RESUMO
In brief: Congenital ZIKV infection promotes alarming effects on male offspring's reproductive biology. This study showed the presence of the ZIKV antigen in the testis parenchyma, decreased testosterone levels, and sperm abnormalities in male offspring born to infected mothers. Abstract: Infection with ZIKV during pregnancy is associated with fetal developmental problems. Although neurological issues are being explored more in experimental studies, limited research has focused on the reproductive health consequences for offspring born to infected mothers. In this context, this study aimed to assess the impact of ZIKV infection during pregnancy on the testes and sperm of adult male offspring. Female mice were intraperitoneally inoculated with a Brazil strain of ZIKV during the 5.5th day of embryonic gestation. The offspring were evaluated 12 weeks after birth to analyze cellular and molecular changes in the testes and sperm. A novel approach combining variable-angle spectroscopic ellipsometry and machine learning modeling was also introduced for sperm sample analysis. The study revealed the presence of ZIKV protein in the testis parenchyma of adult male offspring born to infected mothers. It was shown that the testes exhibited altered steroidogenesis and inflammatory mediators, in addition to significant issues with spermiogenesis that resulted in sperm with DNA fragmentation, head defects, and protamination failure. Additionally, sperm dielectric properties and artificial intelligence showed potential for rapid identification and classification of sperm samples from infected mice. These findings provide crucial insights into the reproductive risks for men born from ZIKV-infected pregnant women.
Assuntos
Complicações Infecciosas na Gravidez , Infecção por Zika virus , Zika virus , Adulto , Masculino , Humanos , Feminino , Gravidez , Animais , Camundongos , Infecção por Zika virus/complicações , Inteligência Artificial , Sêmen , BiologiaRESUMO
AIM: To evaluate the influence of an experimental solution of cobalt-doped F18 bioactive glass (F18Co) on tissue repair following regenerative endodontic procedure (REP) in rat molars. METHODOLOGY: The F18Co solution was prepared at a ratio of 1:5 F18Co powder to distilled water. The right or left upper first molars of 12 Wistar rats were used, where the pulps were exposed, removed, and irrigated with 2.5% sodium hypochlorite (NaOCl), followed by 17% ethylenediaminetetraacetic acid (EDTA) (5 min each). Subsequently, the molars were divided into two groups (n = 6): REP-SS and REP-F18Co, where they received a final irrigation (5 min) with saline solution (SS) or F18Co solution, respectively. Then, intracanal bleeding was induced, and the tooth was sealed. Untreated molars were used as controls (n = 3). At 21 days, the rats were euthanized, and the specimens were processed for analysis of mineralized tissue and soft tissue formation inside the root canal using haematoxylin-eosin. The presence and maturation of collagen were evaluated by Masson's trichrome and picrosirius red staining. Immunolabelling analyses of proliferating cell nuclear antigen (PCNA) and osteocalcin (OCN) were performed. The data were submitted to the Mann-Whitney U-test (p < .05). RESULTS: There was a similar formation of mineralized tissue in thickness and length in REP-SS and REP-F18Co groups (p > .05). Regarding the presence of newly formed soft tissue, most specimens of the REP-F18Co had tissue formation up to the cervical third of the canal, whilst the REP-SS specimens showed formation up to the middle third (p < .05), and there was higher maturation of collagen in REP-F18Co (p < .05). The number of PCNA-positive cells found in the apical third of the root canal was significantly higher in the F18Co group, as well as the OCN immunolabelling, which was severe in most specimens of REP-F18Co, and low in most specimens of REP-SS. CONCLUSION: The final irrigation with F18Co bioactive glass solution in REP did not influence mineralized tissue formation but induced soft tissue formation inside the root canals, with higher collagen maturation, and an increase in PCNA-positive cells and OCN immunolabelling.
