INitial Steps of Insulin Action in Parotid Glands of Male Wistar Rats.

The parotid gland is the largest salivary gland. It produces watery saliva, rich in proteins (amylase, lysozymes, and antibodies). Due to the gland's morphological cytoarchitecture composed of only serous acini, it contributes almost 50% of total salivary volume upon stimulation. It has been reported that the prevalence of saliva secretion impairments, periodontitis, delayed wound healing, and xerostomia increase in diabetic patients. Herein we evaluated the acute effects of insulin on insulin receptor phosphorylation status and its substrates IRS-1 and IRS-2 in the parotid glands of adult male Wistar rats, using Western blot analyses. We confirmed an acute effect of insulin on IR/IRS/PI3K/Akt and MAPK intracellular pathway activation in the parotid glands of male Wistar rats similar to the classical metabolic targets of the hormone, like the liver.

Effect of vitamin C and E on oxidative stress and antioxidant system in the salivary glands of STZ-induced diabetic rats.

OBJECTIVE: We examined the effects of vitamin C and E supplementation in the prevention of oxidative stress in the salivary glands of STZ-induced diabetic rats. DESIGN: Forty-eight male Wistar rats were divided into six groups (n = 8 in each): control (C), control supplemented with vitamin C (Cvc) and E (Cve), diabetic (D), and diabetic supplemented with vitamin C (Dvc) and E (Dve). Vitamin C (150 mg/kg) and E (300 mg/kg) were daily administered for 21 days. Serum ascorbic acid and α-tocopherol levels were quantified. Glandular levels of hydrogen peroxide (H2O2), superoxide anion (O2-), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), malondialdehyde (MDA) and the total antioxidant status (TAS) were estimated. RESULTS: Vitamin C and E levels were reduced in D group. Vitamin C decreased the levels of O2- in the salivary gland of diabetic rats. Vitamin E increased the concentration of O2- in PA gland of diabetic animals. In the SM gland of the diabetic group, MDA, SOD, GPx and TAS increased. Dve presented reduced SOD activity and increased GR, GPx, and MDA. Dve increased GPx, Gr and TAS levels. In the PA gland, MDA, SOD, CAT, GPx, GR, and TAS were similar in C and D. TAS, SOD, CAT, GPx, and GR increased in Dvc. Vitamin E supplementation resulted in increased MDA and CAT levels and reduced SOD activity. CONCLUSION: In the SM glands of the diabetic rats, vitamin C supplementation improved the antioxidant system, while vitamin E acted as pro-oxidant.

Oxidative stress and the antioxidant system in salivary glands of rats with experimental chronic kidney disease.

OBJECTIVE: This study aims to analyze the presence of oxidative stress and activity of the antioxidant system in the parotid and submandibular salivary glands of rats with Chronic Kidney Disease (CKD). DESIGN: Sixteen male wistar rats were divided into two groups (n = 8, each): control rats and rats with CKD. CKD was induced by 5/6 nephrectomy. Blood urea nitrogen and serum creatinine clearance were quantified. Malondialdehyde, superoxide dismutase, glutathione peroxidase, glutathione reductase, catalase, total antioxidant status, ascorbic acid, α-tocopherol, superoxide anion, and hydrogen peroxide concentrations were assessed. RESULTS: In CKD rats, blood urea nitrogen, serum creatinine, and proteinuria concentrations were increased, while creatinine clearance was reduced. In the submandibular gland, superoxide anion concentration was increased significantly (p < 0.05). Hydrogen peroxide and superoxide anion concentrations were reduced in the parotid gland. CKD rats presented increased malondialdehyde concentration, total antioxidant status, superoxide dismutase, and glutathione reductase activities only in the parotid gland (p < 0.05). CONCLUSION: Oxidative stress and changes in the antioxidant system were found in the parotid and submandibular salivary glands in an experimental model of CKD induced by 5/6 nephrectomy.

