The effects of zoledronic acid on the progression of experimental periodontitis in rats: histological and microtomographic analyses.

PURPOSE: Periodontitis is considered a local risk factor for medication-related osteonecrosis of the jaws (MRONJ). However, little is known about the progression of periodontitis in the presence of zoledronic acid (ZOL). The aim of this study was to evaluate the effects of the systemic use of ZOL on the progression of experimental periodontitis (EP) in rats, as ZOL could modulate the progression of periodontitis and concomitantly cause MRONJ in individuals with periodontitis. METHODS: Forty-eight male Wistar rats were randomly distributed in 6 groups (n=8 each). To induce EP, ligatures were placed around the right first mandibular molars. Three groups were treated with ZOL (0.15 mg/kg/week, intraperitoneal), and 3 with 0.9% saline solution (controls). In the ZOL/Lig30 and ZOL/Lig 15 groups, after 4 weeks of treatment with ZOL, EP was induced and euthanasia was performed after 30 and 15 days of EP induction, respectively. In both groups, the animals continued to receive ZOL after EP until the end of the experiment. In the Lig/ZOL group, EP was induced first, and 15 days later, ZOL was administered for 8 weeks, with euthanasia 1 week after the last dose. After euthanasia, the mandibles were evaluated using micro-computed microtomography (micro-CT) and histomorphometry. Bone loss was measured, and the presence of osteonecrosis was evaluated histologically. The data were evaluated using the Student t-test and the Mann-Whitney test, with a significance level of 5%. RESULTS: In the Lig/ZOL group, micro-CT revealed less alveolar bone resorption in the distal root (P<0.01) than in the control group (Lig/Con). Histomorphometric analysis confirmed less alveolar bone resorption in the Lig/ZOL group (P=0.001). Histologically, osteonecrosis was more common in the ZOL groups. CONCLUSION: ZOL decreased alveolar bone resorption in rats with EP. However, it presented a higher risk for MRONJ.

Moderate physical training counterbalances harmful effects of low-protein diet on heart: metabolic, oxidative and morphological parameters

Aims: Maternal low-protein diet induces several impairments on cardiac system. Conversely, moderate exercise has been widely recommended to health improvement due to its effects on heart function. Thus, we investigated whether the moderate physical training is capable to offset the lasting injuries of a maternal protein restriction on the hearts of male adult rats. Methods: Pregnant rats were divided into two groups: Control (C=17% casein) and undernutrition (U=8% casein). Offspring from the undernutrition group, at 60 days of life, were subdivided into undernutrition (U) and undernutrition+exercise (UT) groups. Treadmill exercise was performed: (8 weeks, 5 days/week, 60 min/day at 70% of VO2máx). 48 hours after last exercise session, tissues were collected for morphological and biochemical analysis. Results Despite the deleterious effect induced by low-protein diet, physical training was able to restore morphological parameters to similar levels to the control group. Additionally, oxidative stress index was also improved in UT group, due to the increase in antioxidant enzymatic defense. In metabolic enzymes, maternal low-protein diet induced a change in metabolism, and moderate physical training improved oxidative metabolism. Conclusion: We demonstrated that moderate physical training can offset the cardiac metabolism in adult rats that were exposed to a maternal low-protein diet.(AU)

Interferência da L-arginina e do exercício físico sobre a morfologia do músculo estriado esquelético em ratos jovens / L-arginine and physical exercise interference on the morphology of the skeletal muscle in young rats

