Fernanda Klein Marcondes

Determination of the estrous cycle phases of rats: some helpful considerations

The short length of the estrous cycle of rats makes them ideal for investigation of changes occurring during the reproductive cycle. The estrous cycle lasts four days and is characterized as: proestrus, estrus, metestrus and diestrus, which may be determined according to the cell types observed in the vaginal smear. Since the collection of vaginal secretion and the use of stained material generally takes some time, the aim of the present work was to provide researchers with some helpful considerations about the determination of the rat estrous cycle phases in a fast and practical way. Vaginal secretion of thirty female rats was collected every morning during a month and unstained native material was observed using the microscope without the aid of the condenser lens. Using the 10 x objective lens, it was easier to analyze the proportion among the three cellular types, which are present in the vaginal smear. Using the 40 x objective lens, it is easier to recognize each one of these cellular types. The collection of vaginal lavage from the animals, the observation of the material, in the microscope, and the determination of the estrous cycle phase of all the thirty female rats took 15-20 minutes.

Estrous cycle influences the response of female rats in the elevated plus-maze test

The aim of this study was to examine the state of anxiety and the 17beta-estradiol and progesterone levels in rats tested in the elevated plus-maze during the four phases of the estrous cycle. Male rats, female rats during each of the four phases of the estrous cycle, ovariectomized rats, and diestrus female rats treated with estradiol were tested in the elevated plus-maze between 8:00 and 10:00 a.m. Blood was collected from all rats for the determination of 17beta-estradiol and progesterone levels. Female rats in the proestrus group spent more time in the open arms than diestrus rats (P<.05). There were no significant differences in the percentage of entries into the open arms or in the number of entries into the closed arms among the phases of the estrous cycle or between males and normal or ovariectomized females. Serum estradiol levels were higher (P<.05) during proestrus compared to estrus, metestrus, and diestrus in control and plus-maze tested female rats, but there were no significant differences in progesterone levels. Treating diestrus female rats with estradiol to produce estradiol plasma concentrations similar to those seen during proestrus abolished the difference in the percentage of time spent in the open arms by proestrus and diestrus rats. Since the time spent in the open arms of the plus-maze is inversely related to anxiety, we conclude that the anxiety levels of female rats were lower in proestrus than during diestrus, and that the levels of estradiol modulate this response.

Proatherosclerotic effects of chronic stress in male rats: Altered phenylephrine sensitivity and nitric oxide synthase activity of aorta and circulating lipids

The aim of this study was to analyze the effects of chronic mild unpredictable stress (CMS) on the vasoconstrictor response and morphology of the thoracic aorta and serum lipid profiles in rats. Male Sprague–Dawley rats were submitted to CMS, which consisted of the application of different stressors for 7 days per week across 3 weeks. The rats were sacrificed 15 days after CMS expsoure. CMS induced supersensitivity to the vasoconstrictor effect of phenylephrine in endothelium-intact thoracic aortic rings without changes in aortic rings without endothelium, or pre-incubated with nitric oxide (NO) synthesis inhibitor. Rats submitted to CMS showed hypertrophy of the intima and tunica media of thoracic aorta, increased serum levels of triglycerides, total cholesterol, very low-density lipoprotein cholesterol, low-density lipoprotein cholesterol and atherogenic index, without changes in high-density lipoprotein cholesterol levels, when compared with control rats. These data indicate that CMS induces physiological and morphological changes that may contribute to the development of atherosclerosis by mechanisms related to deficiency in NO production and dyslipidemia.

Influence of anabolic steroid on anxiety levels in sedentary male rats.

The aim of this study was to evaluate the influence of nandrolone decanoate on anxiety levels in rats. Male Wistar rats were treated with nandrolone decanoate (5mg/kg, two times per week, i.m.) or vehicle (propylene glycol—0.2 ml/kg, two times per week, IM) for 6 weeks. Control rats were subject only to procedures related to their routine husbandry. By the end of 6 weeks, all groups (24–29 rats/group) were submitted to the elevated plus maze test in order to evaluate their anxiety level. Some of these animals (12– 14/group) were treated with diazepam (1 mg/kg i.p.) 30 min before the elevated plus maze test. Nandrolone decanoate significantly decreased the percentage of time spent in the open arms (1.46 ± 0.49%) compared with control (3.80 ± 0.97%) and vehicle (3.96 ± 0.85%) groups, with no difference between control and vehicle treatments. The percentage of open arm entries was also reduced in the group treated with nandrolone decanoate in comparison with the vehicle and control. No changes in the number of closed arm entries were detected. Diazepam abolished the effects of nandrolone decanoate on the percentage of time in, and entries into the open arms. The present study showed that chronic treatment with a high dose of nandrolone decanoate increased the anxiety level in male rats.

