Hypercapnic ventilatory response of anesthetized female rats subjected to neonatal maternal separation: Insight into the origins of panic attacks?

Neonatal maternal separation (NMS) is a form of stress that interferes with the regulation of the stress response, an effect that predisposes to the emergence of panic and anxiety related disorders. We previously showed that at adulthood, awake female (but not male) rats subjected to NMS show a hypercapnic ventilatory response (HCVR; 5% CO(2)) that is 63% greater than controls (Genest et al., 2007). To understand the mechanisms underlying the sex-specific effects of NMS on the ventilatory response to CO(2), we used two different anesthetized female rat preparations to assess central CO(2) chemosensitivity and contribution of sensory afferents (stretch receptors and peripheral chemoreceptors) that influence the HCVR. Data show that anesthesia eliminated the respiratory phenotype observed previously in awake females and CO(2) chemosensitivity did not differ between groups. Finally, the assessment of the ovarian hormone levels across the oestrus cycle failed to reveal significant differences between groups. Since anesthesia did not affect the manifestation of NMS-related respiratory dysfunction in males (including the hypercapnic ventilatory response) (Kinkead et al., 2005; Dumont and Kinkead, 2010), we propose that the panic or anxiety induced by CO(2) during wakefulness is responsible for enhancement of the HCVR in NMS females. (C) 2011 Elsevier B.V. All rights reserved.

OVARIAN HISTOLOGY and FOLLICULAR SCORE IN FEMALE RATS TREATED WITH NANDROLONE DECANOATE and SUBMITTED TO PHYSICAL EFFORT

The study was conducted to analyze the histology of the ovaries of adults rats treated with steroids, and submitted or not to physical effort. The control group consisted of females submitted to physical effort and sedentary females, both of which received a physiological solution of 0.9% saline. Treated females, sedentary or not, received 6 mg/kg of body weight of nandrolone decanoate. The steroid and physiological solution were administered intraperitoneally, with a single injection per week for 4 consecutive weeks. The applied physical effort was swimming (20 minutes daily, 5 days/week, for the 4 weeks of treatment). Serial sections (5 mu m) of ovaries were prepared for histological evaluation and follicular score. The weight of ovaries and hypophysis, the number of antral and atretic follicles, and the area of corpus luteum were all affected by the steroids. In the ovaries of the control groups, well-developed corpus luteum was observed. In the treated groups, the cortical stroma was occupied by ovarian interstitial tissue. The females treated with steroids presented estral acyclicity. The use of nandrolone decanoate, whether associated with physical effort or not, affected the morphological pattern of the ovaries.

Time course of training-induced microcirculatory changes and of vegf expression in skeletal muscles of spontaneously hypertensive female rats

Exercise-induced vessel changes modulate arterial pressure (AP) in male spontaneously hypertensive rats (SHR). Vascular endothelial growth factor (VEGF) is important for angiogenesis of skeletal muscle. The present study evaluated the time course of VEGF and angiogenesis after short- and long-term exercise training of female SHR and Wistar Kyoto (WKY) rats, 8-9 weeks (200-250 g). Rats were allocated to daily training or remained sedentary for 3 days (N = 23) or 13 weeks (N = 23). After training, the carotid artery was catheterized for AP measurements. Locomotor (tibialis anterior and gracilis) and non-locomotor skeletal muscles (temporalis) were harvested and prepared for histologic and protein expression analyses. Training increased treadmill performance by all groups (SHR = 28%, WKY = 64%, 3 days) and (SHR = 141%, WKY = 122%, 13 weeks). SHR had higher values of AP than WKY (174 ± 4 vs 111 ± 2 mmHg) that were not altered by training. Three days of running increased VEGF expression (SHR = 28%, WKY = 36%) simultaneously with an increase in capillary-to-fiber ratio in gracilis muscle (SHR = 19%, WKY = 15%). In contrast, 13 weeks of training increased gracilis capillary-to-fiber ratio (SHR = 18%, WKY = 19%), without simultaneous changes in VEGF expression. Training did not change VEGF expression and capillarity of temporalis muscle. We conclude that training stimulates time- and tissue-dependent VEGF protein expression, independent of pressure levels. VEGF triggers angiogenesis in locomotor skeletal muscle shortly after the exercise starts, but is not involved in the maintenance of capillarity after long-term exercise in female rats.

Exercise training attenuates acute hyperalgesia in streptozotocin-induced diabetic female rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Levels of DNA damage in blood leukocyte samples from non-diabetic and diabetic female rats and their fetuses exposed to air or cigarette smoke

dThe objective of the present study was to evaluate DNA damage level in blood leukocytes from diabetic and non-diabetic female Wistar rats exposed to air or to cigarette smoke, and to correlate the findings with levels of DNA damage detected in blood leukocyte samples from their fetuses. A total of 20 rats were distributed into four experimental groups: non-diabetic (control; G1) and diabetic exposed to filtered air (G2): non-diabetic (G3) and diabetic (G4) exposed to cigarette smoke. Rats placed into whole-body exposure chambers were exposed for 30 min to filtered air (control) or to tobacco smoke generated from 10 cigarettes, twice a day, for 2 months. Diabetes was induced by a pancreatic beta-cytotoxic agent, streptozotocin (40 mg/kg b.w.). At day 21 of pregnancy, each rat was anesthetized and humanely killed to obtain maternal and fetal blood samples for genotoxicity analysis using the alkaline comet assay. G2, G3 and G4 dams presented higher DNA damage values in tail moment and tail length as compared to G1 group. There was a significant positive correlation between DNA damage levels in blood leukocyte samples from G2 and G3 groups (tail moment); G3 and G4 groups (tail length) and G3 group (tail intensity) and their fetuses. Thus, this study showed the association of severe diabetes and tobacco cigarette smoke exposure did not exacerbate levels of maternal and fetal DNA damages related with only diabetes or cigarette smoke exposure. Based on the results obtained and taking into account other published data, maternal diabetes requires rigid clinical control and public health and education campaigns should be increased to encourage individuals, especially pregnant women, to stop smoking. (C) 2008 Elsevier B.V. All rights reserved.