Assuntos
Cerâmica , Cavidade Pulpar , Endodontia Regenerativa , Animais , Ratos , Preparo de Canal Radicular/métodos , Osteocalcina , Antígeno Nuclear de Célula em Proliferação , Ratos Wistar , Ácido Edético , Colágeno , Proliferação de Células , Irrigantes do Canal Radicular/farmacologia , Hipoclorito de Sódio/farmacologiaRESUMO
AIM: To analyse the influence of ethylenediaminetetraacetic acid (EDTA) on the repair process in immature rat molars after a regenerative endodontic procedure (REP). METHODOLOGY: The lower first molars of 12 4-week-old Wistar rats underwent pulpectomy in the mesial root and were divided into the following groups: sodium hypochlorite (NaOCl; n = 6) - the mesial canals were irrigated with 2.5% NaOCl for 5 min, and NaOCl-EDTA (n = 6) - the canals were irrigated with 2.5% NaOCl, followed by 17% EDTA for 5 min each. After evoking bleeding using a size 10 K-file, the cavities were sealed. Three molars on the untreated side were randomly used as control (control-15 d; n = 3), and three molars from the other three rats untreated were used as immediate control (n = 3). After 15 days (NaOCl, NaOCl-EDTA and control-15 d groups) or immediately (control-immediate), the animals were euthanized, and the teeth were subjected to histologic evaluation of tissue regeneration and presence of collagen fibres. Mann-Whitney U-test was used (p < .05). RESULTS: The experimental groups had newly formed cementum-like tissue and increased root length and thickness. Half of the specimens in NaOCl-EDTA group showed apical foramen closure, whilst the NaOCl group had partial apical closure. The experimental groups showed inflammatory infiltrate extending mainly to the medium third of the root canal. These parameters were similar between experimental groups (p > .05). Newly formed connective tissue in the pulp space was significantly higher in the NaOCl-EDTA group than in NaOCl group (p < .05). Regarding the collagen fibres, the NaOCl-EDTA group had more collagen fibres in the root tip, but there was no significant difference compared to NaOCl group, and both groups showed greater amount of immature fibres in this area; in the centre of the apical third of root canal, there was equivalence between mature and immature fibres from both groups (p > .05). CONCLUSIONS: Ethylenediaminetetraacetic acid irrigation improved newly formed intracanal connective tissue after REP in immature molars of rats; however, EDTA did not influence cementum-like tissue formation, apical closure, inflammatory infiltrate and maturation of collagen fibres.
Assuntos
Colágeno , Animais , Ratos , Ácido Edético/farmacologia , Ácido Edético/uso terapêutico , Ratos WistarRESUMO
This study aimed to evaluate the physical exercise-induced neuronal activation in brain nuclei controlling thermoregulatory responses in hypertensive and normotensive rats. Sixteen-week-old male normotensive Wistar rats (NWRs) and spontaneously hypertensive rats (SHRs) were implanted with an abdominal temperature sensor. After recovery, the animals were subjected to a constant-speed treadmill running (at 60% of the maximum aerobic speed) for 30 min at 25 °C. Core (Tcore) and tail-skin (Tskin) temperatures were measured every minute during exercise. Ninety minutes after the exercise, the rats were euthanized, and their brains were collected to determine the c-Fos protein expression in the following areas that modulate thermoregulatory responses: medial preoptic area (mPOA), paraventricular hypothalamic nucleus (PVN), and supraoptic nucleus (SON). During treadmill running, the SHR group exhibited a greater increase in Tcore and an augmented threshold for cutaneous heat loss relative to the NWR group. In addition, the SHRs showed reduced neuronal activation in the mPOA (< 49.7%) and PVN (< 44.2%), but not in the SON. The lower exercise-induced activation in the mPOA and PVN in hypertensive rats was strongly related to the delayed onset of cutaneous heat loss. We conclude that the enhanced exercise-induced hyperthermia in hypertensive rats can be partially explained by a delayed cutaneous heat loss, which is, in turn, associated with reduced activation of brain areas modulating thermoregulatory responses.
Assuntos
Regulação da Temperatura Corporal , Hipertensão/fisiopatologia , Hipotálamo/fisiopatologia , Corrida , Animais , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos WistarRESUMO
The significant increase in glyphosate-based herbicide (GBH) use raises concerns about residues in the environment and food, potentially jeopardizing human health. The involvement of GBHs in the increased incidence of thyroid disorders is speculated, since glyphosate has been linked to an increased risk of thyroid disease in farmers. In this sense, this study aims to investigate the potential effects of low levels of GBH exposure (0, 0.5 or 5 mg/kg) from weaning (postnatal day PND23) to adult life (PND60 and PND90) in male Wistar rats on hypothalamic-pituitary-thyroid (HPT) axis function. The serum levels of T4 were increased. The hypothalamus showed reduced expression of Dio2, Thra1, and Thra2. The pituitary showed reduced expression of Mct8 and Dio2 and increased expression of Thra1. The thyroid showed increased expression of Tshr and Thra1. The heart showed increased expression of Mct8 and Myh6. The liver showed reduced expression of Mct8 and Thra2 and increased expression of Thra1. In thyroid morphometry, a decrease in both follicular diameter and area and decreased follicular and colloid diameters and areas were observed. These results suggested that GBH may affect several steps of HPT axis regulation at the transcriptional level in an age-dependent manner and alter the morphometric parameters of the thyroid gland and TH synthesis, with potential repercussions in the TH-target organs.