Esteróides anabólicos androgênicos e sua relação com a prática desportiva

Anabolic androgenic steroids (AAS) are a group of natural and synthetic agents formed from testosterone or one of its derivatives, whose classical therapeutic indications are associated to hipogonadism and deficiency of proteic metabolism. Acting on androgenic receptors, they modulate both the androgenic and anabolic effects. These substances vary in their ratio of anabolic:androgenic activity, but to date there is no substance that completely separates these effects, promoting only the anabolic ones. The first recorded use of AAS to improve the athletic performance occurred in 1954, in Austria, and since then this practice became widespread. Obviously, the use of AAS is out of the competitive limits, and was declared illegal by the national and international sportive governmental sectors. However, according to statistics of the International Olympic Committee, carried out in 2000, the AAS are the group of ergogenic aids most commonly used in the doping process. Studies show that supra-physiological doses of AAS can cause many adverse effects, such as atrophy of testicular tissue, hepatic and prostatic tumors, hepatocellular damage and alterations on the lipidic metabolism, on the humor and on the behavior. The aim of the present study is to compile the data regarding the AAS, involving their historical perspectives, the physiology of AAS and the existing AAS types, their therapeutic indications and the side effects resultant of the abuse of these substances and the relation between the use of AAS and the improvement of athletic performance

Brain angiotensin-converting enzymes: role of angiotensin-converting enzyme 2 in processing angiotensin II in mice.

Angiotensin (Ang)‐converting enzyme 2 (ACE2) metabolizes Ang II to the vasodilatory peptide Ang(1–7), while neprilysin (NEP) generates Ang(1–7) from Ang I. Experiments used novel Surface Enhanced Laser Desorption Ionization‐Time of Flight (SELDI‐TOF) mass spectroscopic (MS) assays to study Ang processing. Mass spectroscopy was used to measure proteolytic conversion of Ang peptide substrates to their specific peptide products. We compared ACE/ACE2 activity in plasma, brain and kidney from C57BL/6 and NEP−/− mice. Plasma or tissue extracts were incubated with Ang I or Ang II (1296 or 1045, m/z, respectively), and generated peptides were monitored with MS. Angiotensin‐converting enzyme 2 activity was detected in kidney and brain, but not in plasma. Brain ACE2 activity was highest in hypothalamus. Angiotensin‐converting enzyme 2 activity was inhibited by the specific ACE2 inhibitor, DX600 (10 μm, 99% inhibition), but not by the ACE inhibitor, captopril (10 μm). Both MS and colorimetric assays showed high ACE activity in plasma and kidney with low levels in brain. To extend these findings, ACE measurements were made in ACE overexpressing mice. Angiotensin‐converting enzyme four‐copy mice showed higher ACE activity in kidney and plasma with low levels in hypothalamus. In hypothalamus from NEP−/− mice, generation of Ang(1–7) from Ang I was decreased, suggesting a role for NEP in Ang metabolism. With Ang II as substrate, there was no difference between NEP−/− and wild‐type control mice, indicating that other enzymes may contribute to generation of Ang(1–7). The data suggest a predominant role of hypothalamic ACE2 in the processing of Ang II, in contrast to ACE, which is most active in plasma.

Influence of gender and menstrual cycle on volatile sulphur compounds production

The menstrual cycle has been pointed out as a factor influencing halitosis. However, this relationship has not yet been clarified. The aim of this study was to evaluate the influence of gender and the menstrual cycle on the production of volatile sulphur compounds (VSC) in women (n=14) across the menstrual cycle, and in men (n=17). Volunteers in good oral and general health were submitted to the evaluation of VSC, salivary flow, cortisol and anaerobic bacteria counts in saliva. Data were compared among groups by Analysis of Variance (alpha=5%). VSC was higher in the menstrual and premenstrual phases when compared with men and the follicular phase (p<0.05). Salivary flow was lower in the menstrual and premenstrual phases when compared with men and the follicular phase (p<0.05). Salivary cortisol was higher in the menstrual phase in comparison with men and the premenstrual and follicular phases (p<0.05). Total salivary protein was higher in men when compared to women (p<0.05) with no differences among menstrual phases (p>0.05). Levels of anaerobic micro-organisms, however, were not different among groups (p>0.05). In conclusion, the production of VSC is influenced by menstrual cycle and protein concentration and salivary flow might be involved in this process.