INTRODUÇÃO: O exercício físico pode promover alterações anatomofisiológicas no músculo estriado esquelético e a ingestão do aminoácido L-arginina pode influenciar na morfometria da fibra muscular esquelética. OBJETIVO: Analisar a influência da L-arginina associada ao exercício físico sobre a fibra muscular esquelética. MÉTODOS: Foram utilizados 24 ratos da linhagem Wistar. Aos sete dias de vida, esses animais foram divididos em dois grupos: tratados com L-arginina (grupo-Ar; 300 mg/kg/dia) e tratados com volume equivalente do veículo - água destilada (grupo-Ag; controle). A L-arginina ou a água foi administrada diariamente por gavagem. Aos 15 dias de idade, os animais dos grupos Ar e Ag foram subdivididos de acordo com a condição de exercício físico a que foram submetidos: exercitados em esteira (grupo E) e não exercitado (grupo N). O exercício foi realizado em esteira (ET 2000 Insight) cinco dias por semana com duração diária de 30 minutos. Os grupos foram assim distribuídos (n = 6): AgN, AgE, ArN e ArE. Ao atingirem a idade de 35-45 dias de vida, os animais foram pesados, sacrificados e retidado o músculo gastrocnêmio. Este foi medido, pesado e processado para análise histológica. As imagens do músculo foram capturadas na objetiva de 100x para cálculo do diâmetro médio da fibra muscular. Os dados foram expressos na forma de média ± desvio padrão, analisados através do programa SPSS. Foram utilizados os testes de Shapiro-Wilk, ANOVA one way e teste de Tukey (p < 0,05). RESULTADOS: Não houve diferença entre os grupos, quanto ao peso corporal do animal e ao peso do músculo gastrocnêmio. No entanto, o grupo ArN apresentou diâmetro médio maior significativamente quando comparado aos dos demais grupos. CONCLUSÃO: Isto sugere que a L-arginina, em animais que não realizaram o exercício físico, promove hipertrofia muscular, enquanto que o exercício realizado não foi capaz de promover aumento do diâmetro da fibra muscular.

INTRODUCTION: Exercise and amino acid L-Arginine can promote anatomical and physiological changes in skeletal muscle. OBJECTIVE: The objective of this work was to analise the influence of L-arginine associated with the exercise in skeletal muscle fibers. METHODS: To carry out our research, 24 male Wistar rats divided into 4 groups according to the administration of Arginine and physical exercise wer used. The experimental groups were distributed as follows: Arginine-Exercise (AE, n = 6), Arginine-Not Exercised (AN, n = 6), Water-Exercise (WE, n = 6) and Water-Not Exercised (WN, n = 6). The amino acid L-Arginine was administered via orogastric intubation, at dose of 300mg/kg, daily from the 7th to 35th days of life of the animal. The exercise was performed on motorized treadmill for 30 minutes/day, 5 times a week, from 15th to 35th days of life of the animal. At the age of 35-45 days, the animals were weighed and sacrificed in order to collect the gastrocnemius muscle. The gastrocnemius muscle was measured, weighed and processed for histological analysis. The muscle's images were taken in order to calculate the mean diameter of the muscle fiber. Data were expressed as mean ± standard deviation and analyzed using SPSS. The Shapiro-Wilk, one-way ANOVA and Tukey's tests (p <0.05) were applied. RESULTS: Concerning body weight and gastrocnemius weight, there was no significant difference when all the experimental groups were compared. However, the AN group presented the highest mean diameter when compared to the other groups. CONCLUSION: This fact suggests that orogastric administration of Arginine offered to the animals that were not exercised, promotes muscle hypertrophy. On the other hand, exercise by itself did not lead to increase in mean diameter of skeletal muscle.

Effect of a Semisolid Formulation of Linum usitatissimum L. (Linseed) Oil on the Repair of Skin Wounds.

The purpose of this study was to investigate the effects of a semisolid formulation of linseed oil, SSFLO (1%, 5%, or 10%) or in natura linseed oil on skin wounds of rats. We used wound models, incisional and excisional, to evaluate, respectively, the contraction/reepithelialization of the wound and resistance to mechanical traction. The groups (n = 6) treated with SSFLO (1% or 5%) began the process of reepithelialization, to a significant extent (P < .05), on the sixth day, when compared to the petroleum jelly control group. On 14th day for the groups treated with SSFLO (1% or 5%), 100% reepithelialization was found, while in the petroleum jelly control group, this was only 33.33%. Our study showed that topical administration of SSFLO (1% or 5%) in excisional wounds allowed reepithelialization in 100% of treated animals. Therefore, a therapeutic potential of linseed oil, when used at low concentrations in the solid pharmaceutical formulations, is suggested for the process of dermal repair.

Perialveolar bacterial microbiota and bacteraemia after dental alveolitis in adult rats that had been subjected to neonatal malnutrition.