Assuntos
Herbicidas , Glândula Tireoide , Ratos , Humanos , Animais , Masculino , Herbicidas/metabolismo , Ratos Wistar , Hipófise , GlifosatoRESUMO
It is well-established that the hypothalamic-pituitary-gonadal (HPG) axis is suppressed due to negative energy balance. However, less information is available on whether kisspeptin neuronal activity contributes to fasting-induced responses. In the present study, female and male mice were fasted for 24 hours or provided food ad libitum (fed group) to determine whether acute fasting is sufficient to modulate kisspeptin neuronal activity. In female mice, fasting attenuated luteinizing hormone (LH) and prolactin (PRL) serum levels and increased follicle-stimulating hormone levels compared with the fed group. In contrast, fasting did not affect gonadotropin or PRL secretion in male mice. By measuring genes related to LH pulse generation in micropunches obtained from the arcuate nucleus of the hypothalamus (ARH), we observed that fasting reduced Kiss1 mRNA levels in female and male mice. In contrast, Pdyn expression was upregulated only in fasted female mice, whereas no changes in the Tac2 mRNA levels were observed in both sexes. Interestingly, the frequency and amplitude of the GABAergic postsynaptic currents recorded from ARH kisspeptin neurons (ARHKisspeptin) were reduced in 24-hour fasted female mice but not in males. Additionally, neuropeptide Y induced a hyperpolarization in the resting membrane potential of ARHKisspeptin neurons of fed female mice but not in males. Thus, the response of ARHKisspeptin neurons to fasting is sexually dependent with a female bias, associated with changes in gonadotropins and PRL secretion. Our findings suggest that GABAergic transmission to ARHKisspeptin neurons modulates the activity of the HPG axis during situations of negative energy balance.
Assuntos
Kisspeptinas , Hormônio Luteinizante , Camundongos , Feminino , Masculino , Animais , Kisspeptinas/metabolismo , Hormônio Luteinizante/metabolismo , Transmissão Sináptica , Neurônios/metabolismo , Núcleo Arqueado do Hipotálamo/metabolismo , Jejum/metabolismo , RNA Mensageiro/metabolismoRESUMO
We evaluated whether the administration of kisspeptin-10 (Kp10) is capable of restoring gonadal function in hypothyroid male rats. Hypothyroidism was induced with 6-propyl-2-thiouracil (PTU) for three months. In the last month, half of the hypothyroid animals were treated with Kp10. Hypothyroidism reduced testicular and sex gland mass, decreased the proliferation of the seminiferous epithelium, and compromised sperm morphology, motility, and vigor. A decrease in plasma LH and testosterone levels and an increase in prolactin secretion were observed in the hypothyroid rats. Hypothyroidism reduced Kiss1 and Kiss1r protein and gene expression and Star and Cyp11a1 mRNA levels in the testis. Furthermore, it reduced Lhb, Prl, and Drd2 and increased Tshb and Gnrhr expression in the pituitary. In the hypothalamus, hypothyroidism increased Pdyn and Kiss1r while reducing Gnrh1. Kp10 treatment in hypothyroid rats restored testicular and seminal vesicle morphology, improved sperm morphology and motility, reversed high prolactin levels, and increased LH and testosterone levels. In addition, Kp10 increased testicular expression of Kiss1, Kiss1r, Fshr, and Nr5a1 and pituitary Kiss1 expression. Our findings describe the inhibitory effects of hypothyroidism on the male gonadal axis and sperm quality and demonstrate that Kp10 treatment reverses high prolactin levels and improves gonadal function and sperm quality in hypothyroid rats.
Assuntos
Hipotireoidismo , Kisspeptinas , Ratos , Animais , Masculino , Kisspeptinas/farmacologia , Kisspeptinas/metabolismo , Prolactina/metabolismo , Hormônio Luteinizante , Receptores de Kisspeptina-1/metabolismo , Sêmen/metabolismo , Hipotireoidismo/metabolismo , Testículo/metabolismo , TestosteronaRESUMO
Alterations of circulating and placental levels of kisspeptin have been associated with gestational diseases. However, there are still no studies on the placental and decidual expression of Kiss1 and its receptor Kiss1r in maternal hypothyroidism, which is the aim of this work. We demonstrate that the fetoplacental restriction caused by hypothyroidism in rats is associated with a reduction in the Kiss1r expression and reduced Kiss1 and Kiss1r mRNA levels in the decidua and/or placenta. This demonstrate that fetoplacental restriction in hypothyroid rats is linked with a suppression of the kisspeptin/Kiss1r system at the maternal-fetal interface.