Assessment of oxidative stress in saliva of children with dental erosion.

OBJECTIVE: To evaluate oxidative stress in saliva of children with dental erosion as compared to children with no erosion. METHODS: One single examiner, trained and prepared to make diagnosis of dental erosion according to the Basic Erosive Wear Examination index, selected 40 children aged 4 to 6 years, who attended a pediatric dentistry prevention clinic. Two groups were formed - one comprising children with dental erosion (n=22), and another with no dental erosion (n=18). The quantity of dental biofilm was verified using the Simplified Index of Oral Hygiene, and unstimulated saliva was collected for biochemical analyses. The following were assessed in saliva: flow rate, buffering capacity, pH, and total protein concentration. Malondialdehyde levels were also verified to determine oxidative stress and total antioxidant status. RESULTS: The quantity of biofilm was smaller in children with mean dental erosion±standard deviation (0.76±0.25), as compared to those with no dental erosion (1.18±0.28). There was no statistical difference in saliva parameters of oxidative stress in children with dental erosion. CONCLUSION: The activity of oxidative stress in saliva did not influence dental erosion process when in its early stages.

Assessment of oxidative stress in saliva of children with dental erosion / Avaliação do estresse oxidativo da saliva de crianças com erosão dentária

ABSTRACT Objective To evaluate oxidative stress in saliva of children with dental erosion as compared to children with no erosion. Methods One single examiner, trained and prepared to make diagnosis of dental erosion according to the Basic Erosive Wear Examination index, selected 40 children aged 4 to 6 years, who attended a pediatric dentistry prevention clinic. Two groups were formed - one comprising children with dental erosion (n=22), and another with no dental erosion (n=18). The quantity of dental biofilm was verified using the Simplified Index of Oral Hygiene, and unstimulated saliva was collected for biochemical analyses. The following were assessed in saliva: flow rate, buffering capacity, pH, and total protein concentration. Malondialdehyde levels were also verified to determine oxidative stress and total antioxidant status. Results The quantity of biofilm was smaller in children with mean dental erosion±standard deviation (0.76±0.25), as compared to those with no dental erosion (1.18±0.28). There was no statistical difference in saliva parameters of oxidative stress in children with dental erosion. Conclusion The activity of oxidative stress in saliva did not influence dental erosion process when in its early stages.

RESUMO Objetivo Avaliar o estresse oxidativo da saliva de crianças que possuíam erosão dentária, comparadas àquelas que não apresentavam esta situação. Métodos Um único examinador, treinado e calibrado para o diagnóstico de erosão dentária, segundo o índice de Basic Erosive Wear Examination, selecionou 40 crianças de 4 a 6 anos de idade que frequentavam uma clínica de prevenção de odontopediatria. Dois grupos foram formados - um com aquelas que apresentavam erosão (n=22) e outro sem erosão (n=18). A quantidade do biofilme dental foi obtida utilizando o Índice de Higiene Oral Simplificado, tendo sido feita a coleta de saliva não estimulada para as análises bioquímicas. O fluxo salivar, a capacidade tampão da saliva, o pH salivar e a proteína total da saliva foram avaliados. Também foi verificado o valor do malondialdeído para determinação do estresse oxidativo e o total antioxidante. Resultados A quantidade de biofilme foi menor nas crianças, com erosão dentária média±desvio padrão (0,76±0,25) comparadas àquelas sem erosão dentária (1,18±0,28). Não houve diferença estatística nos parâmetros salivares de estresse oxidativo em crianças com erosão dentária. Conclusão A ação do estresse oxidativo na saliva não influenciou na erosão dentária, quando ainda nos estágios iniciais.

Reduced salivary flow rate and high levels of oxidative stress in whole saliva of children with Down syndrome.

