Avaliações Histométrica, Radiográfica e Imunológica dos Tecidos Periodontais de Ratas Ovariectomizadas com Periodontite Induzida / Histometrical, Radiographic and Immunological Evaluations of the Periodontal Tissues of Female Ovariectomized Rats With Induced Periodontits

Objetivo: A relação da osteoporose com pós-menopausa é controversa, mas pode ser um fator de risco para doença periodontal. Assim o objetivo deste projeto foi avaliar a influência da deficiência de estrógeno nos tecidos periodontais de ratas ovariectomizadas com peridontite induzida. Material e método: Quarenta ratas com 8 semanas de vida foram divididas aleatoriamente em 4 grupos: 1) Grupo controle; 2) Grupo ligadura; 3) Grupo ovariectomia; 4) Grupo ovariectomia e ligadura; sendo que todos os animais receberam dieta padrão e água à vontade. Aos 70 dias de vida os animais foram anestesiados e foi realizada a indução da doença periodontal, sendo após este procedimento aos 79 dias de vida, as ratas também foram submetidas à anestesia e à cirurgia de ovariectomia. Aos 100 dias de vida, as ratas foram sacrificadas sendo retiradas as hemimandíbulas esquerda e direita de cada rata para análises histomorfométrica e radiográfica, bem como amostras do tecido gengival para avaliar os tecidos periodontais. Resultados: Os resultados demonstraram que na análise radiográfica e histomorfométrica do osso alveolar dos primeiros molares inferiores nos grupos onde foi feita a indução da doença periodontal por ligadura, houve maior perda óssea alveolar significativamente (p<0.05). Em relação às concentrações de citocinas, os grupos que foram ovariectomizadas apresentaram concentrações maiores estatisticamente significante em relação aos demais (p<0.05). Conclusão: Assim pode-se concluir que a deficiência de estrógeno poderia contribuir para uma evolução mais rápida da perda óssea alveolar em ratas ovarietomizadas.

Aim: The relation of osteoporosis on the post-menopause is controversial; however, it can be a risk factor for the periodontal disease. Therefore, the aim of this study was to evaluate the influence of the estrogen deficiency on the periodontal tissues of female ovariectomized rat with induced periodontitis. Materials and methods: Forty rats with 8 weeks of life were randomly divided into 4 groups: 1) Control group; 2) Ligature group; 3) Ovariectomized group; 4) Ovariectomized and ligature group; that being that all the animals were treated in a standard diet and water available all time. When reaching 70 days of life, the animals were anesthetized and a periodontal disease induction was carried, after this procedure, when reaching 79 days of life, the rats were also submitted to anesthesia and went through the ovariectomy surgery. When reaching 100 days of life, the female rats were sacrificed, at when the left and right hemimandible of each rat were taken for radiographic and histomorphometric analysis, as the samples of the gingival tissue to evaluate the periodontal tissue. Results: The results highlighted that the radiographic and histomorphometric analysis of the lower alveolar bone first molars of the groups in which the induction of the periodontal disease by ligature, there was higher alveolar bone loss significantly (p<0.05). When it comes to the relation of the cytokine concentration, the groups that were ovariectomized presented significant higher concentration when compared to the others (p<0.05). Conclusion: In this way, we could conclude that the estrogen deficiency could contribute to the quicker evolution of the alveolar bone loss on female ovariectomized rats.

Oral administration of lutein attenuates ethanol-induced memory deficit in rats by restoration of acetylcholinesterase activity.

The excessive consumption of alcohol affects the central nervous system, resulting in memory and learning deficits. Lutein is a carotenoid known for its antioxidant properties, which can be able to prevent neurodegenerative diseases and cognitive deficits. In the present study, we evaluated the effect of lutein on ethanol-induced memory deficits in the object recognition task in adult rats, as well as the possible involvement of oxidative stress and cholinergic system. Wistar rats were randomly divided into two groups receiving lutein (50 mg/kg) or olive oil (1 mL/kg) by oral gavage once daily for 14 days. On day 8 each group was divided again into two groups receiving either ethanol (3 g/kg) or saline by oral gavage once daily for 7 days. After the last administration, the animals were submitted on the object recognition task 24 h later (on days 15, 16 and 17). After the behavioral test, the hippocampus and cerebral cortex were removed for the determination of oxidative stress indicators (superoxide dismutase, thiobarbituric acid reactive substances, and non-protein thiol) and acetylcholinesterase activity. Ethanol administration induced a memory deficit and increased acetylcholinesterase activity, however, it did not alter the parameters of oxidative stress, evaluated in the cortex and hippocampus. Oral administration of lutein (50 mg/kg during 14 days) attenuated memory deficit and the increase of acetylcholinesterase activity induced by ethanol. These results provide evidence that lutein is an alternative treatment for ethanol-induced memory deficit, and suggest the involvement of cholinergic system.