Assuntos
Hipotireoidismo , Kisspeptinas , Animais , Feminino , Kisspeptinas/genética , Kisspeptinas/metabolismo , Placenta/metabolismo , Gravidez , Ratos , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Kisspeptina-1/genética , Receptores de Kisspeptina-1/metabolismoRESUMO
Maternal hypothyroidism is associated with fetal growth restriction, placental dysfunction, and reduced kisspeptin/Kiss1R at the maternal-fetal interface. Kisspeptin affects trophoblastic migration and has antioxidant and immunomodulatory activities. This study aimed to evaluate the therapeutic potential of kisspeptin in the fetal-placental dysfunction of hypothyroid Wistar rats. Hypothyroidism was induced by daily administration of propylthiouracil. Kisspeptin-10 (Kp-10) treatment was performed every other day or daily beginning on day 8 of gestation. Feto-placental development, placental histomorphometry, and expression levels of growth factors (VEGF, PLGF, IGF1, IGF2, and GLUT1), hormonal (Dio2) and inflammatory mediators (TNFα, IL10, and IL6), markers of hypoxia (HIF1α) and oxidative damage (8-OHdG), antioxidant enzymes (SOD1, Cat, and GPx1), and endoplasmic reticulum stress mediators (ATF4, GRP78, and CHOP) were evaluated on day 18 of gestation. Daily treatment with Kp-10 increased free T3 and T4 levels and improved fetal weight. Both treatments reestablished the glycogen cell population in the junctional zone. Daily treatment with Kp-10 increased the gene expression levels of Plgf, Igf1, and Glut1 in the placenta of hypothyroid animals, in addition to blocking the increase in 8-OHdG and increasing protein and/or mRNA expression levels of SOD1, Cat, and GPx1. Daily treatment with Kp-10 did not alter the higher protein expression levels of VEGF, HIF1α, IL10, GRP78, and CHOP caused by hypothyroidism in the junctional zone compared to control, nor the lower expression of Dio2 caused by hypothyroidism. However, in the labyrinth zone, this treatment restored the expression of VEGF and IL10 and reduced the GRP78 and CHOP immunostaining. These findings demonstrate that daily treatment with Kp-10 improves fetal development and placental morphology in hypothyroid rats, blocks placental oxidative damage, and increases the expression of growth factors and antioxidant enzymes in the placenta.
Assuntos
Hipotireoidismo , Placentação , Animais , Antioxidantes/metabolismo , Feminino , Desenvolvimento Fetal , Transportador de Glucose Tipo 1/metabolismo , Hipotireoidismo/tratamento farmacológico , Interleucina-10/metabolismo , Kisspeptinas/metabolismo , Estresse Oxidativo , Placenta/metabolismo , Gravidez , Ratos , Ratos Wistar , Superóxido Dismutase-1/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Background: Hypothyroidism causes ovarian dysfunction and infertility in women, in addition to being associated with hyperprolactinemia and reduced hypothalamic expression of kisspeptin (Kp). However, it remains unknown whether and how Kp is able to reverse the ovarian dysfunction caused by hypothyroidism. Methods: Hypothyroidism was induced in adult female Wistar rats using 6-propyl-2-thiouracil for 3 months. In the last month, half of the animals received Kp10. Blood samples were collected for dosage of free thyroxine, thyrotropin (TSH), luteinizing hormone (LH), prolactin (PRL), progesterone (P4), and estradiol (E2), and uteruses and ovaries were collected for histomorphometry. Body and ovarian weight and the number of corpora lutea were also evaluated. Half of the brains were evaluated by immunohistochemistry to Kp, and the other half had the arcuate nucleus of hypothalamus (ARC) and preoptic area microdissected for gene evaluation of Kiss1, Nkb, Pdyn, and Gnrh1. The pituitary gland and corpora lutea were also dissected for gene evaluation. Results: Hypothyroidism kept the animals predominantly acyclic and promoted a reduction in ovarian weight, number of corpora lutea, endometrial thickness, number of endometrial glands, and plasma LH, in addition to increasing the luteal messenger RNA (mRNA) expression of Star and Cyp11a1 and reducing 20αHsd. An increase in plasma PRL and P4 levels was also caused by hypothyroidism. Kp immunoreactivity and Kiss1 and Nkb mRNA levels in the ARC and Kiss1 in the anteroventral periventricular nucleus of hypothalamus were reduced in hypothyroid rats. Hypothyroid animals had lower pituitary gene expression of Gnrhr, Lhb, Prl, and Drd2, and an increase in Tshb. The treatment with Kp10 restored estrous cyclicality, plasma LH, ovarian and uterine morphology, and Cyp11a1, 3ßHsd, and 20αHsd mRNA levels in the corpora lutea. Kp10 treatment did not alter gene expression for Kiss1 or Nkb in the ARC of hypothyroid rats. Nevertheless, Kp10 increased Lhb mRNA levels and reduced Tshb in the pituitary compared with the hypothyroid group. Conclusions: The present findings characterize the inhibitory effects of hypothyroidism on the hypothalamic-pituitary-gonadal axis in female rats and demonstrate that Kp10 is able to reverse the ovarian dysfunction caused by hypothyroidism, regardless of hyperprolactinemia.