AIM: To investigate salivary parameters between children with Down Syndrome (DS) and without DS. MATERIALS AND METHODS: Stimulated whole saliva was collected from 18 children with DS and 23 without DS. Salivary flow rate, pH, and salivary buffering capacity were determined. Cariogenic microorganisms were quantified by culture, and periodontopathogens by quantitative real-time polymerase chain reaction. The antioxidant profile was quantified spectrophotometrically, while malondialdehyde (MDA) was quantified by high-performance liquid chromatography. Data were analyzed by Mann-Whitney test and Spearman correlation (α = 0.05). RESULTS: Salivary flow rate was significantly lower in DS than in controls (p < 0.0001). Significant higher difference was observed for total protein dosage (p < 0.0001), superoxide dismutase activity (SOD) (p = 0.0002), and MDA (p < 0.001) in DS group. CONCLUSIONS: Reduced salivary flow rate might be an important factor in oral diseases development. High salivary levels of SOD and MDA show the significant influence of the oxidative stress and the early-onset periodontal disease in DS people.

Influence of Sexual Hormones on Neural Orofacial Perception.

OBJECTIVE: To investigate the trigeminal somatosensory (thermal, pain, tactile, vibratory, and electric), gustative (salty, bitter, sweet, sour), and olfactory thresholds in healthy women during the menstrual cycle and investigate any association with estradiol and progesterone levels in saliva. METHODS: We examined/tested 39 women between age 19 and 47 years and with regular menstrual cycles and no comorbidities. All women were informed about the purposes of the study, and only those who signed the informed consent were included. The tests were performed at three stages within the cycle: menstrual phase, follicular phase, and luteal phase. The procedure consisted of saliva collection at the beginning of each session to measure hormone levels, salivary flow, somatosensory evaluation with quantitative sensory testing applied to the right trigeminal maxillary branch and right forearm, gustative (sweet [glucose], salt [sodium chloride], sour [citric acid], and bitter [urea]) and olfactory (isopropanol at different concentrations) thresholds. RESULTS: During the menstrual cycle, thresholds for sweet, salty, sour, cold, vibration, and deep pain decreased, but warmth, electrical, and superficial pain thresholds increased. The bitter threshold was high, and the olfactory threshold was low in the follicular phase. Low estrogen levels were correlated to high deep pain thresholds in the forearm ( P = 0.008) and face ( P = 0.041), high tactile thresholds ( P = 0.001), and high superficial pain ( P = 0.006) thresholds in the face. High levels of progesterone were associated with a high deep pain threshold in the face and a high salty threshold ( P < 0.001). CONCLUSION: Estrogen and progesterone seem to be involved in sensory neuromodulation in women during the menstrual cycle.

The antioxidant effects of green tea reduces blood pressure and sympathoexcitation in an experimental model of hypertension.

BACKGROUND: Oxidative stress is a key mediator in the maintenance of sympathoexcitation and hypertension in human and experimental models. Green tea is widely known to be potent antioxidant. OBJECTIVE: We aimed to evaluate the effects of green tea in a model of hypertension. METHODS: Hypertension was induced by the nitric oxide synthase inhibitor [N-nitro-L-arginine-methyl-ester (L-NAME); 20 mg/kg per day, orally, for 2 weeks] in male Wistar rats. After the first week of L-NAME treatment, animals received green tea ad libitum for 1 week. At the end of the treatment period, blood pressure, heart rate, baroreflex sensitivity, renal sympathetic nerve activity, and vascular and systemic oxidative stress were assessed. RESULTS: L-NAME-treated animals exhibited an increase in blood pressure (165 ±â€Š2 mmHg) compared with control rats (103 ±â€Š1 mmHg) and green tea treatment reduced hypertension (119 ±â€Š1 mmHg). Hypertensive animals showed a higher renal sympathetic nerve activity (161 ±â€Š12 spikes/s) than the control group (97 ±â€Š2 spikes/s), and green tea also decreased this parameter in the hypertensive treated group (125 ±â€Š5 spikes/s). Arterial baroreceptor function and vascular and systemic oxidative stress were improved in hypertensive rats after green tea treatment. CONCLUSIONS: Taken together, short-term green tea treatment improved cardiovascular function in a hypertension model characterized by sympathoexcitation, which may be because of its antioxidant properties.