The aim of the present study was to analyse the bacteriological factors during the process of dental alveolitis, relating it to a higher incidence of bacteraemia in adult rats subjected to neonatal malnutrition. We used forty male Wistar rats, suckled by mothers fed a diet during lactation containing 17 % protein in the nourished group (N) or 8 % protein in the undernourished group (UN). After weaning, the animals were given the Labina standard diet. After 90 d, these animals underwent upper right incisor extraction and induction of alveolitis. The oral microbiota was obtained using a swab and blood culture through venous blood. These procedures were performed before the extraction, 5 min after extraction, on the 21st day after alveolitis for groups N-21 and UN-21 and on the 28th day after alveolitis for groups N-28 and UN-28. Data were expressed as means and standard deviations for parametric data, and as medians and interquartile intervals for non-parametric data. Statistical significance was considered by assuming a critical level of 5 %. Before and after extraction, lower bacterial growth was observed per colony-forming unit (CFU) in the perialveolar region of the upper right incisors of undernourished animals, while the opposite was true after alveolitis, when a larger number of CFU was observed in these animals. The percentage of positive blood cultures obtained after alveolitis was greater in the undernourished animals. The present study thus demonstrated the influence of neonatal malnutrition in the perialveolar microbiota and in the development of bacteraemia after dental alveolitis.

Morphological analysis of the enamel organ in rats treated with fluoxetine.

PURPOSE: Previous studies have evaluated the presence of serotonin in the dental epithelia and mesenchyme during odontogenesis, suggesting its participation in tooth development. MATERIALS AND METHODS: Here, we used fluoxetine, a selective serotonin re-uptake inhibitor, at a dose of 10 mg/kg, administered for 20 days during pregnancy in 12 Wistar rats to examine the influence of this drug on the development of the enamel organ of the upper first molars of rat fetuses at 17 days of intra-uterine life (i.u.l.), and at one, five and ten days postpartum. The pregnant rats were anesthetized with xylazine at 10 mg/kg and ketamine at 25 mg/kg. The fetuses were removed and beheaded; their jaws were removed, and the upper jaws were exposed. The tissues were fixed in Bouin's fixative, decalcified in 5% nitric acid for 4 - 12 h, conventionally processed for microscopy, and embedded in paraffin. Serial sections of approximately 5 mum were obtained and stained with hematoxylin and eosin, as well as periodic acid-Schiff. RESULTS AND CONCLUSION: Morphological analysis showed no structural changes in the experimental group compared to the controls, suggesting that, at the dose used, fluoxetine does not interfere with serotonin-mediated development of the enamel organ or the process of amelogenesis.

Morphological analysis of the enamel organ in rats treated with fluoxetine

Purpose: Previous studies have evaluated the presence of serotonin in the dental epithelia and mesenchyme during odontogenesis, suggesting its participation in tooth development. Materials and methods: Here, we used fluoxetine, a selective serotonin re-uptake inhibitor, at a dose of 10 mg/kg, administered for 20 days during pregnancy in 12 Wistar rats to examine the influence of this drug on the development of the enamel organ of the upper first molars of rat fetuses at 17 days of intra-uterine life (i.u.l.), and at one, five and ten days postpartum. The pregnant rats were anesthetized with xylazine at 10 mg/kg and ketamine at 25 mg/kg. The fetuses were removed and beheaded; their jaws were removed, and the upper jaws were exposed. The tissues were fixed in Bouin's fixative, decalcified in 5 percent nitric acid for 4 - 12 h, conventionally processed for microscopy, and embedded in paraffin. Serial sections of approximately 5 mm were obtained and stained with hematoxylin and eosin, as well as periodic acid-Schiff. Results and conclusion: Morphological analysis showed no structural changes in the experimental group compared to the controls, suggesting that, at the dose used, fluoxetine does not interfere with serotonin-mediated development of the enamel organ or the process of amelogenesis.

Effect of Mercurius solubilis on the bacteriological response in the alveolitis process in rats.