Assuntos
Hiperprolactinemia , Hipotireoidismo , Feminino , Animais , Ratos , Kisspeptinas/genética , Kisspeptinas/metabolismo , Kisspeptinas/farmacologia , Hiperprolactinemia/metabolismo , Enzima de Clivagem da Cadeia Lateral do Colesterol/metabolismo , Ratos Wistar , Hormônio Luteinizante , Núcleo Arqueado do Hipotálamo/metabolismo , Prolactina/metabolismo , Prolactina/farmacologia , RNA Mensageiro/metabolismoRESUMO
GATA-1 is a transcription factor from the GATA family, which features zinc fingers for DNA binding. This protein was initially identified as a crucial regulator of blood cell differentiation, but it is currently known that the Gata-1 gene expression is not limited to this system. Although the testis is also a site of significant GATA-1 expression, its role in testicular cells remains considerably unexplored. In the present study, we evaluated the testicular morphophysiology of adult ΔdblGATA mice with a mutation in the GATA-1 protein. Regarding testicular histology, GATA-1 mutant mice exhibited few changes in the seminiferous tubules, particularly in germ cells. A high proportion of differentiated spermatogonia, an increased number of apoptotic pre-leptotene spermatocytes (Caspase-3-positive), and a high frequency of sperm head defects were observed in ΔdblGATA mice. The main differences were observed in the intertubular compartment, as ΔdblGATA mice showed several morphofunctional changes in Leydig cells. Reduced volume, increased number and down-regulation of steroidogenic enzymes were observed in ΔdblGATA Leydig cells. Moreover, the mutant animal showed lower serum testosterone concentration and high LH levels. These results are consistent with the phenotypic and biometric data of mutant mice, i.e., shorter anogenital index and reduced accessory sexual gland weight. In conclusion, our findings suggest that GATA-1 protein is an important factor for germ cell differentiation as well as for the steroidogenic activity in the testis.
Assuntos
Espermatogônias , Testículo , Animais , Células Intersticiais do Testículo/metabolismo , Masculino , Camundongos , Mutação/genética , Túbulos Seminíferos , Espermatogônias/metabolismo , Testículo/metabolismo , Testosterona/metabolismoRESUMO
This study compared the effects of aerobic physical training and estradiol (E2) replacement on central pathways involved with thermoregulation in ovariectomized rats. Rats were assigned to untrained ovariectomized treated with placebo (UN-OVX), untrained ovariectomized treated with E2 (E2-OVX), and trained ovariectomized (TR-OVX) groups. Tail skin temperature (TST), internal temperature (Tint), and basal oxygen consumption (VO2) were recorded. Neuronal activity, brain expression of Kiss1, NKB and Prodyn, and central norepinephrine (NE) levels were measured. UN-OVX had the highest TST. Compared to UN-OVX rats, TR-OVX and E2-OVX had lower Fos expression in the paraventricular and arcuate (ARC) nuclei, and lower double labeling for Tyrosine Hydroxylase and Fos in the brainstem. Compared to UN-OVX, only TR-OVX group exhibited lower kisspeptin (Kiss1), neurokinin B (NKB), and prodynorphin expression in the ARC and higher central NE levels. Aerobic physical training before menopause may prevent the heat dissipation imbalance induced by reduction of E2, through central NE release, modulation of Kiss1, NKB and prodynorphin expression in neurons from ARC nucleus.