Síntese e caracterização de nanopartículas de hidroxiapatita funcionalizadas e análise da interação destas com o tecido dentinário / Synthesis and characterization of functionalized hydroxyapatite nanoparticles and analysis of the interaction in dentin

A hidroxiapatita (HA) é o principal constituinte mineral de ossos e dentes, e têm sido foco de grande interesse na biomedicina devido sua excelente biocompatibilidade e bioatividade, em especial para aplicação em implantes dentários e ortopedia. Na odontologia estudos mostram o sucesso do uso de nanopartículas (NP) de HA para tratamento de hipersensibilidade dentinária, remineralização de lesões de cárie em esmalte, reparação e prevenção de lesões de erosão iniciais. No entanto, existem evidências que o tamanho do cristal desempenha um papel essencial na formação dos tecidos duros e possui significante influência nas propriedades intrínsecas destes cristais, incluindo solubilidade e, consequentemente, biocompatibilidade. Este trabalho teve como objetivo verificar a síntese e caracterização de nanopartículas de hidroxiapatita funcionalizadas e avaliar a influência de sua aplicação no processo adesivo em dentina. Nanopartículas de HA com diferentes tamanhos e morfologia foram sintetizadas pelo método de precipitação em solução aquosa. Foi investigada a influência de dois novos ligantes, ácido deoxicólico (AD) e ácido abiético (AB), no preparo da NP de HA. As NP foram caracterizadas através das análises de espectroscopia por dispersão de raios X (EDX), Difratometria de Raios X (DRX), Espalhamento de Luz Dinâmica (DLS), Microscopia Eletrônica de Transmissão (MET), Microscopia Eletrônica de Varredura (MEV), Microscopia de Força Atômica (AFM). Os resultados mostraram que a adição destes ligantes alteram a morfologia mas não o arranjo cristalino da HA. Para o estudo da interação das NP de HA com o colágeno foi utilizado a NP modificada por AD...

Hydroxyapatite (HA) is the major mineral component of bones and teeth, and has been the focus of great interest in biomedicine because of its excellent biocompatibility and bioactivity, in particular for application in dental and orthopedic implants. In dentistry studies have shown the successful use of nanoparticles (NP) of HA for the treatment of dentin hypersensitivity, remineralization of caries lesions in enamel, repair and injury prevention of initial erosion. However, there is evidence that the size of the crystal plays an essential role in the formation of hard tissues and has significant influence on the intrinsic properties of these crystals, including solubility and biocompatibility. This study aims to verify the possibility of functionalized hydroxyapatite nanoparticles and evaluate possible benefits of using these during the adhesive process in dentin. HA with different sizes and morphology were synthesized by precipitation method in aqueous solution. Furthermore, the influence of two new ligands, deoxycholic acid (AD) and abietic acid (AB) in the preparation of HA NP were investigated. The NP were characterized by analysis of EDX, DRX, DLS...

Laser irradiation affects enzymatic antioxidant system of streptozotocin-induced diabetic rats.