Nanoencapsulation of lutein and its effect on mice's declarative memory.

Lutein is a xanthophyll carotenoid widely known by its biological properties and low toxicity. When located in the brain, lutein may inhibit damage mechanisms, acting in neural cells maintenance. However, this carotenoid is very sensitive to external agents such as heat, light, pH and oxidation, besides presenting low absorption in gastrointestinal tract due its low solubility in water. Encapsulation procedures have shown promising results to increase lutein stability and bioavailability. In this work, lutein was encapsulated in polyvinylpyrrolidone (PVP) matrix by the dissolution in common solvent method. Nanoparticles were characterized in respect to morphology, water solubility, and interactions between PVP and lutein. In vivo tests were carried out in order to investigate the influence of lutein encapsulation on mice's declarative memory. Ex vivo tests were also carried out to determine if nanoparticles may cause any inflammatory process per se. Results indicated that lutein was successfully encapsulated in PVP while nanoparticles presented spherical shape and uniform size. Encapsulation was able to increase water solubility of lutein by more than 43 times, which may be attributed to the formation of soluble complexes trough hydrogen bonds between lutein hydroxyl group and PVP carbonyl group. In vivo studies showed that the administration of free lutein at 100mg·kg-1 and lutein-loaded PVP nanoparticles at 10 and 1.5mg·kg-1 significantly increased mice's object recognition index, meaning that significant lower doses of lutein were needed to achieve the same effect when lutein was encapsulated. Ex vivo studies showed that lutein-loaded nanoparticles administration did not alter inflammatory parameters in plasma, liver and brain of mice. In this sense, lutein-loaded PVP nanocapsules showed to be an advantageous alternative to increase water solubility and to improve the memory of mice without causing inflammatory damage per se.

[Blockade of AT1 receptor of Angiotensin II reduces the number of antral follicles in female rats with obesity induced by cafeteria diet]. / Bloqueio do receptor AT1 da Angiotensina II reduz o número de folículos antrais em ratas com obesidade induzida por dieta de cafeteria.

PURPOSE: To evaluate the follicular development of female Wistar rats with obesity induced by the cafeteria diet, submitted to the administration of losartan (LOS), an antagonist of the AT1 receptor of Angiotensin II. METHODS: At weaning (21 days of age), female Wistar rats were randomly divided, into two groups: control (CTL) that received standard chow and cafeteria (CAF) that received a cafeteria diet, a highly palatable and highly caloric diet. At 70 days of age, at the beginning of the reproductive age, animals of the CAF group were subdivided into two groups (n = 15/group): CAF, that received water, and CAF+LOS, that received LOS for 30 days. The CTL group also received water by gavage. At 100 days of age, the animals were euthanized and body weight (BW) as well as the retroperitoneal, perigonadal and subcutaneous fat weights were analyzed. The right ovaries were isolated for counting the number of primary, secondary, antral and mature follicles. Plasma levels of FSH, LH, prolactin and progesterone hormones were analyzed. The results were expressed as mean ± standard error of the mean. Data were analyzed statistically by one-way ANOVA followed by the Newman-Keuls post-test (p < 0.05). RESULTS: BW and fat weight, as well as the number of antral follicles, were higher in the CAF group compared to the CTL group. However, FSH and LH levels were lower in CAF animals compared to CTL animals. LOS administration attenuated the reduction of FSH and LH levels. Progesterone and PRL levels were similar among groups. CONCLUSION: LOS could improve follicular development in obese females and could be used as an adjunctive drug in the treatment of infertility associated with obesity.

Bloqueio do receptor AT1 da Angiotensina II reduz o número de folículos antrais em ratas com obesidade induzida por dieta de cafeteria / Blockade of AT1 receptor of Angiotensin II reduces the number of antral follicles in female rats with obesity induced by cafeteria diet