Assuntos
Kisspeptinas , Neurocinina B , Feminino , Humanos , Ratos , Animais , Kisspeptinas/metabolismo , Neurocinina B/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo , Ovariectomia , Estradiol/farmacologia , Norepinefrina/metabolismo , Regulação da Temperatura CorporalRESUMO
Previous studies have highlighted the positive effects of Estradiol (E2) replacement therapy and physical exercise on skeletal muscle during menopause. However, the comparison effects of exercise training (ET) and estradiol replacement therapy during menopause on skeletal muscle have not been investigated to date. This study aimed to compare the effects of endurance exercise training versus E2 replacement therapy on mitochondrial density, redox status, and inflammatory biomarkers in the skeletal muscle of ovariectomized rats. Thirty female Wistar rats (12-week-old) were randomly assigned into three groups: Untrained ovariectomized rats (UN-OVX, n = 10); untrained ovariectomized rats treated with estradiol replacement therapy (E2-OVX); and, trained ovariectomized rats (TR-OVX). After ovariectomy, the E2-OVX rats were treated subcutaneously with E2 (implanted Silastic® capsule containing 360 µg of 17ß-estradiol/mL) while the TR-OVX group performed an exercise training protocol (50-70% of maximal running speed on a treadmill, 60 min/day, 5 days/week for 8 weeks). After euthanasia, the soleus muscle was processed for histological and biochemical evaluations. Only exercise prevented the reduction of maximal oxygen consumption and increased mechanical efficiency (ME). While mitochondrial muscle density, total antioxidant capacity (FRAP), catalase (CAT) activity, and interleukin 10 levels were higher in TR-OVX, only OVX-E2 presented higher CAT activity and lower interleukin 6 levels. Endurance exercise training compared with E2 replacement therapy maintains the aerobic capacity improving the ME of OVX rats. In addition, only endurance exercise training raises the skeletal muscle mitochondrial content and tends to balance the redox and inflammatory status in the skeletal muscle of OVX rats.
Assuntos
Condicionamento Físico Animal , Animais , Estradiol/farmacologia , Feminino , Terapia de Reposição Hormonal , Humanos , Músculo Esquelético , Ovariectomia , Condicionamento Físico Animal/fisiologia , Ratos , Ratos WistarRESUMO
Parkinson's disease results from a degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNpc) and it is more prevalent in men than in women. Estrogen has neuroprotective action of the nigrostriatal dopaminergic (NSDA) neurons. It was investigated whether differences in plasma 17ß-estradiol (E2) levels alter the degree of neuroprotection in NSDA neurons. Ovariectomized rats, implanted with subcutaneous capsules containing 400, 800 or 1,600 µg of E2 or corn oil, were injected with 1 µg of 6-OHDA in the SNpc or the medial forebrain bundle (MFB). Striatal dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and plasma E2 levels were measured. Only at 400 µg, E2 protected striatal DA against lesion of the MFB. In the SNpc, E2 failed to prevent DA depletion, but increased DOPAC/DA ratio in the striatum. In an NSDA moderate lesion, E2 has a neuroprotective action. In a severe lesion, E2 could stimulate DA activity in remaining neurons.
Assuntos
Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Estrogênios/farmacologia , Oxidopamina/farmacologia , Doença de Parkinson/metabolismo , Substância Negra/efeitos dos fármacos , Animais , Corpo Estriado/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Estrogênios/administração & dosagem , Feminino , Ovariectomia , Ratos , Ratos Wistar , Substância Negra/metabolismoRESUMO
Light is the most powerful temporal cue that entrains physiology and behavior through modulation of the suprachiasmatic nucleus (SCN) of the hypothalamus. However, on a daily basis, individuals face a combination of light and several non-photic cues, such as social interaction. In order to investigate whether SCN activity and SCN-driven rhythms are altered by social interaction, adult male C57BLJ/6 mice were maintained in groups of 3-4 animals per cage or 1 animal per cage (socially isolated) under 12:12 h / light:dark (LD) cycles or constant darkness (DD). Analysis of the two anatomical subdivisions (ventral, v and dorsal, d) of the medial SCN revealed an effect of housing conditions on the d-SCN but not on the v-SCN on the number of c-Fos immunoreactive (ir) neurons. As such, 2 h after the light-phase onset d-SCN c-Fos-ir number was lower in single-housed mice under LD. Importantly, under DD there were no effect of housing conditions in the number of c-Fos-ir SCN neurons. Social isolation increased the amplitude and strength of SCN-driven rhythm of body temperature (Tc) entrained to LD and it advanced its onset, uncoupling with spontaneous locomotor activity (SLA) rhythm, without altering endogenous Tc and SLA rhythms expressed under DD. Associated with reduced Tc in the light phase, single-housed mice showed reduced body weight. However, these phenotypes were not accompanied by changes in the number of c-Fos-ir neurons in the preoptic area (POA), which are known to regulate energy metabolism and Tc. Altogether, these results imply that the social interaction masking effect on the d-SCN is added to that of light stimulus, in order to achieve full c-Fos expression in the SCN, which, in turn seems to be required to maintain daily-phase coherence between the photo-entrained rhythms of Tc and SLA. There might be an inter-relationship between masking (social interaction) and entrainment stimulus (light) that impacts the circadian parameters of the photo-entrained Tc rhythm. As such, in the absence of social interactions a more robust Tc rhythm is shown. This inter-relationship seems to occur in the dorsal subdivision of the SCN but not in the POA.