The aim of the present study was to analyze the effect of low-power laser irradiation in the antioxidant enzymatic system of submandibular (SMG) and parotid (PG) salivary glands of streptozotocin-induced diabetic rats. The animals were randomly divided into six groups: three diabetic groups (D0, D5, and D20) and three non-diabetic groups (C0, C5, and C20), according to laser dose received (0, 5, and 20 J/cm(2), respectively). Areas of approximately 1 cm(2) were demarcated in the salivary glands (each parotid and both submandibular glands) and after irradiated according to Simões et.al. (Lasers Med Sci 24:202-208, 2009). A diode laser (660 nm/100 mW) was used, with laser beam spot of 0.0177 cm(2). The group treated with 5 J/cm(2) laser dose was subjected to irradiation for 1 min and 4 s (total irradiation time) and the group treated with 20 J/cm(2) laser dose was subjected to irradiation for 4 min and 16 s. Twenty-four hours after irradiation the animals were euthanized and the salivary glands were removed for biochemical analysis. The total antioxidant values (TA), the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase enzymes were determined. SOD and CAT activities, as well as TA were higher in SMG of irradiated diabetic rats. However, in SMG of non-diabetic rats, laser irradiation decreased TA values and led to an increase in the CAT activity. In addition, there was a decrease in the activity of CAT in PG of diabetic and non-diabetic animals after laser irradiation. According to the results of the present study, low-power laser irradiation can affect the enzymatic antioxidant system of salivary glands of streptozotocin-induced diabetic rats.

Sialic acid reduction in the saliva of streptozotocin induced diabetic rats.

OBJECTIVE: Diabetes causes changes in the salivary glands and in the composition of saliva, as well as symptoms such as dry mouth and hyposalivation. Therefore, this study aimed at investigating changes in salivary secretion and composition, in response to parasympathetic stimuli, in diabetic rats induced with streptozotocin. DESIGN: Diabetes was induced by a single intraperitoneal injection of streptozotocin. Thirty days after diabetes induction, the animals were anaesthetized and salivation was stimulated by an intraperitoneal injection of Pilocarpine (0.6mg/kg body weight) dissolved in distilled water. Saliva was collected for 40min and immediately stored at -80°C until analysis. The salivary flow rate, amount of total protein, amylase and peroxidase activities, and free and total sialic acid contents were measured. RESULTS: Salivary flow rate was reduced in the diabetic group (p<0.05). Moreover, increases in total protein amount and in amylase and peroxidase activities were observed in diabetic animals. No difference was observed for free sialic acid content between groups. On the other hand, a significantly decrease in the total sialic acid content was observed in the diabetic group (p<0.05). CONCLUSIONS: Our findings suggest that a decrease in sialic acid in the saliva of diabetic animals can be related to xerostomia reported by diabetic patients. However, further clinical trials are needed to verify if the decrease in sialic acid also occurs in human saliva.

Antioxidant enzymatic defense in salivary glands of streptozotocin-induced diabetic rats: a temporal study.

Hyperglycemia induces overproduction of superoxide and it is related to diabetic complications. In this study, we analyzed the antioxidant enzymatic defense and the lipid peroxidation of rat salivary glands in six different periods of diabetic condition. Ninety-six rats were divided into 12 groups: C7/14/21/28/45/60 (non-diabetic animals) and D7/14/21/28/45/60 (diabetic animals). Diabetes was induced by streptozotocin and the rats were euthanized after 7, 14, 21, 28, 45, or 60 days. Their parotid (PA) and submandibular (SM) glands were removed soon after the sacrifice and the total protein and malondialdehyde (MDA) concentrations, as well as, the superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities were determined. Twenty-one days after the diabetes induction, the SM glands showed an increase in SOD, CAT, and GPx activities, as well as, MDA concentration. Concerning the PA glands, an increase in the CAT activity and MDA content was observed throughout the observation period. The results suggest that diabetes can cause alterations on the salivary glands and that PA and SM glands react differently when exposed to diabetes condition. However, no impairment of antioxidant system was observed in the group whose diabetic condition had been induced 60 days earlier, herein named 60-day group.