OBJETIVO: Avaliar o desenvolvimento folicular em ratas Wistar com obesidade induzida por dieta de cafeteria (DCAF) submetidas à administração de losartan (LOS), um antagonista do receptor AT1 da Angiotensina II. MÉTODOS: Aos 21 dias de vida, as ratas foram separadas aleatoriamente em dois grupos: controle (CTL), que recebeu ração padrão, e cafeteria (CAF), que recebeu a DCAF, altamente palatável e calórica. Aos 70 dias de vida, início da idade reprodutiva, animais do grupo CAF foram subdivididos em dois grupos (n=15/grupo): CAF, que recebeu água, e CAF+LOS, que recebeu 30 mg/kg de peso corporal (PC) de LOS por gavagem durante 30 dias. O grupo CTL também recebeu água por gavagem. Aos 100 dias de vida foi realizada a eutanásia dos animais e o PC e das gorduras retroperitoneal, perigonadal e subcutânea foi avaliado. Os ovários direitos foram retirados para contagem do número dos diferentes tipos de folículos ovarianos. As concentrações plasmáticas dos hormônios folículo-estimulantes (FSH), luteinizante (LH), prolactina (PRL) e progesterona foram avaliadas. Os resultados foram expressos como média±erro padrão da média. Para análise estatística, foi utilizado one-way ANOVA, seguido pelo pós-teste de Newman-Keuls (p<0,05). RESULTADOS: O PC e das gorduras, assim como o número de folículos antrais, foi elevado no grupo CAF em relação ao CTL. Todavia, as concentrações de FSH e LH foram mais baixas entre os animais CAF. A administração de LOS reduziu o PC e das gorduras retroperitoneal e subcutânea, bem como o número de folículos antrais. O tratamento com LOS atenuou a redução das concentrações de FSH e de LH. As concentrações de progesterona e PRL foram semelhantes entre os grupos estudados. CONCLUSÃO: O uso de LOS pode favorecer o desenvolvimento folicular em fêmeas obesas e pode possibilitar sua utilização como fármaco coadjuvante no tratamento da infertilidade associada à obesidade. .

PURPOSE: To evaluate the follicular development of female Wistar rats with obesity induced by the cafeteria diet, submitted to the administration of losartan (LOS), an antagonist of the AT1 receptor of Angiotensin II. METHODS: At weaning (21 days of age), female Wistar rats were randomly divided, into two groups: control (CTL) that received standard chow and cafeteria (CAF) that received a cafeteria diet, a highly palatable and highly caloric diet. At 70 days of age, at the beginning of the reproductive age, animals of the CAF group were subdivided into two groups (n=15/group): CAF, that received water, and CAF+LOS, that received LOS for 30 days. The CTL group also received water by gavage. At 100 days of age, the animals were euthanized and body weight (BW) as well as the retroperitoneal, perigonadal and subcutaneous fat weights were analyzed. The right ovaries were isolated for counting the number of primary, secondary, antral and mature follicles. Plasma levels of FSH, LH, prolactin and progesterone hormones were analyzed. The results were expressed as mean±standard error of the mean. Data were analyzed statistically by one-way ANOVA followed by the Newman-Keuls post-test (p<0.05). RESULTS: BW and fat weight, as well as the number of antral follicles, were higher in the CAF group compared to the CTL group. However, FSH and LH levels were lower in CAF animals compared to CTL animals. LOS administration attenuated the reduction of FSH and LH levels. Progesterone and PRL levels were similar among groups. CONCLUSION: LOS could improve follicular development in obese females and could be used as an adjunctive drug in the treatment of infertility associated with obesity. .

Sex differences in brain cholinergic activity in MSG-obese rats submitted to exercise.

Obesity is an epidemic disease most commonly caused by a combination of increased energy intake and lack of physical activity. The cholinergic system has been shown to be involved in the regulation of food intake and energy expenditure. Moreover, physical exercise promotes a reduction of fat pads and body mass by increasing energy expenditure, but also influences the cholinergic system. The aim of this study is to evaluate the interaction between physical exercise (swimming) and central cholinergic activity in rats treated with monosodium glutamate (MSG, a model for obesity) during infancy. Our results show that MSG treatment is able to induce obesity in male and female rats. Specifically, MSG-treated rats presented a reduced body mass and nasoanal length, and increased perigonadal and retroperitoneal fat pads in relation to the body mass. Physical exercise was able to reduce body mass in both male and female rats, but did not change the fat pads in MSG-treated rats. Increased food intake was only seen in MSG-treated females submitted to exercise. Cholinergic activity was increased in the cortex of MSG-treated females and physical exercise was able to reduce this activity. Thalamic cholinergic activity was higher in sedentary MSG-treated females and exercised MSG-treated males. Hypothalamic cholinergic activity was higher in male and female MSG-treated rats, and was not reduced by exercise in the 2 sexes. Taken together, these results show that MSG treatment and physical exercise have different effects in the cholinergic activity of males and females.

Estradiol and progesterone modulation of angiotensin II receptors in the arcuate nucleus of ovariectomized and lactating rats.