OBJECTIVE: The purpose of this study was to assess the bacteriological response in alveolitis in rats treated with the homeopathic medicine Merc solubilis (Merc sol.) 12 cH. METHODS: The study was randomized and observer blind. The animals were anesthetized and the upper right incisor extracted resulting in alveolitis. Animals were randomly assigned to groups (n=18/group): Water control, Alcohol control and Merc sol. 12 cH. These groups were subsequently divided into 3 subgroups (n=6/subgroup): Early Euthanasia (EE), Mid Euthanasia (ME) and Late Euthanasia (LE), killed at the 6th, 15th and 21st days respectively. The perialveolar microbiota was collected by swab in Brain Heart Infusion (BHI) for seeding and bacterioscopy. After seeding, the Petri dishes were incubated at 37 degrees C for 48 h. RESULTS: Quantitative and qualitative changes were observed in the perialveolar microbiota when the groups were compared. Water control and Alcohol control had the highest counts of pathogenic bacteria, the microbiotica of the Merc sol. group remained closer to normal. CONCLUSIONS: Merc sol. 12 cH did not reduce bacterial growth, but the microbiotica remained within the parameters of normality, obtaining the best results at 21 days after treatment.

Aspectos morfológicos das articulações temporomandibulares de interesse ao estudo da DTM / Morphologycal aspects of the temporomandibular joint of interest to the TMD study

O termo disfunções temporomandibulares é aplicado a uma gama de doenças que acometem os constituintes anatômicos e fisiológicos do sistema estomatognático, de etiologia controversa, capaz de provocar uma série de alterações morfológicas de seus componentes bem como uma vasta sintomatologia. É de importância inquestionável a necessidade, por parte dos profissionais que se empenham na prevenção e tratamento das dores orofaciais, o conhecimento da morfologia e fisiologia das estruturas relacionadas. Com o intuito de fornecer informações gerais sobre a embriologia, anatomia e alterações decorrentes das disfunções, os autores realizam revisão de literatura

Apoptose na involução do retículo estrelado de germes dentários de molares de rato / Apoptosis in the involuting stellate reticulum of rat molar tooth germs

A síntese de esmalte inicia-se na regiao correspondente ao ápice da futura cúspide do dente em formaçao, e prossegue pelas vertentes do mesmo, em direçao a alça cervical. Assim que ocorrer a deposiçao da primeira camada de esmalte, o retículo estrelado (RE) adjacente inicia um processo de involuçao, o qual, envolve uma série de eventos, tais como: diminuiçao dos espaços intercelulares, invasao vascular, reduçao do número de células e aparecimento de células do tipo macrófago. Sabe-se que, o desaparecimento de várias células embrionárias durante o desenvolvimento de tecidos e órgaos, ocorre via apoptose, e que, macrófagos sao fagócitos relacionados com a remoçao de corpos apoptóticos. Assim sendo, decidimos examinar regioes do RE em involuçao, com a finalidade de verificar se apoptose está envolvida com este processo. Para isso, utilizamos germes dentários de primeiros molares de ratos Wistar com I, 3, e 5 dias de idade, os quais, foram fixados em formaldeído para o método TUNEL; forrnol-cálcio-sacarose, para detecçao de fosfatase ácida (método da pararosanilina hexazotizada); e em glutaraldeído-formaldeído para microscopia de luz e microscopia eletrônica. Através da microscopia de luz, observamos a presença de corpos basofílicos, tanto disperses pela matriz intercelular,, como, aparentemente, no interior de células macrófagos-like do RE. A presença dê estruturas TUNEL positivas, coradas em marrom,, confirma os dados observados através da microscopia de luz indicando fragmentaçao nuclear (corpos apoptóticos). Através da técnica da pararosanilina hexazotizada,, células arredondadas apresentaram granulaçoes intensamente positivas para fosfatase ácida, indicando atividade lisosômica. Nos cortes ultrafinos, foram observadas imagens de células do RE com núcleo contendo uma massa de cromatina periférica, eletron-opaca e com forma de meia-lua (típica de apoptose). Também observamos a presença de corpos apoptóticos, de tamanho e forma variados, no citoplasma de células do retículo, o que indica que estariam sendo englobados por estas células residentes. Células do tipo macrófago do retículo estrelado apresentam no citoplasma vacúolos contendo material de eletron-opacidade variável o que sugere tanto remoçao da matriz intercelular do retículo, como também a internalizaçao e digestao de corpos apoptóticos. Estas imagens nos levam a crer que, o fenômeno de morte celular programada (apoptose) ocorre nas células do RE e está relacionada com a involuçao ...(au)