peroxide gel on maxillary and mandibular incisors. After euthanasia, incisors (20 per group) were processed for histological analysis, immunohistochemistry staining of ll-1β, TNF-β, FGF-2 and GPX and osteocalcin by immunofluorescence. We analyzed data using the Mann-Whitney and Kruskal-Wallis/Dunn tests (p<0.05). Results: The bleached groups presented statistically significant differences regarding the pulp inflammation stage compared with the control groups. Bleached teeth showed moderate/severe inflammatory infiltrate and control groups presented absent inflammatory cells or a negligible number of mononuclear cells (p<0.001) at two times (24 h and 10 days). There was strong staining for ll-1β, TNF-β, and GPX in bleached groups at 24 h and strong staining for ll-1β, TNF-β, GPX and FGF-2 at 10 days. After 10 days of tooth bleaching, the bleached group showed a statistically superior amount of osteocalcin than the other groups (p<0.01). Conclusions: Tooth bleaching with 38% hydrogen peroxide causes severe pulp inflammation, but characteristics of tissue repair after 10 days.

Efecto de la vitamina C, sobre la actividad de glutation peroxidasa y la formación de ateromas, en conejos expuestos a dieta hiperlipidémica / Effects vitamin C, on glutathione peroxidase activity and atheroma formation, in rabbits exposed to a hyperlipidaemic diet

El estrés oxidativo juega un papel muy importante en la aterosclerosis; de hecho existe evidencias que indican que los antioxidantes son moléculas capaces de retardar y/o revertir el proceso aterosclerótico. El objetivo del presente estudio fue comparar el efecto de la vitamina C (Vit C), sobre la actividad de la Glutation peroxidasa (GPx) y la formación de ateromas en conejos. Se estudiaron 36 conejos divididos en 3 grupos: Grupo 1 (Control): conejarina, Grupo 2: huevo y conejarina, Grupo 3: huevo, conejarina y Vit C (100mg/diarios). el período experimental duró 12 semanas. Se determinó perfil lipídico por métodos enzimáticos y la actividad de GPx por cinética en 0 y 12va semana. Los conejos fueron sacrificados y se les realizó estudio histológico de su aorta. Los resultados revelaron un incremento en la actividad de la GPx en los grupos 2 y 3 con respecto al control en la 12va semana de experimentación (p<0,05). Hubo inhibición de lesiones ateroscleróticas en los conejos del grupo 3. En conclusión en condiciones de hiperlipidemia con o sin suplementación de Vit C, existe incremento en la actividad de GPx. Por otra parte, la Vit C disminuye y evita la progresión de ateromas.

Oxidative stress plays an important role in artherosclerosis; so antioxidants are molecules have been used to slow down or inihibit atherosclerosis. The objetive of the presents study was to compare the effect of Vitamin C (Vit C), on serum Glutathione peroxidase activity (GPx) and on the formation of aortic lesions in rabbits. 36 rabbits were studied: Group 1: "conejarina" (commercial rrabit food); Group 2: egg and conejarina, Group 3: egg, conejarina and Vit C (100mg/day). The experimental lasted 12 weeks. Lipid profile was done by enzymatic methods and GPx by kinetic method in weeks 0 and 12. Histological study of rabbit's aorta was done. GPx activity in groups 2 and 3, increased compared with controls, from weeks 12 of experimentation (o<0,05). There was inihition of aortic lesions in groups 3. In conclusion, under hyperlipidemic conditions, with or without Vit C supplementation, activity of GPx there is increase. Vit C reduces and prevents the progression of atheromas.

Effects of endocrine disrupting chemicals on expression of phospholipid hydroperoxide glutathione peroxidase mRNA in rat testes

Phospholipid hydroperoxide glutathione peroxidase(PHGPx), an antioxidative selenoprotein, is modulated byestrogen in the testis and oviduct. To examine whetherpotential endocrine disrupting chemicals (EDCs) affectthe microenvironment of the testes, the expression patternsof PHGPx mRNA and histological changes were analyzedin 5-week-old Sprague-Dawley male rats exposed to severalEDCs such as an androgenic compound [testosterone (50,200, and 1,000microg/kg)], anti-androgenic compounds [flutamide(1, 5, and 25mg/kg), ketoconazole (0.2 and 1mg/kg), anddiethylhexyl phthalate (10, 50, and 250mg/kg)], andestrogenic compounds [nonylphenol (10, 50, 100, and 250mg/kg), octylphenol (10, 50, and 250mg/kg), and diethyl-stilbestrol (10, 20, and 40microg/kg)] daily for 3 weeks via oraladministration. Mild proliferation of germ cells andhyperplasia of interstitial cells were observed in the testesof the flutamide-treated group and deletion of thegerminal epithelium and sloughing of germ cells wereobserved in testes of the diethylstilbestrol-treated group.Treatment with testosterone was shown to slightly decreasePHGPx mRNA levels in testes by the reverse transcription-polymerase chain reaction. However, anti-androgeniccompounds (flutamide, ketoconazole, and diethylhexylphthalate) and estrogenic compounds (nonylphenol,octylphenol, and diethylstilbestrol) significantly up-regulated PHGPx mRNA in the testes (p<0.05). Thesefindings indicate that the EDCs might have a detrimentaleffect on spermatogenesis via abnormal enhancement ofPHGPx expression in testes and that PHGPx is useful as abiomarker for toxicity screening of estrogenic or anti-androgenic EDCs in testes.

Effect of cadmium on tissue glutathione and glutathione peroxidase in rats: influence of selenium supplementation.

Administration of cadmium (2.5 mg/kg, sc on alternate days for 3 weeks) to male albino rats led to significant accumulation of cadmium and metallothionein in the liver and kidneys. The activity of glutathione peroxidase was significantly decreased whereas, the concentration of glutathione was increased in these organs. Glycine-l-14C incorporation studies showed enhanced synthesis of glutathione in kidney but not in the liver. Selenium supplementation (1 mg/kg/day orally) failed to prevent these cadmium-induced changes, although it resulted in very high accumulation of selenium in these organs indicating the formation of cadmium-selenium complex.