Effects of synbiotic-based Bifidobacterium animalis in female rats experimentally infected with Toxoplasma gondii

The aim of this study was to assess the effects of a synbiotic composed of Bifidobacterium animalis and fructooligosaccharides on female rats infected with Toxoplasma gondii. Female Wistar rats, treated or not with dexamethasone, were daily supplemented with synbiotics for 21 days. After 15 days of supplementation, the rats were orally infected with 10(4) T. gondii bradyzoites. Blood samples were collected to measure the levels of IFN-gamma, IL-10 and T. gondii antibodies. All synbiotic-supplemented rats survived until the end of the experiment; however, non-supplemented dexamethasone-treated rats died between the fifth and the eighth days after T. gondii infection. Dexamethasone-treated rats supplemented with synbiotics (P < 0.05) were capable of synthesizing IFN-gamma, and this immunological response was essential to ensure their survival. In addition, brain cysts were found in one rat not supplemented with synbiotics. Results suggest that the synbiotic composed of B. animalis and fructooligosaccharides may be beneficial to toxoplasmosis control. (C) 2010 Elsevier Ltd. All rights reserved.

Detection of Toxoplasma gondii in the milk of experimentally infected Wistar female rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Oxytocin promotes bone formation during the alveolar healing process in old acyclic female rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The influence of loss of bone mass on induced periodontal disease: A radiographic and densitometric study of female rats

Background: Changes in mineral density in the mandibular and femoral bones (BMD) after estrogen deficiency caused by ovariectomy (OVX) and the influence of these changes on induced periodontal disease were evaluated in female rats.Methods: Forty-eight female Holtzman rats (90 days old) were randomly divided into five groups: 0: control (N = 9); 1: SHAM without induced periodontal disease (N = 11); 2: SHAM with induced disease (N = 10); 3: OVX without induced disease (N = 9); and 4: OVX with induced disease (N = 9). In groups 2 and 4, the first lower molars were tied with ligatures for 30 days 120 days after surgery. After 5 months the animals were sacrificed to measure global mineral density (BMD) and that of the sub-regions of the mandible and femur by dual energy x-ray absorptiometry (DXA). The extent of vertical bone loss was evaluated with digital radiography by measuring the distance from the bone crest to the cemento-enamel junction at the mesial of the first lower molar.Results: Results of the femur (Kruskal-Wallis test) showed a significant difference (P < 0.001) between the groups SHAM and OVX in bone density values for all regions. Comparison between the groups in relation to the BMD of the mandible, both in the sub-regions and global revealed no differences (P < 0.05). The vertical bone loss measured for the groups with induced disease was similar (P= 0.713).Conclusions: Differences between the groups were found in the bone mineral density BMD of the femur but not of the mandible. OVX had no influence on induced periodontal disease.

Influence of estrogen deficiency and its treatment with alendronate and estrogen on bone density around osseointegrated implants: radiographic study in female rats

Objective. This study evaluated the influence of estrogen deficiency and its treatment on bone density around integrated implants.Study design. Implants were placed in female rat tibiae. The animals were assigned to 5 groups: control, sham, ovariectomy, estrogen, and alendronate. The control group was humanely killed to confirm integration of the implant. The others were submitted to ovariectomy or sham surgery. Bone density was measured by digital radiographs at 6 points on sides of the implant.Results. The analysis of radiographic bone density revealed estrogen privation had a negative impact only in the cancellous bone. The estrogen group differed significantly ( P <.05) from the ovariectomy and alendronate groups. The alendronate group presented the highest density for all evaluated regions.Conclusion. Ovariectomy caused a decrease in the radiographic bone density in the cancellous region. Estrogen replacement therapy and alendronate were effective treatments in preventing bone mass loss around integrated implants.

Immunohistochemical detection of estrogen receptor beta in alveolar bone cells of estradiol-treated female rats: possible direct action of estrogen on osteoclast life span

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Differential vascular adaptive response to stress exposure in male and female rats: Role of gonadal hormones and endothelial cells

Although there are reports concerning a vascular adaptive response to stress in males, this is not yet defined in females. The aim of this study was to delineate functional gender differences in the rat vascular adaptive response to stress and to determine the ability of sex hormones to modulate the stress-induced vascular adaptive response. Responses to noradrenaline were evaluated in aortas, with and without endothelium, from intact, gonadectomized and gonadectomized-hormone-replaced males and females submitted or not to stress (2-h immobilization). Reactivity of the aorta of stressed and non-stressed intact males and females (n = 6-14 per group) was also examined in the presence of L-NAME or indomethacin. Stress decreased and gonadectomy increased maximal responses to noradrenaline in aortas with intact endothelium from both genders. Stress also reduced noradrenaline potency in males. In females, but not males, stress decreased the gonadectomy-induced noradrenaline hyper-reactivity to near that of intact non-stressed rats. Hormone replacement restored the gonadectomy-induced impaired vascular adaptive response to stress. L-NAME, but not indomethacin, abolished the stress-induced decrease in aorta reactivity of males and females. None of the procedures altered reactivity of aortas denuded of endothelium. Conclusion: Stress-induced vascular adaptive responses show gender differences. The magnitude of the adaptive response is dependent on testicular hormones and involves endothelial nitric oxide-system hyperactivity.

In utero and lactational exposure to fenvalerate disrupts reproductive function in female rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)