Estudo do efeito da irradiação com laser de baixa intensidade no sistema antioxidante de glândulas salivares de ratas diabéticas induzidas por estreptozotocina / Effect of low power laser irradiation on the antioxidant system of salivary glands of diabetic rats induced by streptozotocin

O objetivo do presente estudo foi o de analisar o efeito da irradiação com laser em baixa intensidade no sistema antioxidante enzimático de glândulas salivares submandibular (GSM) e parótida (GP) de ratas diabéticas induzidas por estreptozotocina. As ratas foram inicialmente divididas em grupos não-diabéticas (C) e diabéticas (D) e mantidas pelo período experimental de 30 dias. No vigésimo nono dia as ratas foram subdivididas em seis grupos, sendo três grupos de animais não diabéticos (C0, C5 e C20) e três de animais diabéticos (D0, D5 e D20), de acordo com a dose de irradiação laser que cada grupo recebeu (0, 5 e 20 J/cm2 respectivamente). Para a indução do diabetes foi realizada a injeção intraperitoneal de estreptozotocina (60 mg/kg de peso corporal) dissolvida em tampão citrato de sódio 0,1 M, pH 4,5. Os animais pertencentes aos grupos C (não diabéticos) receberam a injeção somente do veículo. As glicemias foram verificadas 72 horas após a indução do diabetes, para a confirmação do estado diabético nos grupos D. Foram considerados diabéticos os animais que apresentaram glicemia superior a 250mg de glicose/dl de sangue. A irradiação com laser em baixa intensidade seguiu a metodologia determinada pelo método de Simões et. al. (2009). Os animais foram eutanasiados 24 horas após a irradiação, sendo imediatamente removidas as glândulas salivares para a realização das análises bioquímicas.

Foram determinados através de espectrofotometria, os valores de total antioxidante (TAS) e as atividades das enzimas superóxido dismutase (SOD), catalase (CAT) e glutationa peroxidase (GPx). Através da análise dos resultados podemos concluir que em GSM de ratas diabéticas o laser com dose de 20J/cm2 causou aumento na atividade da enzima SOD. E independente da dose, causou aumento nos valores de TAS e atividade da enzima CAT. Já em GSM de ratas não diabéticas a dose de 20J/cm2 causou diminuição dos valores de TAS. E independente da dose a irradiação com laser levou a um aumento da atividade da enzima CAT. Nas parótidas de ratas diabéticas, independente da dose, a irradiação com laser causou diminuição da atividade da enzima CAT. E em GP de ratas não diabéticas a dose de 5J/cm2 causou diminuição da atividade da enzima CAT.

The aim of the present study was to analize the effect of low-power laser irradiation in the antioxidant enzymatic system of submandibular (GSM) and parotid (GP) salivary glands of diabetic rats induced by streptozotocin. The rats were initially divided into non-diabetic animals (C) and diabetic-animals (D) and maintained by the experimental period of thirty days. Twenty-nine days after diabetes induction, the animals were randomly divided into six groups: three diabetic groups (D0, D5 and D20) and three non-diabetic groups (C0, C5 and C20), according with laser irradiation dose that each one received (0, 5 and 20J/cm2, respectively). For diabetes induction an intraperitoneal injection of streptozotocin (STZ) (60mg/Kg body weight), dissolved in 0.1M sodium citrate buffer, pH 4.5 was performed. In non-diabetic animals, only the citrate buffer was used. The diabetes condition was confirmed seventy-two hours after animals have received the STZ injection. Rats with blood glucose level higher than 14mM (250 mg/100ml) were considered diabetic. The laser irradiation was performed according to Simões et.al. method (2009)

Twenty-four hours after the irradiation rats were euthanized. Then, immediately after the euthanasia, salivary glands were removed for biochemical analysis. The total antioxidant values (TAS) and the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxide (GPx) enzymes were determined in spectrophotometer. Analyzing the results we can conclude that in GSM of diabetic rats the laser irradiation with 20J/cm2 increased the SOD activity. With the two different doses, increased the TAS values and CAT activity. However, in GSM of non-diabetic rats, laser irradiation with 20J/cm2, decreased the TAS values and led to an increase in CAT activity, regardless of the dose. In parotid glands laser irradiation decreased the CAT activity with either dose of 5J/cm2 or 20 J/cm2 and the laser irradiation with dose of 5J/cm2, decreased the CAT activity in parotid glands of non-diabetic rats.