Assuntos
Ritmo Circadiano , Interação Social , Animais , Escuridão , Masculino , Camundongos , Proteínas Proto-Oncogênicas c-fos/metabolismo , Núcleo SupraquiasmáticoRESUMO
Early-life environmental events that disrupt the mother-pup relationship may induce profound long-lasting changes on several behavioral and neuroendocrine systems. The neonatal handling procedure, which involves repeated brief maternal separations followed by experimental manipulations, reduces sexual behavior and induces anovulatory estrous cycles in female rats. On the afternoon of proestrus, neonatally handled females show a reduced surge of luteinizing hormone (LH) and an increased content of gonadotropin-releasing hormone in the medial preoptic area (MPOA). In order to detect the possible causes for the reduced ovulation and sexual behavior, the present study aimed to analyze the effects of neonatal handling on noradrenaline (NA) and nitric oxide (NO) levels in the MPOA on the afternoon of proestrus. Neonatal handling reduced MHPG (NA metabolite) levels and MHPG/NA ratio in the MPOA, indicating decreased NAergic activity. Additionally, neonatal handling decreased NO levels, as measured by the metabolites (NO(x)), nitrite and nitrate in the same period. We may conclude that the neonatal handling procedure decreased activity of the NAergic and NOergic systems in the MPOA during proestrus, which is involved in the control of LH and FSH secretion, and this may possibly explain the anovulatory estrous cycles and reduced sexual behavior of the neonatally handled female rats.
Assuntos
Manobra Psicológica , Óxido Nítrico/metabolismo , Norepinefrina/metabolismo , Área Pré-Óptica/metabolismo , Reprodução/fisiologia , Animais , Animais Recém-Nascidos , Feminino , Masculino , Gravidez , Ratos , Ratos Wistar , Comportamento Sexual Animal/fisiologiaRESUMO
The neurons that produce gonadotrophin-releasing hormone (GnRH) are mainly found in the medial preoptic area (MPOA) and constitute a common final pathway to the control of luteinizing hormone (LH) surge on proestrus. The control of GnRH secretion depends on several neurotransmitters, such as serotonin (5-HT), noradrenaline (NA), dopamine (DA) and nitric oxide (NO). The aim of this work was to study the profile of 5-HT, catecholamines and their main metabolites in the MPOA throughout the estrous cycle and their interactions with NO system in this area to control LH surge. For this purpose, the following were evaluated: (I) the effect of pargyline (a monoamine oxidase inhibitor) acute treatment on plasma LH secretion throughout the estrous cycle, correlated with changes of 5-HT, DA and NA content as well as activity and expression of neuronal NO synthase (nNOS) within MPOA; (II) the effect of 5,7-dihydroxitriptamine (a drug that depletes 5-HT) microinjection into MPOA on plasma LH in ovariectomized rats treated with oil, estradiol (E(2)) or E(2) plus progesterone (P(4)). Pargyline prevented LH surge on proestrus without altering its basal secretion. Throughout the estrous cycle, pargyline augmented both 5-HT and DA contents in approximately 300% and NA content in 50% in the MPOA. During proestrus, pargyline stimulated nNOS activity at 9 h and inhibited it at 11 h. nNOS expression was inhibited by pargyline at 15 h. Depletion of 5-HT content in the MPOA increased LH secretion in ovariectomized rats treated with E(2) plus P(4), but it did not modify in rats treated with either oil or E(2). Therefore, the present data show that pargyline treatment can inhibit proestrus LH surge through a mechanism that may involve 5-HT and NO systems in the MPOA. Moreover, the effect of 5-HT in the MPOA for limiting LH surge seems to depend on plasma levels of E(2) and P(4).