The expression of angiotensin II (Ang II) receptors in the brain is modulated by estradiol and progesterone. Considering that Ang II plays a critical role in controlling prolactin secretion and that neurons in the arcuate nucleus (ARC) are the main regulator of this function, the present study aimed to evaluate ARC Ang II receptor binding in 2 experimental models with different estradiol and progesterone plasma levels. Animals were divided into 4 groups: ovariectomy (OVX) plus oil vehicle, OVX plus estradiol and progesterone replacement, lactating rats on day 7 postpartum, and lactating rats on day 20. Animals were killed by decapitation, and the brains were removed. Ang II receptors were quantified by autoradiography in ARC. Trunk blood samples were collected, and plasma estradiol and progesterone were measured by radioimmunoassay. Treatment of OVX rats with estradiol and progesterone increased Ang II receptor binding when compared to OVX vehicle-treated animals. Plasma estradiol (r = +0.77) and progesterone (r = +0.87) were highly correlated with Ang II receptors in ovariectomized animals. Lactating rats (day 20) showed a significant decrease in Ang II receptor binding and plasma progesterone when compared to lactating rats (day 7), however, no difference was seen in plasma estradiol. Plasma levels of progesterone (r = +0.81), but not estradiol (r = +0.32), were highly correlated with Ang II receptors in lactating rats. In conclusion, present results show that ARC Ang II receptors decreases on day 20 of lactation compared to day 7 and are highly correlated with plasma progesterone, indicating a pivotal role for progesterone in this regulation.

Angiotensin II receptors are upregulated by estradiol and progesterone in the locus coeruleus, median preoptic nucleus and subfornical organ of ovariectomized rats.

Angiotensin II (Ang II) receptors in specific brain areas and in the anterior pituitary are controlled by reproductive hormones. Since Ang II also plays a role in controlling reproductive functions, such as luteinizing hormone and prolactin secretion, the objective of the present study was to evaluate the regulation of Ang II receptors by estradiol (E(2)) and progesterone (P) in areas of the brain involved in homeostatic and reproductive functions, such as the locus coeruleus (LC), median preoptic nucleus (MnPO) and subfornical organ (SFO). Adult female rats were ovariectomized under anesthesia and divided into 2 groups after 2 weeks: OVX plus E(2)/P replacement (OVXE(2)P) and OVX plus oil vehicle (OVX). E(2) was injected for 3 consecutive days followed by an injection of P on the 4th day. Animals were killed by decapitation and the brains were removed and frozen. Consecutive coronal brain sections were cut in a cryostat and Ang II receptors were quantified by autoradiography in the MnPO, LC and SFO. Treatment of OVX rats with E(2) and P induced a significant increase in the Ang II receptor binding (fmol/mg protein) in the MnPO (OVX: 4.48 +/- 0.58 and OVXE(2)P: 9.89 +/- 1.65), LC (OVX: 2.72 +/- 0.37 and OVXE(2)P: 8.03 +/- 0.9) and SFO (OVX: 5.45 +/- 0.66 and OVXE(2)P: 10.73 +/- 1.79) compared to OVX animals treated with the vehicle, P < 0.05. In conclusion, these results show that Ang II receptors are upregulated by E(2) and P in the LC, MnPO and SFO of ovariectomized rats.

Angiotensin II receptors in the arcuate nucleus mediate stress-induced reduction of prolactin secretion in steroid-primed ovariectomized and lactating rats.

Angiotensin II (Ang II) is a peptide that exerts an inhibitory effect upon pituitary prolactin (PRL) release through the hypothalamic arcuate nucleus (ARC). Since both PRL and Ang II are known to be affected by stress, the experiments reported here were conducted to investigate the possible participation of Ang II in the stress-induced response of PRL in situations in which pre-stress PRL levels are high, as during the PRL surge induced by estradiol (E(2)) and progesterone (P) in ovariectomized rats (OVXE(2)P) and lactating females on day 7 post-partum. Adult female rats were stereotactically implanted with bilateral guide-cannulae in the ARC; 3 days later, they were microinjected with saline or losartan and, after a 15-min interval, they were submitted to stress by ether inhalation during 1 min. Five minutes after stress, trunk blood samples were collected. Plasma PRL was measured by radioimmunoassay (RIA). In OVXE(2)P and lactating rats, a significant reduction in PRL levels was detected after stress compared to non-stressed animals. The microinjection of losartan in the ARC before stress blocked the reduction of PRL in both OVXE(2)P and lactating females. In conclusion, the stress-induced reduction of plasma PRL in OVXE(2)P and lactating rats is mediated by Ang II through AT(1) receptors in the ARC.