Relationship between renal and cardiovascular changes in a murine model of glucose intolerance

UNLABELLED Nutrition is an important variable which may affect the risk for renal disease. We previously showed that a high fructose diet in mice produced hypertension and sympathetic activation [8]. The purpose of this study was to determine if a fructose diet altered renal function. A high fructose diet for 12 weeks impaired glucose tolerance, but caused no change in body weight, blood glucose or plasma insulin. Impairment in renal function was documented by the almost two fold increase in urinary protein excretion ( CONTROL 6.6+/-0.6 vs. Fructose: 15.0+/-0.7 mmol protein/mmol creatinine; p<0.05) which was also accompanied by increases in urinary volume. The diet produced little change in renal histology, kidney weight or kidney weight/body weight ratio. Urinary excretion of angiotensin II/creatinine ( CONTROL 78.9+/-16.6 vs. Fructose: 80.5+/-14.2 pg/mmol) and renal angiotensin converting enzyme activity ( CONTROL 9.2+/-1.6 vs. Fructose: 7.6+/-1.0 ACE units) were not different between groups. There was a positive correlation between mean arterial pressure (r=0.7, p=0.01), blood pressure variability (BPV) (r=0.7, p=0.02), low frequency BPV component (r=0.677, p=0.03) and urinary protein excretion. Results show that consumption of a high fructose diet in mice had deleterious effects on renal function, which were correlated with cardiovascular changes.

Atrial supersensitivity to noradrenaline in stressed female rats

Stress can change the responses to catecholamines in many tissues. The aim of this study was to investigate the influence of the estrous cycle on the sensitivity of right atria to noradrenaline in female rats subjected to acute swimming stress. Female Wistar rats in proestrus, estrus, metestrus or diestrus were submitted to a 50 min-swimming session. Immediately after the exercise, the rats were killed and their right atria were mounted for isometric recording of the spontaneous beating rate. Concentration-effect curves to noradrenaline were obtained before and after the inhibition of neuronal uptake with phenoxybenzamine (10 microM) and of extraneuronal uptake with estradiol (5 microM). Acute swimming stress did not change the right atrial sensitivity to noradrenaline in rats in estrus, metestrus and diestrus. However, swimming stress produced supersensitivity to noradrenaline in proestrus (pD(2) control: 7.14 +/- 0.03 vs. pD(2) swimming: 7.55 +/- 0.04; p<0.05). This supersensitivity was still observed after uptake inhibition. When catecholamine uptake was inhibited, the concentration-effect curve to noradrenaline was shifted to the left 2.5-fold in the proestrus control group and 1.7-fold in the proestrus stress group (p<0.05). In conclusion, the estrous cycle influenced the acute stress-induced atrial supersensitivity to noradrenaline.

Nandrolone and resistance training induce heart remodeling Role of fetal genes and implications for cardiac pathophysiology

AIMS This study was conducted to assess the isolated and combined effects of nandrolone and resistance training on cardiac morphology, function, and mRNA expression of pathological cardiac hypertrophy markers. MAIN METHODS Wistar rats were randomly divided into four groups and submitted to 6 weeks of treatment with nandrolone and/or resistance training. Cardiac parameters were determined by echocardiography. Heart was analyzed for collagen infiltration. Real-time RT-PCR was used to assess the pathological cardiac hypertrophy markers. KEY FINDINGS Both resistance training and nandrolone induced cardiac hypertrophy. Nandrolone increased the cardiac collagen content, and reduced the cardiac index in non-trained and trained groups, when compared with the respective vehicle-treated groups. Nandrolone reduced the ratio of maximum early to late transmitral flow velocity in non-trained and trained groups, when compared with the respective vehicle-treated groups. Nandrolone reduced the alpha-myosin heavy chain gene expression in both non-trained and trained groups, when compared with the respective vehicle-treated groups. Training reduced the beta-myosin heavy chain gene expression in the groups treated with vehicle and nandrolone. Only the association between training and nandrolone increased the expression of the skeletal alpha-actin gene and atrial natriuretic peptide in the left ventricle. SIGNIFICANCE This study indicated that nandrolone, whether associated with resistance training or not, induces cardiac hypertrophy, which is associated with enhanced collagen content, re-expression of fetal genes the in left ventricle, and impaired diastolic and systolic function.