Assuntos
Monoaminas Biogênicas/metabolismo , Ciclo Estral/efeitos dos fármacos , Hormônio Luteinizante/metabolismo , Inibidores da Monoaminoxidase/farmacologia , Óxido Nítrico/metabolismo , Pargilina/farmacologia , Área Pré-Óptica/efeitos dos fármacos , 5,7-Di-Hidroxitriptamina/farmacologia , Análise de Variância , Animais , Feminino , Ovariectomia/métodos , Radioimunoensaio/métodos , Ratos , Ratos Wistar , Serotoninérgicos/farmacologiaRESUMO
The prefrontal cortex (PFC), amygdala and hippocampus display a coordinated activity during acquisition of associative fear memories. Evidence indicates that PFC engagement in aversive memory formation does not progress linearly as previously thought. Instead, it seems to be recruited at specific time windows after memory acquisition, which has implications for the treatment of post-traumatic stress disorders. Cannabidiol (CBD), the major non-psychotomimetic phytocannabinoid of the Cannabis sativa plant, is known to modulate contextual fear memory acquisition in rodents. However, it is still not clear how CBD interferes with PFC-dependent processes during post-training memory consolidation. Here, we tested whether intra-PFC infusions of CBD immediately after or 5h following contextual fear conditioning was able to interfere with memory consolidation. Neurochemical and cellular correlates of the CBD treatment were evaluated by the quantification of extracellular levels of dopamine (DA), serotonin, and their metabolites in the PFC and by measuring the cellular expression of activity-dependent transcription factors in cortical and limbic regions. Our results indicate that bilateral intra-PFC CBD infusion impaired contextual fear memory consolidation when applied 5h after conditioning, but had no effect when applied immediately after it. This effect was associated with a reduction in DA turnover in the PFC following retrieval 5days after training. We also observed that post-conditioning infusion of CBD reduced c-fos and zif-268 protein expression in the hippocampus, PFC, and thalamus. Our findings support that CBD interferes with contextual fear memory consolidation by reducing PFC influence on cortico-limbic circuits.
Assuntos
Canabidiol/farmacologia , Expressão Gênica/efeitos dos fármacos , Consolidação da Memória/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Animais , Condicionamento Psicológico/efeitos dos fármacos , Medo/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Neurônios/metabolismo , Córtex Pré-Frontal/metabolismo , Ratos Wistar , Transtornos de Estresse Pós-Traumáticos/metabolismo , Fatores de TempoRESUMO
Since locus coeruleus (LC) lesion blocks preovulatory prolactin surge, the aim of this study was to determine if this lesion would also block prolactin surges induced by steroids in ovariectomized rats and would modify basal prolactin secretion. To determine the time of the steroid-induced prolactin surges, ovariectomized rats treated with estradiol (OVE) or estradiol and progesterone (OVEP) were cannulated at 08:00 h and blood samples were collected hourly between 14:00 and 18:00 h. Ovariectomized rats treated with oil (OV-Oil) were used as control. Prolactin peaked at 16:00 h in OVE rats and at 15:00 h in OVEP. In a second experiment, male rats, cycling rats, OVE, OVEP, and OV-Oil groups were cannulated at 08:00 h, followed by LC lesion or sham-surgery. Blood samples were withdrawn at times of basal and peak prolactin levels. LC lesion blocked afternoon prolactin surges of OVE, OVEP and proestrus rats. However, the low levels observed at 16:00 h in OV-Oil, diestrus and male rats as well as at 11:00 h in OVE, OVEP, estrus, and proestrus rats were not modified by LC lesion. The high prolactin levels observed on estrus afternoon were dramatically reduced by LC lesion. Data suggest that LC neurons are important for steroid-induced prolactin surge genesis, but not for prolactin basal secretion.
Assuntos
Ciclo Estral/fisiologia , Locus Cerúleo/metabolismo , Neurônios/metabolismo , Prolactina/metabolismo , Animais , Feminino , Locus Cerúleo/lesões , Masculino , Ovariectomia , Prolactina/sangue , Ratos , Ratos WistarRESUMO
The aim of this study was to describe and validate a method to evaluate the preovulatory surges of gonadotropins in rats submitted to anesthesia and implantation of a jugular vein cannula in the morning of proestrus and to withdrawal of serial blood samples in the afternoon of the same day. In experiment I, to choose an adequate anesthetic, cycling female rats were anesthetized in the morning of proestrus (10:00-11:00 h) with tribromoethanol, ketamine/xylazine or tiletamine/zolazepam and a Silastic cannula was implanted into the jugular vein. Blood samples (0.6 ml) were withdrawn hourly between 12:00 and 18:00 h of the same day and, on estrus morning, the rats were decapitated and the number of ova was counted. The preovulatory gonadotropin surges as well as ovulation occurred in rats anesthetized with tribromoethanol, while they were prevented by ketamine/xylazine or tiletamine/zolazepam. To investigate if the jugular cannulation under tribromoethanol anesthesia and serial blood sampling performed in experiment I altered the magnitude of the gonadotropin surges and the number of ova, intact rats (control) or rats anesthetized with tribromoethanol followed or not by jugular vein cannulation were decapitated at 16:00 h of proestrus and in the morning of estrus. The magnitude of preovulatory gonadotropin surges and the number of ova were not different among groups. Thus, since neither tribromoethanol nor surgical procedures or serial blood sampling altered the preovulatory gonadotropin surges or the ovulation process, this method seems to be suitable for this sort of study in rats.